P0593
P0593-SPEED CONTROL SWITCH 2 CIRCUIT HIGH
For a complete wiring diagram Consult Diagrams/Electrical.
- When Monitored:
With the ignition key on.
- Set Condition:
Speed Control Switch No.2 input above the maximum acceptable voltage at the PCM. One trip fault.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview.
Diagnostic Test
1. ACTIVE DTC
Start the engine and allow it to idle for at least 60 seconds.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.
NOTE: It may be necessary to test drive the vehicle and operate the speed control in order for this DTC to set.
With a scan tool, select View DTCs.
Is the DTC Active at this time?
Yes
- Go To 2
No
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition.
2. SPEED CONTROL SWITCHES
Disconnect and remove the Speed Control Switches from the steering wheel.
Measure the resistance across each Speed Control Switch.
Monitor the ohmmeter while pressing each function button on each switch.
The following resistance specs are taken between terminals (V372) S/C Switch No.2 Signal and (V397) S/C Switch Return circuits of the Switch when holding the switch button in the following position.
Not pressing any switch - 20.5 kohms
On/Off - 8.87 kohms
Set - 0.825 kohms
Coast - 0.47 kohms
Cancel - 3.92 kohms
Resume/Accel - 1.87 kohms
Does the function on the Speed Control Switches have the correct resistance value?
Yes
- Go To 3
No
- Replace the Speed Control Switch that had the incorrect resistance value.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
3. STEERING COLUMN CONTROL MODULE
Disconnect the C1 and C3 Steering Column Control Module harness connectors.
Measure the resistance of the (V397) S/C Switch Return circuit between the C1 and C3 SCCM connections.
Measure the resistance of the (V372) S/C Switch No.2 Signal circuit between the C1 and C3 SCCM connections.
Was the resistance above 5.0 ohms for either circuit?
Yes
- Replace the Steering Column Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 4
4. (V372) SIGNAL NO.2 CIRCUIT SHORTED TO VOLTAGE
Measure the voltage on the (V372) S/C Signal No.2 circuit in the S/C Switch harness connector.
Ignition on, engine not running.
Is there any voltage present?
Yes
- Repair the short to voltage in the (V372) S/C Signal No.2 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 5
5. (V72) S/C SWITCH SENSE 2 CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off.
Disconnect the C3 PCM harness connector.
Ignition on, engine not running.
Measure the voltage on the (V72) S/C Switch Sense 2 circuit in the C1 SCCM harness connector.
Is there any voltage present?
Yes
- Repair the short to voltage in the (V72) S/C Switch Sense 2 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 6
6. (V372) S/C SWITCH NO.2 SIGNAL CIRCUIT OPEN
Turn the ignition off.
Measure the resistance of the (V372) S/C Switch No.2 Signal circuit from the both Switch harness connectors to the C3 SCCM harness connector.
Is the resistance below 5.0 ohms?
Yes
- Go To 7
No
- Repair the open in the (V372) S/C Switch No.2 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
7. (V72) S/C SWITCH SENSE 2 CIRCUIT OPEN
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.
Measure the resistance of the (V72) S/C Switch Sense 2 circuit from the C1 SCCM harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms for both measurements?
Yes
- Go To 8
No
- Repair the open in the (V72) S/C Switch Sense 2 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
8. (V397) S/C SWITCH RETURN CIRCUIT OPEN
Measure the resistance of the (V397) S/C Switch Return circuit from the both Switch harness connectors to the C3 SCCM harness connector.
Is the resistance below 5.0 ohms?
Yes
- Go To 9
No
- Repair the open in the (V397) S/C Switch Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
9. (V937) S/C SWITCH RETURN CIRCUIT OPEN
Measure the resistance of the (V937) S/C Switch Return circuit from the C1 SCCM harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms for both measurements?
Yes
- Go To 10
No
- Repair the open in the (V937) S/C Switch Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
10. POWERTRAIN CONTROL MODULE (PCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Speed Control Switch and the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Switch and Powertrain Control Module connectors.
Search for any Technical Service Bulletins that may apply.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.