Cooling Fan Circuit Diagnosis 1.6L
Circuit Description
The engine cooling fan circuit operates the main cooling fan and the auxiliary cooling fan. The cooling fans are controlled by the engine control module (ECM) based on inputs from the engine coolant temperature (ECT) sensor and the air conditioning pressure (ACP) sensor. The ECM controls the low speed cooling fan operation by internally grounding the ECM connector terminal 10. This energizes the low speed cooling fan relay and operates the main cooling fan and the auxiliary cooling fan at low speed as the cooling fans are connected in a series circuit. The ECM controls the high speed cooling fan operation by internally grounding the ECM connector terminal 10 and the ECM connector terminal 9 at the same time. This energizes the low speed cooling fan relay, the high speed cooling fan relay, and the series/parallel cooling fan relay resulting in high speed fan operation as the cooling fans are now connected in a parallel circuit.
Diagnostic Aids
| • | If the owner complained of an overheating condition, it must be determined if the complaint was due to an actual boil over or the engine coolant temperature gage indicated overheating. If the engine is overheating and the cooling fans are ON, the cooling system should be inspected. |
| • | If the engine fuse block fuses Ef6 become open immediately after installation, inspect for a short to ground in the wiring of the appropriate circuit. If the fuses become open when the cooling fans are to be turned ON by the ECM, suspect a faulty cooling fan motor. |
| • | The ECM will turn the cooling fans ON at low speed when the coolant temperature is 97°C (207°F). The ECM will turn the cooling fans OFF when the coolant temperature is 94°C (201°F). |
| • | The ECM will turn the cooling fans ON at high speed when the coolant temperature is 101°C (214°F). The ECM will change the cooling fans from high speed to low speed when the coolant temperature is 98°C (208°F). |
| • | The ECM will turn the cooling fans ON at low speed when the A/C system is ON. The ECM will change the cooling fans from low speed to high speed when the high side A/C pressure is 1 882 kPa (273 psi) then return to low speed when the high side A/C pressure is 1 448 kPa (210 psi). When the A/C system is ON, the ECM will change the cooling fans from low to high speed when the coolant temperature reaches 117°C (244°F) then return to low speed when the coolant temperature reaches 114°C (237°F). |
| • | The cooling fan circuit can be inspected quickly by disconnecting the ECM connector 2 and grounding the connector terminal 10. This should create low speed cooling fan operation with the ignition ON. By grounding the ECM connector terminals 10 and 9 and turning the ignition ON, high speed cooling fan operation should be achieved. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step, along with step 5, inspects the ability of the ECM to operate the cooling fans.
-
This step, along with step 9, inspects the ability of the ECM to operate the cooling fans in response to A/C pressure readings.
-
After confirming battery voltage and the ECM supplying a ground to the coil side of the cooling fan relay low, by jumpering connector terminals 30 and 87 it will be determined if the relay is at fault or a wiring condition is present.
-
This step inspects for the presence of battery voltage to the main cooling fan when the A/C is ON. If battery voltage is present and the cooling fans are not operating, the condition is in the ground side of the cooling fan circuit.
