Cruise Control Inoperative/Malfunctioning 4.3L, 5.0L and 5.7L
Diagnostic Aids
Important: Perform the following in order to avoid misdiagnosis.
• Inspect for proper operation of brake lamps. • 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 29 |
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 30 |
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 signal circuit with a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 19 |
9 | Press the brake pedal while monitoring the test lamp. Does the test lamp illuminate? | -- | Go to Step 20 | Go to Step 10 |
10 | 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 21 | 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 22 |
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 23 |
13 | Check the speedometer for proper operation. Does the speedometer operate properly? | -- | Go to Step 24 | Go to Symptoms - Instrument Panel, Gages and Console in Instrument Panel, Gages and Consoles |
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 35 | Go to Step 27 |
15 | Test the cruise control On signal circuit for an open, high resistance or short to ground, and the cruise control set/coast, resume/accelerate 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 35 | Go to Step 16 |
16 | Test the ignition positive voltage circuit of the cruise control switch for an 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 35 | Go to Step 27 |
17 | Test the cruise control set/coast 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 35 | Go to Step 27 |
18 | Test the cruise control resume/accelerate 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 35 | Go to Step 27 |
19 | Test the TCC/Brake 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 35 | Go to Step 25 |
20 | Test the TCC/Brake 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 35 | Go to Step 25 |
21 | 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 35 | Go to Step 25 |
22 | Test the stop lamp 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 35 | Go to Step 25 |
23 | 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 35 | Go to Step 26 |
24 | 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 35 | Go to Step 28 |
25 | 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 35 | Go to Step 31 |
26 | 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 35 | Go to Step 32 |
27 | 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 35 | Go to Step 33 |
28 | 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 35 | Go to Step 34 |
29 | 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 35 | -- |
30 | Repair the ground circuit of the cruise control module. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 35 | -- |
31 | Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the replacement? | -- | Go to Step 35 | -- |
32 |
Important: The PCM must be reprogrammed after replacement. Refer to Powertrain Control Module Programming in Engine Controls - 4.3L or to Powertrain Control Module Programming in Engine Controls - 5.7L in Engine Controls. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 4.3L or to Powertrain Control Module Replacement in Engine Controls - 5.7L. Did you complete the replacement? | -- | Go to Step 35 | -- |
33 | Replace the cruise control switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column. Did you complete the replacement? | -- | Go to Step 35 | -- |
34 | Replace the cruise control module. Refer to Cruise Control Module Replacement . Did you complete the replacement? | -- | Go to Step 35 | -- |
35 | 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 8.1L
Diagnostic Aids
Important: To avoid misdiagnosis, inspect for the following:
• Proper operation of stop lamps. Refer to
Exterior Lighting Systems Description and Operation
in Lighting Systems. • The throttle linkage is not binding.
