Cruise Control Inoperative/Malfunctioning 4.3L
Diagnostic Aids
To avoid a misdiagnosis, inspect for the following:
| • | Proper operation of brake lamps. Refer to Exterior Lighting Systems Description and Operation in Lighting Systems. |
| • | Proper operation of the clutch system, if equipped with a manual transmission. Refer to Clutch System Description and Operation in Clutch. |
| • | The throttle linkage is not binding. |
EMI on the vehicle 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). |
| • | The vehicle is not in PARK, REVERSE, NEUTRAL, or 1st gear. |
| • | The system voltage is between 12 volts and 16 volts. |
Step | Action | Value | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Cruise Control Schematics Connector End View Reference: Cruise Control Connector End Views or Powertrain Control Module Connector End Views in Engine Controls - 4.3L | ||||||||||
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 5 | ||||||
3 | Connect a test lamp between the ignition 3 voltage circuit and the ground circuit of the cruise control module. Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 22 | ||||||
4 |
Does the test lamp illuminate for any of the signal circuits listed above? | -- | Go to Step 12 | Go to Step 6 | ||||||
5 |
Does the test lamp illuminate for any of the signal circuits listed above? | -- | Go to Step 13 | Go to Step 21 | ||||||
6 |
Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 14 | ||||||
7 |
Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 16 | ||||||
8 |
Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 17 | ||||||
9 | Connect a test lamp between the stop lamp supply voltage circuit and a good ground. Refer to Circuit Testing in Wiring Systems. Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 19 | ||||||
10 | With a DMM, measure the voltage from the vehicle speed signal circuit to a good ground. Refer to Circuit Testing in Wiring Systems. Does the voltage measure at the specified value? | B+ | Go to Step 11 | Go to Step 20 | ||||||
11 | With a DMM, measure the voltage from the cruise control engaged signal to a good ground. Refer to Circuit Testing in Wiring Systems. Does the voltage measure at the specified value? | B+ | Go to Step 25 | Go to Step 18 | ||||||
12 | Test the signal circuit that illuminated the test lamp for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 29 | Go to Step 24 | ||||||
13 | Test the signal circuit that illuminated the test lamp for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 29 | Go to Step 24 | ||||||
14 | Test the cruise control on/off switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 29 | Go to Step 15 | ||||||
15 | Test the ignition 3 voltage circuit for an open or for a high resistance between S204 and the multifunction switch. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 29 | Go to Step 24 | ||||||
16 | Test the cruise control set/coast switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 29 | Go to Step 24 | ||||||
17 | Test the cruise control resume/accel switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 29 | Go to Step 24 | ||||||
18 | Test the cruise control engaged signal circuit for an open, for a high resistance, or for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 29 | Go to Step 23 | ||||||
19 | Repair the open, the high resistance, or the short to ground in the stop lamp supply voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 29 | -- | ||||||
20 | Repair the open or the high resistance in the vehicle speed signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 29 | -- | ||||||
21 | Repair the open, the high resistance, or the short to ground in the ignition 3 voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 29 | -- | ||||||
22 | Repair the open or the high resistance in the ground circuit of the cruise control module. 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 PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 29 | Go to Step 26 | ||||||
24 | Inspect for poor connections at the harness connector of the multifunction switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 29 | Go to Step 27 | ||||||
25 | Inspect for poor connections at the harness connector of the cruise control module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 29 | Go to Step 28 | ||||||
26 |
Important: Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 4.3L. Did you complete the replacement? | -- | Go to Step 29 | -- | ||||||
27 | Replace the multifunction switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column. Did you complete the replacement? | -- | Go to Step 29 | -- | ||||||
28 | Replace the cruise control module. Refer to Cruise Control Module Replacement . 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 | ||||||
Cruise Control Inoperative/Malfunctioning 4.8L, 5.3L, 6.0L, 8.1L
Diagnostic Aids
Perform the following in order to avoid a misdiagnosis:
| • | Inspect for proper operation of the brake lamps. Refer to Exterior Lighting Systems Description and Operation in Lighting Systems. |
| • | Electromagnetic interference (EMI) on the vehicle speed sensor signal circuit may cause erratic cruise control operation. |
For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Conditions for Enabling Cruise Control
| • | The vehicle speed is greater than 40 km/h (25 mph). |
| • | The vehicle is not in PARK, REVERSE, NEUTRAL, or 1st gear. |
| • | The system voltage is within 12-16 volts. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the center high mounted stop lamp (CHMSL) supply voltage/stop lamp supply voltage circuit for an open or for a high resistance between the stop lamp switch and the throttle actuator control (TAC) module.