-
By directly grounding the ECM connector terminals 10 and 9, the main and auxiliary cooling fans should run at high speed.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 1.6L |
2 |
Is the fuse OK? | Go to Step 3 | Go to Diagnostic Aids |
3 |
Is the fuse OK? | Go to Step 4 | Go to Diagnostic Aids |
Do the cooling fans run at low speed? | Go to Step 5 | Go to Step 10 | |
5 |
Do the cooling fans run at high speed? | Go to Step 6 | Go to Step 33 |
6 |
Does the A/C compressor clutch engage? | Go to Step 8 | Go to Step 7 |
7 |
Does the A/C compressor clutch engage? | Go to Step 8 | -- |
Do the cooling fans run at low speed? | Go to Step 9 | Go to Step 31 | |
9 |
Do the cooling fans run at high speed? | Go to Step 10 | -- |
10 |
Is the test light ON? | Go to Step 11 | Go to Step 12 |
11 |
Is the test light ON? | Go to Step 28 | Go to Step 17 |
12 |
Is the test light ON? | Go to Step 13 | Go to Step 24 |
13 |
Do the cooling fans run at low speed? | Go to Step 30 | Go to Step 14 |
14 | Inspect for an open wire between the low speed cooling fan relay connector terminal 86 and the ECM connector terminal 10. Is the condition found? | Go to Step 25 | Go to Step 15 |
15 |
Is the test light ON? | Go to Step 16 | Go to Step 23 |
Connect a fused jumper between the cooling fan relay low connector terminals 30 and 87. Do the cooling fans run at low speed? | Go to Step 26 | Go to Step 17 | |
17 |
Do the cooling fans run at low speed? | Go to Step 27 | Go to Step 18 |
18 | Inspect the wire between the cooling fan relay low connector terminal 87 to the main cooling fan connector terminal 2 for an open. Is the condition found? | Go to Step 22 | Go to Step 19 |
19 | Inspect the wire between the main cooling fan connector terminal 1 and the cooling fan control relay connector terminal 30 for an open. Is the condition found? | Go to Step 22 | Go to Step 20 |
20 | Inspect the wire between the cooling fan control relay connector terminal 87A and the auxiliary cooling fan connector terminal 2 for an open. Is the condition found? | Go to Step 22 | Go to Step 21 |
21 | Inspect for an open wire between the auxiliary cooling fan connector terminal 1 and ground. Is the condition found? | Go to Step 22 | Go to Step 29 |
22 | Repair the open wire as needed. Is the repair complete? | System OK | -- |
23 | Repair the open between the cooling fan relay low connector terminal 30 and the fuse Ef6. Is the repair complete? | System OK | -- |
24 | Repair the open between the cooling fan relay low connector terminal 86 and the ignition switch. Is the repair complete? | System OK | -- |
25 | Repair the open wire between the cooling fan relay low connector terminal 85 and the ECM connector terminal 10. Is the repair complete? | System OK | -- |
26 | Replace the cooling fan relay low. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
27 | Replace the cooling fan control relay. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
28 | Replace the main cooling fan. Refer to Engine Cooling Fan Replacement . Is the replacement complete? | System OK | -- |
29 | Replace the auxiliary cooling fan. Refer to Engine Cooling Fan Replacement . Is the replacement complete? | System OK | -- |
30 | Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls - 1.6L. Is the replacement complete? | System OK | -- |
31 |
Is the test light ON? | Go to Step 32 | Go to Step 12 |
32 |
Is the test light ON? | Go to Step 28 | Go to Step 17 |
33 |
Is the test light ON? | Go to Step 34 | Go to Step 44 |
34 |
Is the test light ON? | Go to Step 35 | Go to Step 45 |
35 |
Is the test light ON? | Go to Step 36 | Go to Step 46 |
36 |
Is the test light ON? | Go to Step 37 | Go to Step 47 |
Do the cooling fans run at high speed? | Go to Step 30 | Go to Step 38 | |
38 |
Is the condition found? | Go to Step 22 | Go to Step 39 |
39 |
Is the test light ON? | Go to Step 40 | Go to Step 48 |
40 |
Is the test light ON? | Go to Step 41 | Go to Step 49 |
41 |
Do the cooling fans run at high speed? | Go to Step 43 | Go to Step 42 |
42 |
Do the cooling fans run at high speed? | Go to Step 27 | -- |
43 | Replace the cooling fan relay high. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
44 | Repair the open wire between the cooling fan relay high connector terminal 86 and the ignition switch. Is the repair complete? | System OK | -- |
45 | Repair the open wire between the cooling fan relay high connector terminal 30 and the battery. Is the repair complete? | System OK | -- |
46 | Repair the open wire between the cooling fan control relay connector terminal 85 and the ignition switch. Is the repair complete? | System OK | -- |
47 | Repair the open wire between the cooling fan control relay connector terminal 87 and ground. Is the repair complete? | System OK | -- |
48 | Repair the open wire between the cooling fan relay high connector terminal 87 and the auxiliary cooling fan connector terminal 2. Is the repair complete? | System OK | -- |
49 | Repair the open wire between the cooling fan control relay connector terminal 85 and the ECM connector terminal 9. Is the repair complete? | System OK | -- |
Cooling Fan Circuit Diagnosis 1.8L European and N.A. Emissions
Circuit Description
The engine cooling fan circuit operates the main cooling fan and the auxiliary cooling fan. The cooling fans are controlled by the engine control module (ECM) based on inputs from the engine coolant temperature (ECT) sensor and the air conditioning pressure (ACP) sensor. The ECM controls the low speed cooling fan operation by internally grounding the ECM connector terminal K28. This energizes the low speed cooling fan relay and operates the main cooling fan and the auxiliary cooling fan at low speed as the cooling fans are connected in a series circuit. The ECM controls the high speed cooling fan operation by internally grounding the ECM connector terminal K28 and the ECM connector terminal K12 at the same time. This energizes the low speed cooling fan relay, the high speed cooling fan relay, and the series/parallel cooling fan relay resulting in high speed fan operation as the cooling fans are now connected in a parallel circuit.
