Engine Cranks But Does Not Run LD9
Circuit Description
This engine is equipped with a distributorless ignition system called the Electronic Ignition (EI) system. The primary circuit of the EI system consists of the following items:
| • | Two separate ignition coils |
| • | Electronic Ignition Control Module (ICM) |
| • | Crankshaft Position (CKP) sensor |
| • | Related connecting wires and the ignition control portion of the PCM |
Each secondary circuit consists of the following items:
| • | Secondary winding of the coil |
| • | Two connecting metal strips that are molded into the coil housing |
| • | Spark plug boot/connector assemblies |
| • | Spark plugs |
Diagnostic Aids
| • | A small amount of resistance in the battery positive voltage circuit to the PCM may cause a no start with a functioning MIL. Check the battery positive voltage circuit for excessive resistance or corrosion. |
| • | Loss of Serial Data from the PCM to the IPC will cause no start condition. |
| • | Check the Throttle Position (TP) sensor for the following conditions: |
| - | Binding |
| - | Sticking |
| - | Intermittently shorted |
| - | Intermittently open |
| • | If the THEFT SYSTEM telltale is flashing on the Instrument Panel Cluster (IPC), the theft deterrent system has been activated, refer to DTC P1631, or DTC P1632 for further diagnosis. |
| • | Check the fuel system for the following conditions: |
| - | Alcohol contaminants |
| - | Water |
| - | Foreign material |
| • | Check for a basic engine problem (low compression, timing chain ect.). |
| • | A scan tool can be used to energize the following items: |
| - | Fuel pump ON to check the fuel pump operation |
| - | Fuel injector to check for Ignition voltage at the fuel injector harness |
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
-
The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored in the scan tool for later reference.
-
Diagnosis of the DTCs that may be set could lead to the cause of the Cranks But Will Not Run condition.
-
The PCM grounds will only cause a problem if all the grounds are not making a good connection. If a PCM ground problem is suspected, the most probable place to check is where all the grounds meet at the engine block.
-
Locate and repair any shorts that may have caused the fuse to open before replacing the fuse.
-
A TP sensor that reads too high may cause an incorrect fueling condition.
-
An engine that has not been started should display ECT and IAT temperatures that are relatively close to each other. During the warmer weather, the IAT readings maybe slightly higher than the ECT readings.
-
This step looks for a normal barometer reading and a change in MAP sensor values while cranking the engine. This step verifies the MAP sensor can detect the change in the manifold pressure that occurs while cranking the engine. Compare any questionable barometer readings with readings from another vehicle.
-
While cranking the engine, the CKP Activity (7X reference) should increment to 255, then rollover to 0.
-
If the scan tool loses serial data only while cranking the engine, then the ignition switch is not sending voltage to the PCM while in the crank position.
-
Check for possible voltage loss to the PCM including the ignition switch itself.
-
The ignition positive voltage should be available at the ignition feed terminal (L) of the ICM 11 pin harness electrical connector, and the ground terminal (K) should be a good ground.
-
The CKP sensor core is a magnet and should be magnetized.
-
The CKP sensor should output a AC voltage near 1100-1300 mV as the crankshaft turns. It is possible to trigger the ICM with a voltage as low as 200 mV. If no voltage is produced, a poor CKP sensor electrical connection or a malfunctioning CKP sensor is indicated.
-
The test light connected to B+ simulates a reference signal to the PCM. A fuel injector test light can be installed and will blink for every other touch of the test light if the CKP Activity (7X reference) circuit, the PCM and the fuel injector driver circuits are all functioning properly.
-
If the test light illuminates while probing the CKP Activity (7X reference) circuit, then the CKP Activity (7X reference) circuit is shorted to ground. If the test light remains OFF and the CKP Activity Counter does not increment, then the CKP Activity (7X reference) circuit is open. If the CKP Activity Counter increment several counts, when the reference low (terminal H) is probed, then the CKP Activity (7X reference) is shorted to voltage.
-
Replacement PCMs must be reprogrammed and the crankshaft position system variation learn procedure must be performed. Refer to the latest Techline information for PCM programming and the Powertrain Control Module (PCM) for the Crankshaft Position System Variation Procedure .
-
Battery voltage should be available at the fuel injector ignition feed circuit whenever the fuel pump power feed circuit is switched ON and when the PCM is receiving ignition pulses, during engine cranking or when running. The ignition must be turned OFF for at least 10 seconds to assure that the PCM powers down and will then switch the fuel pump back ON for 2-3 seconds when the ignition is turned back ON.
-
By installing the spark plug jumper leads and testing for spark on all 4 plug wire leads, each ignition coil's ability to produced at least 25,000 volts is verified.
-
The fuel pump is turned ON by the PCM for 2-3 seconds after ignition is first turned ON. This step checks to see if the fuel pump and fuel pump relay are operating correctly and if the fuel pressure is within the proper range. Refer to the Fuel System Diagnosis for fuel pressure gauge installation procedure.
