P0593
P0593-SPEED CONTROL SWITCH 2 CIRCUIT HIGH
For a complete wiring diagram, refer to the Wiring Information.
- When Monitored:
With the ignition key on.
- Set Condition:
Speed control switch input above the maximum acceptable voltage at the PCM. One trip fault.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. ACTIVE DTC
1. 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 may result in possible serious or fatal injury.
NOTE: It may be necessary to test drive the vehicle and operate the speed control in order for this DTC to set.
2. With a scan tool, select View DTCs.
Is the DTC Active at this time?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. . Intermittent Condition Test
2. SPEED CONTROL SWITCHES
1. Turn the ignition off.
2. Remove and disconnect the Speed Control Switches from the steering wheel.
3. Measure the resistance across each Speed Control Switch.
4. Monitor the Ohmmeter while pressing each function button on each switch.
5. The following resistance specs are taken between terminals (V72) S/C Switch No.1 Signal and (V937) S/C Switch Ground circuit of the Switch when holding the switch button in the following position:
- Not pressing any switch - 20.5 kOhms
- On/Off - 0.47 kOhms
- Set - 5.49 kOhms
- Coast - 2.94 kOhms
- Cancel - 1.24 kOhms
- Resume/Accel - 15.4 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. (V72) S/C SIGNAL 2 CIRCUIT SHORTED TO VOLTAGE
1. Disconnect the C3 PCM harness connector.
2. Ignition on, engine not running.
3. Measure the voltage on the (V72) S/C Signal 2 circuit in the S/C Switch harness connector.
Is there any voltage present?
Yes
- Repair the short to voltage in the (V72) S/C Signal 2 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 4
4. (V72) S/C SIGNAL 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 PCM Pinout Box 8815 to perform diagnosis.
1. Turn the ignition off.
2. Measure the resistance of the (V72) S/C Signal 2 circuit from the Speed Control Switch to the appropriate terminal of PCM Pinout Box 8815.
Is the resistance below 5.0 Ohms for each measurement?
Yes
- Go To 5
No
- Repair the open in the (V72) S/C Signal 2 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
5. (V937) S/C SWITCH GROUND CIRCUIT OPEN
1. Measure the resistance of the (V937) S/C Switch Ground circuit from the S/C Switch harness connector to the appropriate terminals of PCM Pinout Box 8815.
Is the resistance below 5.0 Ohms for each measurement?
Yes
- Go To 6
No
- Repair the open in the (V937) S/C Switch Ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
6. SPEED CONTROL SWITCH VOLTAGE VALUES
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 PCM Pinout Box 8815 and PCM Pinout Box Adapter 8815-1 to perform diagnosis.
1. Using a voltmeter check the voltage on the (V38) S/C Signal 2 circuit at the appropriate terminal of the PCM Pinout Box 8815.
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 may result in possible serious or fatal injury.
2. Start the engine and allow it to reach normal operating temperature.
3. Monitor the voltmeter.
4. Allow the engine to idle.
5. With a scan tool, monitor the S/C Switch voltage readings.
6. Compare the voltage readings on the voltmeter to what the scan tool displayed.
Are the voltage readings out of the listed specification and is there less than a 0.2 of a volt difference between the voltmeter switch values and the scan tool switch value?
Yes
- Verify that there is good pin to terminal contact in the Switch and Powertrain Control Module connectors. If OK, replace the Speed Control Switch.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 7
7. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Speed Control Switch and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. 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.
4. Perform 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.