Diagnostic Aids
| • | If the owner complained of an overheating condition, it must be determined if the complaint was due to an actual boil over, or the engine coolant temperature gage indicated overheating. If the engine is overheating and the cooling fans are ON, the cooling system should be inspected. |
| • | If the engine fuse block fuses Ef21, Ef6, or Ef8 become open immediately after installation, inspect for a short to ground in the wiring of the appropriate circuit. If the fuses become open when the cooling fans are to be turned ON by the ECM, suspect a faulty cooling fan motor. |
| • | The ECM will turn the cooling fans ON at low speed when the coolant temperature is 97°C (207°F). The ECM will turn the cooling fans OFF when the coolant temperature is 94°C (201°F). |
| • | The ECM will turn the cooling fans ON at high speed when the coolant temperature is 101°C (214°F). The ECM will change the cooling fans from high speed to low speed when the coolant temperature is 98°C (208°F). |
| • | The ECM will turn the cooling fans ON at low speed when the A/C system is ON. The ECM will change the cooling fans from low speed to high speed when the high side A/C pressure is 1 882 kPa (273 psi) then return to low speed when the high side A/C pressure is 1 448 kPa (210 psi). When the A/C system is ON, the ECM will change the cooling fans from low to high speed when the coolant temperature reaches 117°C (244°F) then return to low speed when the coolant temperature reaches 114°C (237°F). |
| • | The cooling fan circuit can be inspected quickly by disconnecting the ECM connector 2 and grounding the connector terminal K28. This should create low speed cooling fan operation with the ignition ON. By grounding the ECM connector terminals K28 and K12 and turning the ignition ON, high speed cooling fan operation should be achieved. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step, along with step 5, inspects the ability of the ECM to operate the cooling fans.
-
This step, along with step 9, inspects the ability of the ECM to operate the cooling fans in response to A/C pressure readings.
-
After confirming battery voltage and the ECM supplying a ground to the coil side of the cooling fan relay A, by jumpering connector terminals 30 and 87 it will be determined if the relay is at fault or a wiring condition is present.
-
This step inspects for the presence of battery voltage to the main cooling fan when the A/C is ON. If battery voltage is present and the cooling fans are not operating, the condition is in the ground side of the cooling fan circuit.
