Diagnostic Aids
WARNING: This page is about a different variant/trim than selected.
If the high idle system is inoperative but the switch circuit works, inspect for the following conditions:
- The high idle switch option is not programmed-Refer to High Idle Switch Programming .
- There are DTCs set-Diagnose these first.
- There is a non-DTC fault in one of the following components or systems:
- The brake switch
- The clutch switch
- The vehicle speed sensor
High Idle Switch Diagnosis (with RPO UF3)
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 |
|
Go to Diagnostic Aids | Go to Step 3 |
| 3 | Does the high idle switch parameter indicate ON all the time? | Go to Step 4 | Go to Step 6 |
| 4 |
|
Go to Step 13 | Go to Step 5 |
| 5 |
|
Go to Step 11 | Go to Step 14 |
| 6 |
|
Go to Step 7 | Go to Step 8 |
| 7 | Probe the ground circuit of the high idle switch with a test lamp connected to battery voltage. Does the test lamp illuminate? |
Go to Step 9 | Go to Step 12 |
| 8 | Test the high idle signal circuit for an open or high resistance. Refer to Circuit Testing
and Wiring Repairs
. Did you find and correct the condition? |
Go to Step 15 | Go to Step 10 |
| 9 | Test for an intermittent and for a poor connection at the high idle switch. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
. Did you find and correct the condition? |
Go to Step 15 | Go to Step 13 |
| 10 | Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
. Did you find and correct the condition? |
Go to Step 15 | Go to Step 14 |
| 11 | Repair the short to ground in the high idle switch signal circuit. Refer to Wiring Repairs
. Did you complete the repair? |
Go to Step 15 | - |
| 12 | Repair the open or high resistance in the ground circuit of the high idle switch. Refer to Wiring Repairs
. Did you complete the repair? |
Go to Step 15 | - |
| 13 | Replace the high idle switch. Did you complete the replacement? |
Go to Step 15 | - |
| 14 | Replace the ECM. Refer to Control Module References
for replacement, setup, and programming. Did you complete the replacement? |
Go to Step 15 | - |
| 15 | Operate the system in order to verify the repair. Did you correct the condition? |
System OK | Go to Step 2 |