P0580

P0580-SPEED CONTROL SWITCH #1 LOW

P0580-Speed Control Switch #1 Low:

WHEN MONITORED:
With the ignition key on. Battery voltage above 10 volts.

SET CONDITION:
The PCM detects the Speed Control Switch Signal circuit voltage is less than 0.43. One Trip Fault.

POSSIBLE CAUSES
- Speed control switch
- (V71) S/C switch No. 1 signal circuit shorted to V937/K914 S/C switch return
- (V71) S/C switch No. 1 signal circuit shorted to ground
- PCM

Diagnostic Test

1. SPEED CONTROL SWITCH VOLTAGE LOW

Ignition on, engine not running.
With the scan tool in Sensors, read the S/C Switch Volts.

Q: Is the Speed Control voltage below 1.0 volt?

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 SWITCH

With the scan tool in Sensors, monitor the S/C Switch Volts.
Disconnect the Speed Control Switch harness connector.

Q: Did the voltage change to above 4.7 volts?

YES: Replace the Speed Control Switch. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 3




3. (V71) S/C SWITCH NO. 1 SIGNAL CIRCUIT SHORTED TO V937/K914 S/C SWITCH RETURN CIRCUIT

Turn the ignition off.
Disconnect the PCM harness connector.

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 between the V937/K914 S/C Switch Return circuit and the (V71) S/C Switch No. 1 Signal circuit in the Speed Control Switch harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Repair the (V71) S/C Switch No. 1 Signal circuit for a short to the V937/K914 S/C Switch Return circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 4




4. (V71) S/C SWITCH NO. 1 SIGNAL CIRCUIT SHORTED TO GROUND

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 between the (V71) S/C Switch No. 1 Signal circuit at the appropriate terminal of special tool #8815 and ground.

Q: Is the resistance below 5.0 ohms?

YES: Repair the (V71) S/C Switch No. 1 Signal circuit for a short to ground. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 5

5. PCM

NOTE: Before continuing, disconnect the PCM harness connector and check the related wiring terminals for corrosion, damage or terminal push out. Repair as necessary.

If there are no possible causes remaining, view repair.

Repair
Replace and program the Powertrain Control Module. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test