-
By directly grounding the ECM connector terminals K28 and K12, the main and auxiliary cooling fans should run at high speed.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 1.8L |
2 |
Is the fuse OK? | Go to Step 3 | Go to Diagnostic Aids |
3 |
Is the fuse OK? | Go to Step 4 | Go to Diagnostic Aids |
Do the cooling fans run at low speed? | Go to Step 5 | Go to Step 10 | |
5 |
Do the cooling fans run at high speed? | Go to Step 6 | Go to Step 33 |
6 |
Does the A/C compressor clutch engage? | Go to Step 8 | Go to Step 7 |
7 |
Does the A/C compressor clutch engage? | Go to Step 8 | -- |
Do the cooling fans run at low speed? | Go to Step 9 | Go to Step 31 | |
9 |
Do the cooling fans run at high speed? | Go to Step 10 | -- |
10 |
Is the test light ON? | Go to Step 11 | Go to Step 12 |
11 |
Is the test light ON? | Go to Step 28 | Go to Step 17 |
12 |
Is the test light ON? | Go to Step 13 | Go to Step 24 |
13 |
Do the cooling fans run at low speed? | Go to Step 30 | Go to Step 14 |
14 | Inspect for an open wire between the low speed cooling fan relay connector terminal 85 and the ECM connector terminal K28. Is the condition found? | Go to Step 25 | Go to Step 15 |
15 |
Is the test light ON? | Go to Step 16 | Go to Step 23 |
Connect a fused jumper between the cooling fan relay low connector terminals 30 and 87. Do the cooling fans run at low speed? | Go to Step 26 | Go to Step 17 | |
17 |
Do the cooling fans run at low speed? | Go to Step 27 | Go to Step 18 |
18 | Inspect the wire between the cooling fan relay low connector terminal 87 to the main cooling fan connector terminal 2 for an open. Is the condition found? | Go to Step 22 | Go to Step 19 |
19 | Inspect the wire between the main cooling fan connector terminal 1 and the cooling fan control relay connector terminal 30 for an open. Is the condition found? | Go to Step 22 | Go to Step 20 |
20 | Inspect the wire between the cooling fan control relay connector terminal 87A and the auxiliary cooling fan connector terminal 2 for an open. Is the condition found? | Go to Step 22 | Go to Step 21 |
21 | Inspect for an open wire between the auxiliary cooling fan connector terminal 1 and ground. Is the condition found? | Go to Step 22 | Go to Step 29 |
22 | Repair the open wire as needed. Is the repair complete? | System OK | -- |
23 | Repair the open between the cooling fan relay low connector terminal 30 and the fuse Ef21. Is the repair complete? | System OK | -- |
24 | Repair the open between the cooling fan relay low connector terminal 86 and the ignition switch. Is the repair complete? | System OK | -- |
25 | Repair the open wire between the cooling fan relay low connector terminal 85 and the ECM connector terminal K28. Is the repair complete? | System OK | -- |
26 | Replace the cooling fan relay low. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
27 | Replace the cooling fan control relay. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
28 | Replace the main cooling fan. Refer to Engine Cooling Fan Replacement . Is the replacement complete? | System OK | -- |
29 | Replace the auxiliary cooling fan. Refer to Engine Cooling Fan Replacement . Is the replacement complete? | System OK | -- |
30 | Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls - 1.8L. Is the replacement complete? | System OK | -- |
Is the test light ON? | Go to Step 32 | Go to Step 12 | |
32 |
Is the test light ON? | Go to Step 28 | Go to Step 17 |
33 |
Is the test light ON? | Go to Step 34 | Go to Step 44 |
34 |
Is the test light ON? | Go to Step 35 | Go to Step 45 |
35 |
Is the test light ON? | Go to Step 36 | Go to Step 46 |
36 |
Is the test light ON? | Go to Step 37 | Go to Step 47 |
Do the cooling fans run at high speed? | Go to Step 30 | Go to Step 38 | |
38 |
Is the condition found? | Go to Step 22 | Go to Step 39 |
39 |
Is the test light ON? | Go to Step 40 | Go to Step 48 |
40 |
Is the test light ON? | Go to Step 41 | Go to Step 49 |
41 |
Do the cooling fans run at high speed? | Go to Step 43 | Go to Step 42 |
42 |
Do the cooling fans run at high speed? | Go to Step 27 | -- |
43 | Replace the cooling fan relay high. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
44 | Repair the open wire between the cooling fan relay high connector terminal 86 and the ignition switch. Is the repair complete? | System OK | -- |
45 | Repair the open wire between the cooling fan relay high connector terminal 30 and the battery. Is the repair complete? | System OK | -- |
46 | Repair the open wire between the cooling fan control relay connector terminal 85 and the ignition switch. Is the repair complete? | System OK | -- |
47 | Repair the open wire between the cooling fan control relay connector terminal 87 and ground. Is the repair complete? | System OK | -- |
48 | Repair the open wire between the cooling fan relay high connector terminal 87 and the auxiliary cooling fan connector terminal 2. Is the repair complete? | System OK | -- |
49 | Repair the open wire between the cooling fan control relay connector terminal 85 and the ECM connector terminal K12. Is the repair complete? | System OK | -- |
Cooling Fan Circuit Diagnosis 1.8L Non European Emissions
Circuit Description
The engine cooling fan circuit operates the main cooling fan and the auxiliary cooling fan. The cooling fans are controlled by the engine control module (ECM) based on inputs from the engine coolant temperature (ECT) sensor and the air conditioning pressure (ACP) sensor. The ECM controls the low speed cooling fan operation by internally grounding the ECM connector terminal B27. This energizes the low speed cooling fan relay and operates the main cooling fan and the auxiliary cooling fan at low speed as the cooling fans are connected in a series circuit. The ECM controls the high speed cooling fan operation by internally grounding the ECM connector terminal B27 and the ECM connector terminal B12 at the same time. This energizes the low speed cooling fan relay, the high speed cooling fan relay, and the series/parallel cooling fan relay resulting in high speed fan operation as the cooling fans are now connected in a parallel circuit.
