P0593

P0593-SPEED CONTROL SWITCH 2 CIRCUIT HIGH





For a complete wiring diagram Refer to Diagrams/Electrical.


- When Monitored:
Key on or Engine running.

- Set Condition:
Speed Control MUX switch above 11.5 volts for 5 seconds.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview


Diagnostic Test


1. SCAN TOOL SHOWS SPEED CONTROL SWITCH ON/OFF
Turn the ignition on.
With the scan tool in Inputs/Outputs, read the Speed Control inputs state in ECM.
While monitoring the scan tool, push the Speed Control On/Off Switch several times, then leave it on.
Did the scan tool show Speed Control Switch off and on?

Yes


- Go To 2


No


- Test Complete.



2. S/C WIRING HARNESS OBSERVABLE PROBLEM
Turn the ignition off.
Using the Schematics as a guide, inspect the Wiring and Connectors.
Were any problems found?

Yes


- Repair as necessary.
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test


No


- Go To 3



3. STEERING COLUMN CONTROL MODULE








Disconnect the C1 and C3 SCCM harness connectors.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the (V937) S/C Switch Return circuit between the C1 and C3 SCCM harness connectors.
Measure the resistance of the (V38) S/C Switch 2 Signal circuit between the C1 and C3 SCCM harness connectors.
Was the resistance above 5.0 ohms for either circuit?

Yes


- Replace the Steering Column Control Module.
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test


No


- Go To 4



4. SPEED CONTROL ON/OFF SWITCH
Disconnect the Speed Control On/Off Switch harness connector only.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance across the S/C On/Off Switch.
Is the resistance between 20.3K and 20.7K ohms?

Yes


- Go To 5


No


- Replace the On/Off Switch.
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test



5. (V38) S/C SWITCH 2 SIGNAL CIRCUIT SHORTED TO VOLTAGE
Turn the ignition on.
Measure the voltage of the (V38) S/C Switch 2 Signal circuit at both S/C Switch harness connectors.
Is the voltage above 6.0 volts?

Yes


- Repair the (V38) S/C Switch 2 Signal circuit for a short to voltage.
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test


No


- Go To 6



6. (V38) S/C SWITCH 2 SIGNAL CIRCUIT OPEN ECM TO SCCM
Turn the ignition off.
Disconnect the ECM harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the (V38) S/C Switch Signal 2 circuit between the ECM connector and the C1 SCCM harness connector.
Is the resistance below 5.0 ohms?

Yes


- Go To 7


No


- Repair open in the (V38) S/C Switch 2 Signal circuit between the ECM and the SCCM.
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test



7. (V38) S/C SWITCH 2 SIGNAL CIRCUIT OPEN SCCM TO S/C SWITCH
Measure the resistance of the (V38) S/C Switch 2 Signal circuit from the C3 SCCM harness connector to the S/C Switch harness connectors.
Is the resistance below 5.0 ohms?

Yes


- Go To 8


No


- Repair the open in the (V38) S/C Switch 2 Signal circuit between the Steering Column Control Module and the S/C switches.
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test



8. (V937) S/C SWITCH RETURN CIRCUIT OPEN BETWEEN THE SCCM AND S/C SWITCHES
Measure the resistance of the (V937) S/C Switch Return circuit between the S/C harness connectors to the C3 SCCM harness connector.
Is the resistance below 5.0 ohms?

Yes


- Go To 9


No


- Repair open in the (V937) S/C Switch Return circuit from Steering Column Control Module to the S/C switches.
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test



9. (V937) S/C SWITCH RETURN CIRCUIT OPEN BETWEEN THE ECM AND SCCM
Measure the resistance of the (V38) S/C Switch Return circuit between the ECM harness connector and the C1 SCCM harness connector.
Is the resistance below 5.0 ohms?

Yes


- Replace and program the ECM.
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test


No


- Repair open in the (V937) S/C Switch Return circuit between the ECM and Steering Column Control Module.
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test