P0585

P0585-SPEED CONTROL SWITCH 1 2 CORRELATION





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition on and no other S/C Switch DTCs present.

- Set Condition:
The (V71) S/C Switch No. 1 Signal and (V72) S/C Switch No. 2 Signal do not indicate the same S/C Switch position.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

Diagnostic Test

1. S/C SWITCH VOLTAGES OUT OF RANGE




Turn the ignition on.
With the scan tool, monitor the S/C Switch signal voltages.
Press each button while noting the voltage readings for each circuit.
Do the S/C Switch voltages fall within the ranges specified in the table when each button is pressed?

Yes

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Intermittent Condition

No

- Go To2

2. SPEED CONTROL SWITCH CIRCUIT OPEN OR HIGH RESISTANCE




Turn the ignition off.
Disconnect the Speed Control Switch harness connector.
Disconnect the Engine Control Module (ECM) harness connector.
Measure the resistance of the (V71) S/C Switch No. 1 Signal circuit between each Speed Control Switch harness connector and the Engine Control Module (ECM) harness connector.
Measure the resistance of the (V72) S/C Switch No. 2 Signal circuit between each Speed Control Switch harness connector and the Engine Control Module (ECM) harness connector.
Measure the resistance of the (V937) S/C Switch Ground circuit between each Speed Control Switch harness connector and the Engine Control Module (ECM) harness connector.
Is the resistance below 10.0 ohms for ALL measurements?

Yes

- Go To3

No

- Repair the Speed Control Switch circuit for an open circuit or high resistance.
- Perform the ECM Verification Test Ver. 1. Verification Tests

3. SPEED CONTROL SWITCH CIRCUIT SHORTED TO VOLTAGE




Turn the ignition off.
Remove the ASD Relay from the PDC.
Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay connector.
Turn the ignition on.
Measure the voltage of the (V71) S/C Switch No. 1 Signal circuit.
Measure the voltage of the (V72) S/C Switch No. 2 Signal circuit.
Measure the voltage of the (V937) S/C Switch Ground circuit.
Is there any voltage present on any of the circuits?

Yes

- Repair the Speed Control Switch circuit for a short to voltage.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Go to 4

4. SPEED CONTROL SWITCH CIRCUIT SHORTED TO GROUND




Turn the ignition off.
Remove the jumper wire and install the ASD relay.
Measure the resistance between ground and the (V71) S/C Switch No. 1 Signal circuit.
Measure the resistance between ground and the (V72) S/C Switch No. 2 Signal circuit.
Is the resistance above 1000 ohms?

Yes

- Go to 5

No

- Repair the Speed Control Switch circuit for a short to ground.
- Perform the ECM Verification Test Ver. 1. Verification Tests

5. SPEED CONTROL SWITCHES




Turn the ignition off.
Connect the Engine Control Module (ECM) harness connector.
Turn the ignition on.
With the scan tool, monitor the S/C Switch Voltage.
While monitoring the scan tool, connect a jumper wire between the (V71) S/C Switch No. 1 Signal circuit and the (V937) S/C Switch Ground circuit in the S/C Switch harness connector.
While monitoring the scan tool, connect a jumper wire between the (V72) S/C Switch No. 2 Signal circuit and the (V937) S/C Switch Ground circuit in the S/C Switch harness connector.
Does the scan tool display below 0.1 volt for each circuit with the jumper wire in place?

Yes

- Replace the Speed Control Switches.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Go to 6

6. ENGINE CONTROL MODULE (ECM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Speed Control Switch and the Engine Control Module (ECM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Replace the Engine Control Module (ECM).
- Perform the ECM Verification Test Ver. 1. Verification Tests