Diagnostic Aids
| • | If the owner complained of an overheating condition, it must be determined if the complaint was due to an actual boil over or the engine coolant temperature gage indicated overheating. If the engine is overheating and the cooling fans are ON, the cooling system should be inspected. |
| • | If the engine fuse block fuses Ef6 become open immediately after installation, inspect for a short to ground in the wiring of the appropriate circuit. If the fuses become open when the cooling fans are to be turned ON by the ECM, suspect a faulty cooling fan motor. |
| • | The ECM will turn the cooling fans ON at low speed when the coolant temperature is 97°C (207°F). The ECM will turn the cooling fans OFF when the coolant temperature is 94°C (201°F). |
| • | The ECM will turn the cooling fans ON at high speed when the coolant temperature is 101°C (214°F). The ECM will change the cooling fans from high speed to low speed when the coolant temperature is 98°C (208°F). |
| • | The ECM will turn the cooling fans ON at low speed when the A/C system is ON. The ECM will change the cooling fans from low speed to high speed when the high side A/C pressure is 1 882 kPa (273 psi) then return to low speed when the high side A/C pressure is 1 448 kPa (210 psi). When the A/C system is ON, the ECM will change the cooling fans from low to high speed when the coolant temperature reaches 117°C (244°F) then return to low speed when the coolant temperature reaches 114°C (237°F). |
| • | The cooling fan circuit can be inspected quickly by disconnecting the ECM connector 2 and grounding the connector terminal B27. This should create low speed cooling fan operation with the ignition ON. By grounding the ECM connector terminals B27 and B12 and turning the ignition ON, high speed cooling fan operation should be achieved. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step, along with step 5, inspects the ability of the ECM to operate the cooling fans.
-
This step, along with step 9, inspects the ability of the ECM to operate the cooling fans in response to A/C pressure readings.
-
After confirming battery voltage and the ECM supplying a ground to the coil side of the cooling fan relay low, by jumpering connector terminals 30 and 87 it will be determined if the relay is at fault or a wiring condition is present.
-
This step inspects for the presence of battery voltage to the main cooling fan when the A/C is ON. If battery voltage is present and the cooling fans are not operating, the condition is in the ground side of the cooling fan circuit.