-
The ignition voltage is supplied to the fuel injectors and fuel pump for the first two seconds when the ignition switch is turned ON and continuously when the engine is cranked. If the fuel pump runs but the fuel injector test light did not blink, then the fuel injector ignition feed circuit is open between the fuel injector and the splice from the ignition feed circuit.
-
This step verifies that the PCM is sending a signal to the Ignition Control Module (ICM) to fire the ignition coils. If the test light blinks, then the signal is OK to this point and the no spark condition lies in the ignition coil electrical harness or the ignition coil that did not produce spark.
-
The ignition coil electrical harness can easily be checked by performing the previous step with the ignition coil electrical harness connected to the ICM. Check for a voltage and ground signal to the ignition coils at the coil electrical connector.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | |||||||||
Are DTC(s) P0335, P0601, P0602, or P1629 set? | -- | Go to applicable DTC table | ||||||||
Inspect the PCM ground connection at the engine block. Is the ground connection OK? | -- | |||||||||
4 | Inspect the following fuses:
Are the fuses OK? | -- | ||||||||
5 | Repair the PCM ground connection. Is the action complete? | -- | -- | |||||||
6 | Check the fuel level and add fuel if necessary. Was it necessary to add fuel? | -- | ||||||||
Is the action complete? | -- | -- | ||||||||
Does the TP sensor read less then the specified value? | 1.0 V | |||||||||
Is the Engine Coolant Temperature (ECT) relatively close to the Intake Air Temperature (IAT)? | -- | Go to DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage or DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage | ||||||||
Does the MAP sensor read over the specified value and then change while cranking the engine? | 4 V | |||||||||
Crank the engine. Does the CKP Activity Counter increment while cranking? | -- | |||||||||
Was Serial Data lost while cranking the engine? | -- | |||||||||
Repair the voltage loss to the PCM from the ignition switch. Is the action complete? | -- | -- | ||||||||
Does the DVM read the specified voltage? | B+ | |||||||||
15 |
Is the resistance reading within the specified value? | 500-900ohms | ||||||||
16 | Repair the open in the ground or in the ignition positive voltage circuit to the ICM. Is the action complete? | -- | -- | |||||||
Is the CKP sensor magnetic with undamaged terminals and the resistance within the specified value? | 500-900ohms | |||||||||
Is the voltage reading greater than the specified value? | 200 mV | |||||||||
Connect a test light to B+ and touch the ICM harness electrical connector G terminal and then the H terminal. Does the CKP Activity Counter increment one count as the test light touches terminal H? | -- | |||||||||
20 | Check for a poor electrical connection, open or a short in the CKP sensor electrical harness and repair as necessary. Was a repair necessary? | -- | -- | |||||||
21 | Replace the CKP sensor. Is the action complete? | -- | -- | |||||||
22 | Visually inspect the ICM harness electrical connector to see if the connections are clean and tight and repair if necessary. Was a repair necessary? | -- | ||||||||
Check the CKP activity (7X reference) circuit for an open or a short and repair as necessary. Was a repair necessary? | -- | |||||||||
24 | Replace the ICM. Is the action complete? | -- | -- | |||||||
Check for a poor electrical connection at the PCM, if OK replace the PCM. Is the action complete? | -- | -- | ||||||||
Does the test light blink? | -- | |||||||||
Does spark jump the spark tester on all 4 spark plug wires? | -- | |||||||||
Important: The ignition switch may have to be cycled more than one time to achieve the highest fuel pressure. Is the fuel pressure between the specified value? | 284-325 kPa (41-47 psi) | |||||||||
29 | Check for fouled spark plugs and replace if necessary. Was any spark plug replacement necessary? | -- | Go to Diagnostic Aids | |||||||
Repair the open in the fuel pump and fuel injector ignition feed circuit. Is the action complete? | -- | -- | ||||||||
31 |
Notice: Do not leave the jumper wire connected to the PCM IC circuit connector for longer than 5 seconds at a time. Failure to do so may damage the ignition coil and/or the Ignition Control Module. Does a spark jump on the spark tester? | -- | ||||||||
Does the test light blink while cranking the engine? | -- | |||||||||
Check for a malfunctioning ignition coil harness electrical connection or a open in the ignition coil harness and repair as necessary. Was a repair necessary? | -- | |||||||||
34 | Replace the ignition coil that did not spark. Is the action complete? | -- | -- | |||||||
35 | Check the ignition control circuit for an open or a short and repair as necessary. Was a repair necessary? | -- | ||||||||
36 |
Does the engine start and continue to run? | -- | ||||||||
37 |
Are any DTCs displayed that have not been diagnosed? | -- | Go to Applicable DTC table | System OK Refer to Diagnostic Aids |
Engine Cranks But Does Not Run Fuel Pump Circuit
Circuit Description
When the ignition is turned ON, the powertrain control module (PCM) turns ON the in-tank fuel pump. The pump will remain ON as long as the PCM is receiving ignition reference pulses from the electronic ignition control module (ICM). If there are no reference pulses, the PCM will shut OFF the fuel pump about 2-3 seconds after the ignition is turned ON, about 10 seconds after the reference pulses stop.