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 9 volts and 16 volts. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Cruise Control Schematics | |||
1 | Did you perform the Cruise Control Diagnostic System Check? | Go to Step 2 | |
2 |
Does the Cruise On/Off Switch parameter display On and the Off? | Go to Step 3 | Go to Step 6 |
3 |
Does the Cruise Set/Coast Switch parameter display On and then Off? | Go to Step 4 | Go to Step 9 |
4 |
Does the Cruise Resume/Accel. Switch parameter display On and then Off? | Go to Step 5 | Go to Step 10 |
5 |
Does the Stoplamp Pedal Switch parameter display Applied? | Go to Step 16 | Go to Step 7 |
6 |
Does the test lamp illuminate? | Go to Step 8 | Go to Step 12 |
7 |
Does the test lamp illuminate? | Go to Step 11 | Go to Step 13 |
8 | Test the cruise control on switch signal circuit for an open, for a high resistance, for a short to ground, or 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 20 | Go to Step 15 |
9 | Test the cruise control set/coast switch signal circuit for an open, for a high resistance, for a short to ground, or 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 20 | Go to Step 15 |
10 | Test the cruise control resume/accelerate switch signal circuit for an open, for a high resistance, for a short to ground, or 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 20 | Go to Step 15 |
11 | Test the stop lamp switch signal circuit for an open, for a high resistance, for a short to ground, or 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 20 | Go to Step 14 |
12 | 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 20 | -- |
13 | Repair the open, the high resistance, or the short to ground in the battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 20 | -- |
14 | 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 20 | Go to Step 17 |
15 | 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 20 | Go to Step 18 |
16 | 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 20 | Go to Step 19 |
17 | Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the repair? | Go to Step 20 | -- |
18 | Replace the multifunction turn signal lever. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column. Did you complete the repair? | Go to Step 20 | -- |
19 | Replace the TAC module. Refer to Electronic Throttle Actuator Control Module Replacement in Engine Controls - 8.1L. Did you complete the replacement? | Go to Step 20 | -- |
20 | Operate the vehicle within the conditions for cruise control operation. Does the cruise control system operate properly? | System OK | Go to Step 2 |
Cruise Control Inoperative/Malfunctioning 6.5L
Diagnostic Aids
Important: To avoid misdiagnosis, inspect for the following:
• Proper operation of stop lamps. Refer to
Exterior Lighting Systems Description and Operation
in Lighting Systems. • The throttle linkage is not binding.
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 9 volts and 16 volts. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Cruise Control Schematics | |||
1 | Did you perform the Cruise Control Diagnostic System Check? | Go to Step 2 | |
2 |
Does the Cruise On/Off Switch parameter display On and the Off? | Go to Step 3 | Go to Step 7 |
3 |
Does the Cruise Set/Coast Switch parameter display On and then Off? | Go to Step 4 | Go to Step 11 |
4 |
Does the Cruise Resume/Accel. Switch parameter display On and then Off? | Go to Step 5 | Go to Step 12 |
5 |
Does the Stoplamp Pedal Switch parameter display closed? | Go to Step 6 | Go to Step 8 |
6 |
Does the TCC Cruise Brake Pedal parameter display Open? | Go to Step 20 | Go to Step 9 |
7 |
Does the test lamp illuminate? | Go to Step 10 | Go to Step 15 |
8 |
Does the test lamp illuminate? | Go to Step 13 | Go to Step 17 |
9 |
Does the test lamp illuminate? | Go to Step 14 | Go to Step 16 |
10 | Test the cruise control on switch signal circuit for an open, for a high resistance, for a short to ground, or 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 24 | Go to Step 19 |
11 | Test the cruise control set/coast switch signal circuit for an open, for a high resistance, for a short to ground, or 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 24 | Go to Step 19 |
12 | Test the cruise control resume/accelerate switch signal circuit for an open, for a high resistance, for a short to ground, or 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 24 | Go to Step 19 |
13 | Test the stop lamp switch signal circuit for an open, for a high resistance, for a short to ground, or 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 24 | Go to Step 18 |
14 | Test the TCC/Brake switch signal circuit for an open, for a high resistance, for a short to ground, or 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 24 | Go to Step 18 |
15 | Repair the open, the high resistance, or the short to ground in the ignition 3 voltage circuit of the cruise control switch. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 24 | -- |
16 | Repair the open, the high resistance, or the short to ground in the ignition 3 voltage circuit of the TCC/Brake switch. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 24 | -- |
17 | Repair the open, the high resistance, or the short to ground in the battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 24 | -- |
18 | 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 24 | Go to Step 21 |
19 | 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 24 | Go to Step 22 |
20 | 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 24 | Go to Step 23 |
21 | Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the repair? | Go to Step 24 | -- |
22 | Replace the multifunction turn signal lever. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column. Did you complete the repair? | Go to Step 24 | -- |
23 |
Important: Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 6.5L. Did you complete the replacement? | Go to Step 24 | -- |
24 | Operate the vehicle within the conditions for cruise control operation. Does the cruise control system operate properly? | System OK | Go to Step 2 |