-
This step tests the cruise control set/coast switch signal circuit for an open or for a high resistance.
-
This step tests the cruise control resume/accel switch signal circuit for an open or for a high resistance.
-
This step tests the ignition 3 voltage circuit for an open, for a short to ground, or for a high resistance.
-
DTCs will set in the powertrain control module (PCM) when you perform this table.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference : Cruise Control Schematics Connector End View Reference: Cruise Control Connector End Views and Powertrain Control Module Connector End Views in Engine Controls - 4.8L, 5.3L, and 6.0L | |||
1 | Did you perform the Diagnostic System Check - Cruise Control? | Go to Step 2 | |
2 |
Does the Cruise On/Off Switch parameter display Off? | Go to Step 4 | Go to Step 3 |
3 |
Does the Cruise On/Off Switch parameter display Off? | Go to Step 22 | Go to Step 13 |
4 |
Does the Cruise On/Off Switch parameter display On? | Go to Step 5 | Go to Step 11 |
5 |
Does the Cruise Set/Coast Switch parameter Display On? | Go to Step 6 | Go to Step 9 |
6 |
Does the Cruise Resume/Accel. Switch parameter Display On? | Go to Step 7 | Go to Step 10 |
7 | Do the stop lamps operate properly? | Go to Step 8 | Go to Stop Lamps Inoperative in Lighting Systems |
Does the Stoplamp Pedal Switch parameter Display Applied? | Go to Diagnostic Aids | Go to Step 21 | |
Does the Cruise Set/Coast Switch parameter Display On? | Go to Step 22 | Go to Step 19 | |
Does the Cruise Resume/Accel. Switch parameter Display On? | Go to Step 22 | Go to Step 20 | |
Does the test lamp illuminate? | Go to Step 12 | Go to Step 15 | |
12 |
Does the Cruise On/Off Switch parameter display On? | Go to Step 22 | Go to Step 18 |
13 | Test the cruise control on switch signal circuit for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 14 |
14 |
Does the Cruise On/Off Switch parameter display On? | Go to Step 24 | Go to Step 23 |
15 | Test the cruise control set/coast switch signal circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 16 |
16 | Test the cruise control resume/accel switch signal circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 17 |
17 | Test the cruise control on switch signal circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 25 |
18 | Test the cruise control on switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 23 |
19 | Test the cruise control set/coast switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 23 |
20 | Test the cruise control resume/accel switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 23 |
21 | Test the center high mounted stop lamp (CHMSL) supply voltage/stop lamp supply voltage circuit for an open or for a high resistance between the stop lamp switch and the TAC module. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 23 |
22 | Inspect for poor connections at the harness connector of the cruise control switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 26 |
23 | Inspect for poor connections at the harness connector of the TAC module. Refer to Testing for Intermittent Conditions and Poor Connections and to 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 PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 29 | Go to Step 28 |
25 | Repair the open, the high resistance, or the short to ground in the ignition 3 voltage circuit. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 29 | -- |
26 | Replace the cruise control switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column. Did you complete the replacement? | Go to Step 29 | -- |
27 | Replace the TAC module. Refer to Electronic Throttle Actuator Control Module Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L or to Electronic Throttle Actuator Control Module Replacement in Engine Controls - 8.1L. Did you complete the replacement? | Go to Step 29 | -- |
28 |
Important: Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L or to Powertrain Control Module Replacement in Engine Controls - 8.1L. Did you complete the replacement? | Go to Step 29 | -- |