The fuel pump delivers fuel to the fuel rail and fuel injectors, then to the fuel pressure regulator, where the system pressure is controlled to 283-324 kPa (41-47 psi) with no manifold vacuum or 214-303 kPa (31-44 psi) at idle. Excess fuel is then returned to the fuel tank.
Improper Fuel System pressure will result in one or all of the following symptoms:
| • | Cranks But Will Not Run |
| • | DTC P0171 |
| • | DTC P0172 |
| • | DTC P1171 |
| • | DTC P0300 |
| • | Cuts out, may feel like an ignition problem |
| • | Poor fuel economy, loss of power |
| • | Hesitation |
Diagnostic Aids
An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Check for a poor connection or damaged harness. Inspect the PCM harness and connectors for the following items:
| • | Improper mating |
| • | Broken locks |
| • | Improperly formed or damaged terminals |
| • | Poor terminal to wire connections |
| • | Damaged harnesses |
Test Description
The number(s) below refer(s) to the step number(s) on the Diagnostic Table.
-
The Powertrain OBD System Check prompts you to complete some of the basic checks and to store the freeze frame and failure records data on the scan tool, if applicable. This creates an electronic copy of the data captured when this DTC set. The scan tool stores this data for later reference.
-
If the no start condition was due to an open fuse, locate and repair any shorts that may have caused the fuse to open before the replacement.
-
This step determines if the PCM can control the fuel pump. The PCM should energize the fuel pump relay and turn ON the fuel pump when commanded by the scan tool. If the engine is not cranking or running, the PCM should de-energize the relay and turn OFF the fuel pump after 2-3 seconds.
-
Jumpering the fuel pump feed terminal to the fuel pump relay ignition feed terminal verifies that the fuel pump relay ignition feed circuit, the fuel pump feed circuit, the fuel pump and fuel ground are all OK.
-
This step checks for an open in the fuel pump ground circuit.
-
Reprogram the replacement PCM and perform the crankshaft position system variation learning procedure. Refer to the latest Techline information for PCM programming and Powertrain Control Module (PCM) for the Crankshaft Position System Variation Learning Procedure.
-
This test will determine if a short to ground on the fuel pump feed circuit caused the fuse to open. Be sure to disconnect the fuel pump harness before the test in order to prevent a mis-diagnosis.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | |||
Inspect the fuel pump relay fuse. Is the fuse OK? | -- | |||
Does the in-tank fuel pump run when the fuel pump relay is commanded ON? | -- | Go to Fuel System Diagnosis | ||
Does the fuel pump run? | -- | |||
5 |
Does the test light illuminate? | -- | ||
6 | With a test light connected to ground, probe the ignition feed terminal to the fuel pump relay. Is the test light ON? | -- | ||
With a test light connected to B+, probe the ground terminal to the fuel pump relay. Is the test light ON? | -- | |||
8 | Check for an open or short to ground in the fuel pump control circuit and repair the circuit as necessary. Was a repair necessary? | -- | ||
9 |
Does the test light illuminate? | -- | ||
10 | Repair the open in the ignition feed circuit for the fuel pump relay. Is the action complete? | -- | -- | |
11 | Replace the fuel pump relay. Is the action complete? | -- | -- | |
12 | Repair the open ground circuit to the fuel pump relay. Is the action complete? | -- | -- | |
13 | Inspect the connections and the terminals at the PCM and repair the connections and the terminals as necessary. Was a repair necessary? | -- | ||
14 | With a test light connected to B+, probe the fuel pump ground circuit (body side). Does the test light illuminate? | -- | ||
15 | Repair the open fuel pump feed circuit. Is the action complete? | -- | -- | |
Replace the PCM. Is the action complete? | -- | -- | ||
17 | Check the fuel pump feed and ground circuits in the fuel pump harness for an open. Repair the fuel pump feed and ground circuits in the fuel pump harness as necessary. Was a repair necessary? | -- | ||
18 | Repair the open fuel pump ground circuit. Is the action complete? | -- | -- | |
19 | Replace the fuel pump. Is the action complete? | -- | -- | |
Does the test light illuminate? | -- | |||
21 | Repair the short to ground in the fuel pump feed circuit. Is the action complete? | -- | -- | |
22 | With the test light still connected to B+, probe the fuel pump relay ignition feed circuit terminal. Does the test light illuminate? | -- | ||
23 | Repair the short to ground in the fuel pump relay ignition feed circuit. Is the action complete? | -- | -- | |
24 | Check the fuel pump feed circuit in the fuel pump harness for a short to ground. Repair the fuel pump feed circuit in the fuel pump harness as necessary. Was a repair necessary? | -- | ||
25 |
Does the engine start and continue to run? | -- | ||
26 |
Check to see if any additional DTCs are set. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to applicable DTC table | System OK |
