Cruise Control Inoperative/Malfunctioning WO/ETC
Diagnostic Aids
Important: Perform the following in order to avoid misdiagnosis.
• Inspect for proper operation of brake lamps and clutch switch, if equipped. • Inspect for proper operation of the transmission range switch. • Inspect throttle linkage for mechanical binding which could cause the
system to malfunction. • Inspect cruise control cable adjustment, should have minimum slack. • EMI on the speed sensor signal circuit may cause erratic cruise control
operation.
Conditions for Enabling Cruise Control
The vehicle speed is greater than 40 km/h (25 mph).
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Cruise Control Schematics | ||||
1 | Did you perform the Cruise Control Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Does the test lamp illuminate? | -- | Go to Step 3 | Go to Step 30 |
3 | Probe the ignition positive voltage circuit of the cruise control module with a test lamp that is connected to the ground circuit of the cruise control module. Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 31 |
4 |
Does the test lamp illuminate on any of the circuits? | -- | Go to Step 14 | Go to Step 5 |
5 |
Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 15 |
6 |
Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 17 |
7 |
Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 18 |
8 | Probe the TCC/brake, cruise release signal circuit with a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | Go to Step 11 | Go to Step 9 |
9 | Press the brake pedal while monitoring the test lamp. Does the test lamp illuminate? | -- | Go to Step 21 | Go to Step 10 |
10 | Probe the stoplamp switch signal circuit with a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | Go to Step 22 | Go to Step 11 |
11 | Press the brake pedal while monitoring the test lamp. Does the test lamp illuminate? | -- | Go to Step 12 | Go to Step 23 |
12 | Probe the cruise engaged signal circuit with a DMM that is connected to a good ground. Does the voltage measure near the specified value? | B+ | Go to Step 13 | Go to Step 24 |
13 | Check the speedometer for proper operation. Does the speedometer operate properly? | -- | Go to Step 25 | Go to Symptoms - Instrument Panel, Gages and Console in Instrument Panel, Gages, and Console |
14 | Test the circuit that illuminated the test lamp for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 28 |
15 | Test the cruise control on/off signal circuit for an open, high resistance or short to ground and the set/coast, resume/accel signal circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 16 |
16 | Test the ignition positive voltage circuit of the cruise control switch for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 28 |
17 | Test the set/coast switch signal circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 28 |
18 | Test the resume/accelerate switch signal circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 28 |
19 | Test the TCC/ brake, cruise release signal circuit for an open or a high resistance . Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 26 |
20 | Test the TCC/ brake, cruise release signal circuit for an open or a high resistance between the CPP switch and the cruise control module. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 32 |
21 | Test the TCC/ brake, cruise release switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 26 |
22 | Test the stoplamp switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 26 |
23 | Test the stoplamp switch signal circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 26 |
24 | Test the cruise engaged signal circuit for an open, a high resistance, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 27 |
25 | Test the speed sensor circuit for an open or a high resistance between the PCM and cruise control module. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 29 |
26 | Inspect for poor connections at the harness connector of the stop lamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 33 |
27 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 34 |
28 | Inspect for poor connections at the harness connector of the cruise control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 35 |
29 | Inspect for poor connections at the harness connector of the cruise control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 36 | Go to Step 36 |
30 | Repair the ignition positive voltage circuit of the cruise control module. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 36 | -- |
31 | Repair the ground circuit of the cruise control module. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 36 | -- |
32 | Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the replacement? | -- | Go to Step 36 | -- |
33 |
Important: The PCM must be reprogrammed after replacement. Refer to Powertrain Control Module Programming in Engine Controls - 4.8L, 5.3L 6.0L. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 4.8L, 5.3L 6.0L. Did you complete the replacement? | -- | Go to Step 36 | -- |
34 | Replace the cruise control switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column - Tilt. Did you complete the replacement? | -- | Go to Step 36 | -- |
35 | Replace the cruise control module. Refer to Cruise Control Module Replacement . Did you complete the replacement? | -- | Go to Step 36 | -- |
36 | Operate the vehicle within the conditions for cruise control operation. Does the cruise control system operate correctly? | -- | System OK | Go to Step 2 |
Cruise Control Inoperative/Malfunctioning W/ETC
Diagnostic Aids
Important: Perform the following in order to avoid misdiagnosis.
• Inspect for proper operation of brake lamps and clutch switch, if equipped. • Inspect for proper operation of the transmission range switch. • EMI on the speed sensor signal circuit may cause erratic cruise control
operation.
Conditions for Enabling Cruise Control
The vehicle speed is greater than 40 km/h (25 mph).
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Cruise Control Schematics | |||
1 | Did you perform A Diagnostic System Check - Cruise Control? | Go to Step 2 | |
2 |
Does the test lamp illuminate on any of the circuits? | Go to Step 12 | Go to Step 3 |
3 |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 13 |
4 |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 15 |
5 |
Does the test lamp illuminate? | Go to Step 6 | Go to Step 16 |
6 | Probe the stop lamp switch signal circuit with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 19 | Go to Step 7 |
7 | Press the brake pedal while monitoring the test lamp. Does the test lamp illuminate? | Go to Step 8 | Go to Step 21 |
8 | Probe the brake switch signal circuit of the ECM harness connector with a test lamp connected to a good ground. Does the test lamp illuminate? | Go to Step 9 | Go to Step 11 |
9 | Press the brake pedal while monitoring the test lamp. Does the test lamp illuminate? | Go to Step 20 | Go to Step 10 |
10 | Check the speedometer for proper operation. Does the speedometer operate properly? | Go to Step 25 | Go to Symptoms - Instrument Panel, Gages and Console in Instrument Panel, Gages and Console |
11 |
Does the test lamp illuminate? | Go to Step 21 | Go to Step 22 |
12 | Test the circuit that illuminated the test lamp for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 24 |
13 | Test the on/off signal circuit for a open, high resistance or short to ground and the S/C and R/A signal circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 14 |
14 | Test the ignition positive voltage circuit of the cruise control switch for a open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 24 |
15 | Test the set/coast circuit for a open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 24 |
16 | Test the resume/accelerate circuit for a open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 24 |
17 | Test the stop lamp signal circuit for a open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 18 |
18 | Test the stop lamp ignition positive voltage circuit for a open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 23 |
19 | Test the stop lamp switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 23 |
20 | Test the brake switch circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 23 |
21 | Test the brake switch signal circuit of the PCM harness for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 23 |
22 | Repair the open in the ignition positive voltage circuit of the stop lamp switch. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 29 | -- |
23 | Inspect for poor connections at the harness connector of the stop lamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 27 |
24 | Inspect for poor connections at the harness connector of the cruise control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 28 |
25 | Inspect for poor connections at the harness connector of the Throttle Actuator Control (TAC) Module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 29 |
26 | Replace the Stop lamp switch. Refer to Stop Lamp Switch Replacement . Did you complete the replacement? | Go to Step 29 | -- |
27 | Replace the cruise control switch. Refer to Turn Signal and Multifunction Switch Assembly - Assemble - Off Vehicle in Steering Wheel and Column - Tilt. Did you complete the replacement? | Go to Step 29 | -- |
28 | Replace the Throttle Actuator Control (TAC) Module. Refer to Electronic Throttle Actuator Control Module Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L or Electronic Throttle Actuator Control Module Replacement in Engine Controls - 8.1L. Did you complete the replacement? | Go to Step 29 | -- |
29 | Operate the vehicle within the conditions for cruise control operation. Does the cruise control system operate correctly? | System OK | Go to Step 2 |
