Speed Control Switch 1 Circuit High (ETC)
P0581-SPEED CONTROL SWITCH 1 CIRCUIT HIGH (ETC)
For complete wiring diagrams refer to Diagrams/Electrical.
- 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.
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 POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
2. SPEED CONTROL SWITCHES
Turn the ignition off.
Remove and disconnect 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 (V37) S/C Switch No.1 Signal and (V937) S/C Switch Return circuits of the Switch when holding the switch button in the following position
Not pressing any switch - 20.5 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 POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
3. CLOCKSPRING/STEERING CONTROL MODULE
Disconnect the C1 and C3 Clockspring harness connector.
Measure the resistance of the (V937) Switch Return circuit between the C1 and C3 Clockspring harness connectors.
Measure the resistance of the (V37) S/C Switch No.1 Signal circuit between the Clockspring harness connectors.
Was the resistance above 5.0 ohms for either circuit?
Yes
- Replace the Clockspring.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 4
4. (V37) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Connect the Clockspring harness connectors.
Disconnect the C3 PCM harness connector.
Ignition on, engine not running.
Measure the voltage on the (V37) S/C Switch No.1 Signal circuit in the Speed Control harness connector.
Is the voltage above 5.2 volts?
Yes
- Repair the short to battery voltage in the (V37) S/C Switch No.1 Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 5
5. (V37) S/C SWITCH NO.1 SIGNAL CIRCUIT OPEN
NOTE: The measurement must be taken from both Speed Control Switch harness connectors.
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 (V37) S/C Switch No.1 Signal circuit from the Speed Control harness connector 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 (V37) S/C Switch No.1 Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
6. (V937) SWITCH RETURN CIRCUIT OPEN
NOTE: The measurement must be taken from both Speed Control Switch harness connectors.
Measure the resistance of the (V937) Switch Return circuit from the Speed Control harness connector 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 POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
7. 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 Miller Special Tool #8815 and #8815-1 to perform diagnosis.
Using a voltmeter check the voltage on the (V37) S/C Switch No.1 Signal circuit and the (V38) S/C Switch No.2 Signal circuit at the appropriate terminals of the special tool #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 can result in personal injury or death.
Start the engine and allow it to reach normal operating temperature.
Monitor the voltmeter.
Allow the engine to idle.
With a scan tool, monitor the S/C Switch voltage readings.
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
- Replace the Speed Control Switch.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 8
8. 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 POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Replace and program the Powertrain Control Module.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test