Cruise Control Inoperative/Malfunctioning With Throttle Actuator Control
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 . |
| • | 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 .
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 9-16 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 E voltage circuit for an open, for a short to ground, or for a high resistance.
-
The 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 or Powertrain Control Module Connector End Views | |||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | 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 | ||||||
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 Wiring Repairs . 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 Wiring Repairs . 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 Wiring Repairs . 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 Wiring Repairs . 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 the following:
Refer to Circuit Testing and Wiring Repairs . 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 the following:
Refer to Circuit Testing and Wiring Repairs . 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 the following:
Refer to Circuit Testing and Wiring Repairs . 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 a high resistance between the stop lamp switch and the TAC module. Refer to Circuit Testing and Wiring Repairs . 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 Connector Repairs . 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 Connector Repairs . 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 Connector Repairs . Did you find and correct the condition? | Go to Step 29 | Go to Step 28 | ||||||
25 | Repair the following in the Ignition E voltage circuit:
Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you complete the repair? | Go to Step 29 | -- | ||||||
26 | Replace the multifunction switch. Refer to Turn Signal Multifunction Switch Replacement . Did you complete the replacement? | Go to Step 29 | -- | ||||||
27 | Replace the TAC module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 29 | -- | ||||||
28 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. 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 Without Throttle Actuator Control
Diagnostic Aids
To avoid a misdiagnosis, inspect for the following:
| • | Proper operation of the stop lamps--Refer to Exterior Lighting Systems Description and Operation . |
| • | Proper adjustment of the cruise control cable--Refer to Cruise Control Cable Adjustment . |
| • | The throttle linkage is not binding. |
Electromagnetic interference on the speed sensor signal circuit may cause erratic cruise control operation.
For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections .
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 9-16 volts. |
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Cruise Control Schematics Connector End View Reference: Cruise Control Connector End Views | ||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||
2 |
Does the test lamp illuminate? | -- | Go to Step 3 | Go to Step 24 | ||||||
3 | Connect a test lamp between the ignition 1 voltage circuit and the ground circuit of the cruise control module. Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 25 | ||||||
4 |
Does the test lamp illuminate for any of the signal circuits listed above? | -- | Go to Step 15 | Go to Step 5 | ||||||
5 |
Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 16 | ||||||
6 |
Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 20 | ||||||
7 |
Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 21 | ||||||
8 | Connect a test lamp between the torque converter clutch (TCC) brake switch/cruise control release switch signal circuit and a good ground. Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 23 | ||||||
9 |
Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 26 | ||||||
10 | With a DMM, measure the voltage of the cruise control engaged signal circuit. Does the voltage measure near the specified value? | 9 Volts | Go to Step 11 | Go to Step 22 | ||||||
11 | With a DMM, measure the voltage at the vehicle speed signal circuit. Does the voltage measure near the specified value? | 9 Volts | Go to Step 12 | Go to Step 13 | ||||||
12 |
Does the voltage measure near the specified value? | 9 Volts | Go to Diagnostic Aids | Go to Step 27 | ||||||
13 | Test the vehicle speed signal circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 28 | ||||||
14 | Test the cruise control inhibit signal circuit for the following:
Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 29 | ||||||
15 | Test the signal circuit that illuminated the test lamp for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 28 | ||||||
16 | Test the cruise control On switch signal circuit for the following:
Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 17 | ||||||
17 | Test the cruise control set/coast switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 18 | ||||||
18 | Test the cruise control resume/accel switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 19 | ||||||
19 | Test the ignition 1 voltage circuit of the cruise control switch for the following:
Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 28 | ||||||
20 | Test the cruise control set/coast switch signal circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 28 | ||||||
21 | Test the cruise control resume/accel switch signal circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 28 | ||||||
22 | Test the cruise control engaged signal circuit for the following:
Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 27 | ||||||
23 | Repair the open or the high resistance in the TCC brake switch/cruise control release signal circuit between the fuse block - underhood and the cruise control module. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 33 | -- | ||||||
24 | Repair the following in the ignition 1 voltage circuit of the cruise control module:
Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 33 | -- | ||||||
25 | Repair the open or the high resistance in the ground circuit of the cruise control module. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 33 | -- | ||||||
26 | Repair the open or the high resistance in the CHMSL supply voltage/stop lamp supply voltage circuit between the fuse block - underhood and the cruise control module. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | -- | 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 . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 30 | ||||||
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 . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 31 | ||||||
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 . Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 32 | ||||||
30 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 33 | -- | ||||||
31 | Replace the cruise control switch. Refer to Turn Signal Multifunction Switch Replacement . Did you complete the replacement? | -- | Go to Step 33 | -- | ||||||
32 | Replace the cruise control module. Refer to Control Module References for replacement, setup, and programming . Did you complete the replacement? | -- | Go to Step 33 | -- | ||||||
33 | 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 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 . |
| • | The throttle linkage is not binding. |
Electro magnetic interference (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: Engine Control Module Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | 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 Switch 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 . 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 . 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 . 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 . 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 . 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 . 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 . 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 E voltage circuit. Refer to Wiring Repairs . 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 . 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 . 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 engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs . 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 . Did you complete the replacement? | Go to Step 25 | -- |
23 | Replace the multifunction turn signal lever. Refer to Turn Signal Multifunction Switch Replacement . Did you complete the replacement? | Go to Step 25 | -- |
24 | Replace the ECM. Refer to Control Module References for replacement, setup, and programming. 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 |