-
By directly grounding the ECM connector terminals B27 and B12, the main and auxiliary cooling fans should run at high speed.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 1.8L |
2 |
Is the fuse OK? | Go to Step 3 | Go to Diagnostic Aids |
3 |
Is the fuse OK? | Go to Step 4 | Go to Diagnostic Aids |
Do the cooling fans run at low speed? | Go to Step 5 | Go to Step 10 | |
5 |
Do the cooling fans run at high speed? | Go to Step 6 | Go to Step 33 |
6 |
Does the A/C compressor clutch engage? | Go to Step 8 | Go to Step 7 |
7 |
Does the A/C compressor clutch engage? | Go to Step 8 | -- |
Do the cooling fans run at low speed? | Go to Step 9 | Go to Step 31 | |
9 |
Do the cooling fans run at high speed? | Go to Step 10 | -- |
10 |
Is the test light ON? | Go to Step 11 | Go to Step 12 |
11 |
Is the test light ON? | Go to Step 28 | Go to Step 17 |
12 |
Is the test light ON? | Go to Step 13 | Go to Step 24 |
13 |
Do the cooling fans run at low speed? | Go to Step 30 | Go to Step 14 |
14 | Inspect for an open wire between the low speed cooling fan relay connector terminal 85 and the ECM connector terminal B27. Is the condition found? | Go to Step 25 | Go to Step 15 |
15 |
Is the test light ON? | Go to Step 16 | Go to Step 23 |
Connect a fused jumper between the cooling fan relay low connector terminals 30 and 87. Do the cooling fans run at low speed? | Go to Step 26 | Go to Step 17 | |
17 |
Do the cooling fans run at low speed? | Go to Step 27 | Go to Step 18 |
18 | Inspect the wire between the cooling fan relay low connector terminal 87 to the main cooling fan connector terminal 2 for an open. Is the condition found? | Go to Step 22 | Go to Step 19 |
19 | Inspect the wire between the main cooling fan connector terminal 1 and the cooling fan control relay connector terminal 30 for an open. Is the condition found? | Go to Step 22 | Go to Step 20 |
20 | Inspect the wire between the cooling fan control relay connector terminal 87A and the auxiliary cooling fan connector terminal 2 for an open. Is the condition found? | Go to Step 22 | Go to Step 21 |
21 | Inspect for an open wire between the auxiliary cooling fan connector terminal 1 and ground. Is the condition found? | Go to Step 22 | Go to Step 29 |
22 | Repair the open wire as needed. Is the repair complete? | System OK | -- |
23 | Repair the open between the cooling fan relay low connector terminal 30 and the fuse Ef6. Is the repair complete? | System OK | -- |
24 | Repair the open between the cooling fan relay low connector terminal 86 and the ignition switch. Is the repair complete? | System OK | -- |
25 | Repair the open wire between the cooling fan relay low connector terminal 85 and the ECM connector terminal B27. Is the repair complete? | System OK | -- |
26 | Replace the cooling fan relay low. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
27 | Replace the cooling fan control relay. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
28 | Replace the main cooling fan. Refer to Engine Cooling Fan Replacement . Is the replacement complete? | System OK | -- |
29 | Replace the auxiliary cooling fan. Refer to Engine Cooling Fan Replacement . Is the replacement complete? | System OK | -- |
30 | Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls - 1.8L. Is the replacement complete? | System OK | -- |
Is the test light ON? | Go to Step 32 | Go to Step 12 | |
32 |
Is the test light ON? | Go to Step 28 | Go to Step 17 |
33 |
Is the test light ON? | Go to Step 34 | Go to Step 44 |
34 |
Is the test light ON? | Go to Step 35 | Go to Step 45 |
35 |
Is the test light ON? | Go to Step 36 | Go to Step 46 |
36 |
Is the test light ON? | Go to Step 37 | Go to Step 47 |
Do the cooling fans run at high speed? | Go to Step 30 | Go to Step 38 | |
38 |
Is the condition found? | Go to Step 22 | Go to Step 39 |
39 |
Is the test light ON? | Go to Step 40 | Go to Step 48 |
40 |
Is the test light ON? | Go to Step 41 | Go to Step 49 |
41 |
Do the cooling fans run at high speed? | Go to Step 43 | Go to Step 42 |
42 |
Do the cooling fans run at high speed? | Go to Step 27 | -- |
43 | Replace the cooling fan relay high. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
44 | Repair the open wire between the cooling fan relay high connector terminal 86 and the ignition switch. Is the repair complete? | System OK | -- |
45 | Repair the open wire between the cooling fan relay high connector terminal 30 and the battery. Is the repair complete? | System OK | -- |
46 | Repair the open wire between the cooling fan control relay connector terminal 85 and the ignition switch. Is the repair complete? | System OK | -- |
47 | Repair the open wire between the cooling fan control relay connector terminal 87 and ground. Is the repair complete? | System OK | -- |
48 | Repair the open wire between the cooling fan relay high connector terminal 87 and the auxiliary cooling fan connector terminal 2. Is the repair complete? | System OK | -- |
49 | Repair the open wire between the cooling fan control relay connector terminal 85 and the ECM connector terminal B12. Is the repair complete? | System OK | -- |
Cooling Fan Circuit Diagnosis 2.0L
Circuit Description
The engine cooling fan circuit operates the main cooling fan and the auxiliary cooling fan. The cooling fans are controlled by the engine control module (ECM) based on inputs from the engine coolant temperature (ECT) sensor and the air conditioning pressure (ACP) sensor. The ECM controls the low speed cooling fan operation by internally grounding the ECM connector terminal K28. This energizes the low speed cooling fan relay and operates the main cooling fan and the auxiliary cooling fan at low speed as the cooling fans are connected in a series circuit. The ECM controls the high speed cooling fan operation by internally grounding the ECM connector terminal K28 and the ECM connector terminal K12 at the same time. This energizes the low speed cooling fan relay, the high speed cooling fan relay, and the series/parallel cooling fan relay resulting in high speed fan operation as the cooling fans are now connected in a parallel circuit.
