P0580

P0580-LOW VOLTAGE DETECTED AT THE SPEED CONTROL SWITCH

P0580 - Low Voltage Detected At The Speed Control Switch:

WHEN MONITORED
While the ignition is on

SET CONDITION
Speed control MUX switch below 1.0 volts for 5 seconds.

POSSIBLE CAUSES
- S/C Wiring harness observable problem
- S/C Switch (on/off)
- Clockspring shorted to ground
- S/C Switch (resume/accel)
- S/C Switch signal circuit shorted to ground
- S/C Signal circuit shorted to sensor ground
- ECM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. S/C SWITCH VOLTAGE BELOW 1.0 VOLT
Turn the ignition on.
With the scan tool, read the S/C Switch volts status in the ECM.

Q: Is the S/C Switch voltage below 1.0 volt?

YES: Go To 3
NO: Go To 2

2. S/C WIRING HARNESS OBSERVABLE PROBLEM
Turn the ignition off.
Using the Schematics as a guide, inspect the Wiring and Connectors.

Q: Were any problems found?

YES: Repair as necessary. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 3

3. S/C SWITCH (ON/OFF)
Turn the ignition off.
Disconnect the S/C ON/OFF Switch harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Turn the ignition on.
With the scan tool in Sensors, read the S/C Switch volts in the ECM.

Q: Did the S/C Switch volts change to 5.0 volts?

YES: Replace the S/C ON/OFF Switch. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 4

4. S/C SWITCH (RESUME/ACCEL)
Turn the ignition off.
Disconnect the S/C RESUME/ACCEL Switch harness connector.

NOTE: Check connectors - Clean/repair as necessary.

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

Q: Did the S/C Switch volts go above 4.0 volts?

YES: Replace the Resume/Accel Switch. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 5

5. CLOCKSPRING SHORTED TO GROUND





Turn the ignition off.
Disconnect the clockspring 6-way harness connector (instrument panel wiring side).
Turn the ignition on.
With the scan tool in Sensors, read the S/C Switch volts in the ECM.

Q: Did the S/C Switch volts change to 5.0 volts?

YES: Replace the Clockspring. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 6

6. S/C SWITCH SIGNAL CIRCUIT SHORTED TO GROUND





Turn the ignition off.
Disconnect the S/C ON/OFF Switch harness connector.
Disconnect the ECM harness connectors.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance between the S/C Switch Signal circuit and ground (B-) at S/C ON/OFF Switch harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Repair S/C Switch Signal Circuit for a short to ground. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 7

7. S/C SIGNAL CIRCUIT SHORTED TO SENSOR GROUND





Measure the resistance between the S/C Signal Circuit and the Sensor Ground Circuit at the ON/OFF switch harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Repair S/C Signal Circuit shorted to Sensor Ground. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Replace and program the ECM in accordance with the Service Information. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1