P0593
P0593-SPEED CONTROL SWITCH 2 CIRCUIT HIGH
For a complete wiring diagram refer to 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.
Diagnostic Test
1. SPEED CONTROL SWITCH VOLTAGE HIGH
NOTE: Do not press any of the Speed Control Switch buttons.
Ignition on, engine not running.
With a scan tool, read the Speed Control voltage.
Is the Speed Control voltage above 4.8 volts?
Yes
- Go To 2
No
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
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 (V38) S/C Switch No.2 Signal and (V937) S/C Switch Return circuits of the Switch when holding the switch button in the following position.
Not pressing any switch - 20.5k ohms
On/Off - 8.87k ohms
Set - 0.825k ohms
Coast - 0.47k ohms
Cancel - 3.92k ohms
Resume/Accel - 1.87k ohms
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. CLOCKSPRING
Disconnect the C1 and C3 Clockspring harness connectors.
Measure the resistance of the (V937) Switch Return circuit between the upper and lower clockspring harness connectors.
Measure the resistance of the (V38) S/C Switch No.2 Signal circuit between the C1 and C3 Clockspring harness connectors.
Was the resistance above 5.0 ohms for either circuit?
Yes
- Replace the clockspring.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 4
4. (V38) SIGNAL NO.2 CIRCUIT SHORTED TO BATTERY VOLTAGE
Connect the C1 and C3 Clockspring harness connectors.
Disconnect the C3 PCM harness connector.
Measure the voltage on the (V38) S/C Signal No.2 circuit in the Speed Control harness connector.
Ignition on, engine not running.
Is the voltage above 5.2 volts?
Yes
- Repair the short to battery voltage in the (V38) S/C Signal No.2 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 5
5. (V38) S/C SWITCH NO.2 SIGNAL CIRCUIT OPEN
Turn the ignition off.
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 (V38) S/C Switch No.2 Signal circuit from the both Switch harness connectors to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go To 6
No
- Repair the open in the (V38) S/C Switch No.2 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
6. (V937) SWITCH RETURN CIRCUIT OPEN
Measure the resistance of the (V937) Switch Return circuit from the both Switch harness connectors to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go To 7
No
- Repair the open in the (V937) Switch Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
7. PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
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