Diagnostic Aids
| • | If the owner complained of an overheating condition, it must be determined if the complaint was due to an actual boil over, or the engine coolant temperature gage indicated overheating. If the engine is overheating and the cooling fans are ON, the cooling system should be inspected. |
| • | If the engine fuse block fuse Ef6 becomes open immediately after installation, inspect for a short to ground in the wiring of the appropriate circuit. If the fuse becomes open when the cooling fans are to be turned ON by the ECM, suspect a faulty cooling fan motor. |
| • | The ECM will turn the cooling fans ON at low speed when the coolant temperature is 97°C (207°F). The ECM will turn the cooling fans OFF when the coolant temperature is 94°C (201°F). |
| • | The ECM will turn the cooling fans ON at high speed when the coolant temperature is 101°C (214°F). The ECM will change the cooling fans from high speed to low speed when the coolant temperature is 98°C (208°F). |
| • | The ECM will turn the cooling fans ON at low speed when the A/C system is ON. The ECM will change the cooling fans from low speed to high speed when the high side A/C pressure is 1 882 kPa (273 psi) then return to low speed when the high side A/C pressure is 1 448 kPa (210 psi). When the A/C system is ON, the ECM will change the cooling fans from low to high speed when the coolant temperature reaches 117°C (244°F) then return to low speed when the coolant temperature reaches 114°C (237°F). |
| • | The cooling fan circuit can be inspected quickly by disconnecting the ECM connector 2 and grounding the connector terminal K28. This should create low speed cooling fan operation with the ignition ON. By grounding the ECM connector terminals K28 and K12 and turning the ignition ON, high speed cooling fan operation should be achieved. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step, along with step 5, inspects the ability of the ECM to operate the cooling fans.
-
This step, along with step 9, inspects the ability of the ECM to operate the cooling fans in response to A/C pressure readings.
-
After confirming battery voltage and the ECM supplying a ground to the coil side of the cooling fan relay A, by jumpering connector terminals 30 and 87 it will be determined if the relay is at fault or a wiring condition is present.
-
This step inspects for the presence of battery voltage to the main cooling fan when the A/C is ON. If battery voltage is present and the cooling fans are not operating, the condition is in the ground side of the cooling fan circuit.
