Cruise Control Inoperative/Malfunctioning L81
Diagnostic Aids
Caution: Refer to SIR Caution in the Preface section.
Disable the inflatable restraint steering wheel module when performing this diagnostic table. Refer to SIR Disabling and Enabling in SIR.
Ensure that the following cruise control switches are not stuck in the engaged position:
| • | On/Off switch |
| • | Set/Coast switch |
| • | Resume/Accel switch |
Perform the following in order to avoid misdiagnosis:
| • | Inspect for proper operation of the stop lamps. Refer to Exterior Lighting Systems Description and Operation in Wiring Systems. |
| • | Rotate the steering wheel to both steering stops and activate each cruise control switch separately. With a scan tool, observe the associated Cruise Control Switch parameter in the Idle/Speed Control data list. This will help eliminate the possibility of a internally open or shorted inflatable restraint steering wheel module coil. |
| • | EMI 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 in Wiring Systems. |
Step | Action | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Cruise Control Schematics Connector End View Reference: Engine Control Module Connector End Views in Engine Controls - 3.0L (L81) | |||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||||
2 |
Do all of the parameters listed above display OFF? | Go to Step 3 | Go to Step 6 | ||||||
3 |
Does the Cruise Switch parameter display ON? | Go to Step 4 | Go to Step 7 | ||||||
4 |
Does the Cruise Set/Coast parameter display ON? | Go to Step 5 | Go to Step 13 | ||||||
5 |
Does the Cruise Resume/Accel parameter display ON? | Go to Diagnostic Aids | Go to Step 14 | ||||||
6 |
Do all of the parameters listed above display OFF? | Go to Step 15 | Go to Step 9 | ||||||
7 |
Does the test lamp illuminate? | Go to Step 8 | Go to Step 17 | ||||||
8 |
Does the Cruise Switch parameter display ON? | Go to Step 15 | Go to Step 12 | ||||||
9 | Test the cruise control ON 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 20 | Go to Step 10 | ||||||
10 | Test the cruise control set/coast 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 20 | Go to Step 11 | ||||||
11 | Test the cruise control resume/accel 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 20 | Go to Step 16 | ||||||
12 | Test the cruise control ON switch signal circuit for an open, for a short to ground, or for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 16 | ||||||
13 | Test the cruise control set/coast switch signal circuit for an open, for a short to ground, or for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 15 | ||||||
14 | Test the cruise control set/coast switch signal circuit for an open, for a short to ground, or for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 15 | ||||||
15 | 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 20 | Go to Step 18 | ||||||
16 | Inspect for poor connections at the harness connector of the engine control module (ECM). 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 20 | Go to Step 19 | ||||||
17 | Repair the open, the short to ground, or the high resistance in the ignition 3 voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 20 | -- | ||||||
18 | Replace the cruise control switch. Refer to Steering Wheel Control Switch Assembly Replacement in Steering Wheel and Column. Did you complete the replacement? | Go to Step 20 | -- | ||||||
19 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 20 | -- | ||||||
20 |
Does the cruise control system operate properly? | System OK | Go to Step 2 | ||||||