Does the cruise control system operate properly? | System OK | Go to Step 2 | |
Cruise Control Inoperative/Malfunctioning 6.6L
Diagnostic Aids
To avoid a misdiagnosis, inspect for the following:
| • | Proper operation of the stop lamps. Refer to Exterior Lighting Systems Description and Operation in Lighting Systems. |
| • | Proper operation of the clutch system, if equipped with a manual transmission. Refer to Clutch System Description and Operation in Clutch. |
| • | The throttle linkage is not binding. |
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). |
| • | The vehicle is not in PARK, REVERSE, NEUTRAL, or 1st gear. |
| • | The system voltage is between 12 volts and 16 volts. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Cruise Control Schematics Connector End View Reference: Cruise Control Connector End Views or Engine Control Module Connector End Views in Engine Controls - 6.6L (LB7) or to Engine Control Module Connector End Views in Engine Controls - 6.6L (LLY) | |||
1 | Did you perform the Cruise Control Diagnostic System Check? | Go to Step 2 | |
2 |
Does the Cruise On/Off Switch parameter display Off? | Go to Step 3 | Go to Step 6 |
3 |
Does the Cruise On/Off Switch parameter display On? | Go to Step 4 | Go to Step 10 |
4 |
Does the Cruise Set/Coast Switch parameter display On? | Go to Step 5 | Go to Step 7 |
5 |
Does the Cruise Resume/Accel. Switch parameter display On? | Go to Step 9 | Go to Step 8 |
6 |
Does the test lamp illuminate? | Go to Step 11 | Go to Step 20 |
7 |
Does the Cruise Set/Coast Switch parameter display On? | Go to Step 20 | Go to Step 15 |
8 |
Does the Cruise Resume/Accel. Switch parameter display On? | Go to Step 20 | Go to Step 16 |
9 |
Does the TCC Cruise Brake Pedal parameter display Applied? | Go to Diagnostic Aids | Go to Step 17 |
10 |
Does the test lamp illuminate? | Go to Step 12 | Go to Step 18 |
11 | Test the cruise control on switch signal circuit for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 25 | Go to Step 21 |
12 | Test the cruise control on switch signal circuit for an open, for a high resistance or for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 25 | Go to Step 13 |
13 | Test the cruise control resume/accel switch signal circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 25 | Go to Step 14 |
14 | Test the cruise control set/coast switch signal circuit for a for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 25 | Go to Step 20 |
15 | Test the cruise control set/coast switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 25 | Go to Step 21 |
16 | Test the cruise control resume/accel switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 25 | Go to Step 21 |
17 | Test the TCC/Brake switch signal circuit for an open, for a high resistance, or for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 25 | Go to Step 19 |
18 | Repair the open, the high resistance, or the short to ground in the ignition 3 voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 25 | -- |
19 | Inspect for poor connections at the harness connector of the stop lamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 25 | Go to Step 22 |
20 | Inspect for poor connections at the harness connector of the cruise control switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 25 | Go to Step 23 |
21 | Inspect for poor connections at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 25 | Go to Step 24 |
22 | Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Lighting Systems. Did you complete the replacement? | Go to Step 25 | -- |
23 | Replace the multifunction turn signal lever. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column. Did you complete the replacement? | Go to Step 25 | -- |
24 |
Important: Program the replacement ECM. Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls - 6.6L (LB7) or to Engine Control Module Replacement in Engine Controls - 6.6L (LLY). Did you complete the replacement? | Go to Step 25 | -- |
25 | Operate the vehicle within the conditions for cruise control operation. Does the cruise control system operate properly? | System OK | Go to Step 2 |