-
By directly grounding the ECM connector terminals K28 and K12, the main and auxiliary cooling fans should run at high speed.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 2.0L |
2 |
Is the fuse OK? | Go to Step 3 | Go to Diagnostic Aids |
3 |
Is the fuse OK? | Go to Step 4 | Go to Diagnostic Aids |
Do the cooling fans run at low speed? | Go to Step 5 | Go to Step 10 | |
5 |
Do the cooling fans run at high speed? | Go to Step 6 | Go to Step 33 |
6 |
Does the A/C compressor clutch engage? | Go to Step 8 | Go to Step 7 |
7 |
Does the A/C compressor clutch engage? | Go to Step 8 | -- |
Do the cooling fans run at low speed? | Go to Step 9 | Go to Step 31 | |
9 |
Do the cooling fans run at high speed? | Go to Step 10 | -- |
10 |
Is the test light ON? | Go to Step 11 | Go to Step 12 |
11 |
Is the test light ON? | Go to Step 28 | Go to Step 17 |
12 |
Is the test light ON? | Go to Step 13 | Go to Step 24 |
13 |
Do the cooling fans run at low speed? | Go to Step 30 | Go to Step 14 |
14 | Inspect for an open wire between the low speed cooling fan relay connector terminal 86 and the ECM connector terminal K28. Is the condition found? | Go to Step 25 | Go to Step 15 |
15 |
Is the test light ON? | Go to Step 16 | Go to Step 23 |
Connect a fused jumper between the cooling fan relay low connector terminals 30 and 87. Do the cooling fans run at low speed? | Go to Step 26 | Go to Step 17 | |
17 |
Do the cooling fans run at low speed? | Go to Step 27 | Go to Step 18 |
18 | Inspect the wire between the cooling fan relay low connector terminal 87 to the main cooling fan connector terminal 2 for an open. Is the condition found? | Go to Step 22 | Go to Step 19 |
19 | Inspect the wire between the main cooling fan connector terminal 1 and the cooling fan control relay connector terminal 30 for an open. Is the condition found? | Go to Step 22 | Go to Step 20 |
20 | Inspect the wire between the cooling fan control relay connector terminal 87A and the auxiliary cooling fan connector terminal 2 for an open. Is the condition found? | Go to Step 22 | Go to Step 21 |
21 | Inspect for an open wire between the auxiliary cooling fan connector terminal 1 and ground. Is the condition found? | Go to Step 22 | Go to Step 29 |
22 | Repair the open wire as needed. Is the repair complete? | System OK | -- |
23 | Repair the open between the cooling fan relay low connector terminal 30 and the fuse Ef6. Is the repair complete? | System OK | -- |
24 | Repair the open between the cooling fan relay low connector terminal 86 and the ignition switch. Is the repair complete? | System OK | -- |
25 | Repair the open wire between the cooling fan relay low connector terminal 85 and the ECM connector terminal K28. Is the repair complete? | System OK | -- |
26 | Replace the cooling fan relay low. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
27 | Replace the cooling fan control relay. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
28 | Replace the main cooling fan. Refer to Engine Cooling Fan Replacement . Is the replacement complete? | System OK | -- |
29 | Replace the auxiliary cooling fan. Refer to Engine Cooling Fan Replacement . Is the replacement complete? | System OK | -- |
30 | Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls - 2.0L. Is the replacement complete? | System OK | -- |
Is the test light ON? | Go to Step 32 | Go to Step 12 | |
32 |
Is the test light ON? | Go to Step 28 | Go to Step 17 |
33 |
Is the test light ON? | Go to Step 34 | Go to Step 44 |
34 |
Is the test light ON? | Go to Step 35 | Go to Step 45 |
35 |
Is the test light ON? | Go to Step 36 | Go to Step 46 |
36 |
Is the test light ON? | Go to Step 37 | Go to Step 47 |
Do the cooling fans run at high speed? | Go to Step 30 | Go to Step 38 | |
38 |
Is the condition found? | Go to Step 22 | Go to Step 39 |
39 |
Is the test light ON? | Go to Step 40 | Go to Step 48 |
40 |
Is the test light ON? | Go to Step 41 | Go to Step 49 |
41 |
Do the cooling fans run at high speed? | Go to Step 43 | Go to Step 42 |
42 |
Do the cooling fans run at high speed? | Go to Step 27 | -- |
43 | Replace the cooling fan relay high. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
44 | Repair the open wire between the cooling fan relay high connector terminal 86 and the ignition switch. Is the repair complete? | System OK | -- |
45 | Repair the open wire between the cooling fan relay high connector terminal 30 and the battery. Is the repair complete? | System OK | -- |
46 | Repair the open wire between the cooling fan control relay connector terminal 85 and the ignition switch. Is the repair complete? | System OK | -- |
47 | Repair the open wire between the cooling fan control relay connector terminal 87 and ground. Is the repair complete? | System OK | -- |
48 | Repair the open wire between the cooling fan relay high connector terminal 87 and the auxiliary cooling fan connector terminal 2. Is the repair complete? | System OK | -- |
49 | Repair the open wire between the cooling fan control relay connector terminal 85 and the ECM connector terminal K12. Is the repair complete? | System OK | -- |
