P0581

P0581-SPEED CONTROL SWITCH 1 CIRCUIT HIGH

For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.

- Set Condition:
The PCM detects that the input voltage is above the maximum acceptable value.

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

Diagnostic Test

1. DTC IS ACTIVE
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 can result in personal injury or death.

NOTE: It may be necessary to test drive the vehicle and operate the speed control in order for this DTC to set.

With a scan tool, select View DTCs.
Is the status Active for this DTC?

Yes

- Go to2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Checking For An Intermittent DTC

2. LEFT SPEED CONTROL SWITCH

Turn the ignition off.
Disconnect the Left Speed Control Switch harness connector.
Turn the ignition on.
With the scan tool, read the (V37) S/C Signal 1 input voltage.

NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus.1 volt) with the connector disconnected.

Turn the ignition off.
Connect a jumper wire between the (V37) S/C Signal 1 and the (K975) S/C Switch Ground circuit in the Left Speed Control Switch harness connector.
Turn the ignition on.
With the scan tool, read the (V37) S/C Signal 1 input voltage.

NOTE: The sensor voltage should be approximately 0.0 volts (plus or minus.1 volt) with the jumper wire in place.

Is the voltage on the scan tool displayed as described above?

Yes

- Replace the Left Speed Control Switch.
- Perform the PCM Verification Test.Powertrain Verification Test

No

- Go to3

3. RIGHT SPEED CONTROL SWITCH

Turn the ignition off.
Disconnect the Right Speed Control Switch harness connector.
Turn the ignition on.
With the scan tool, read the (V37) S/C Signal 1 input voltage.

NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus.1 volt) with the connector disconnected.

Turn the ignition off.
Connect a jumper wire between the (V37) S/C Signal 1 and the (K975) S/C Switch Ground circuit in the Right Speed Control Switch harness connector.
Turn the ignition on.
With the scan tool, read the (V37) S/C Signal 1 input voltage.

NOTE: The sensor voltage should be approximately 0.0 volts (plus or minus.1 volt) with the jumper wire in place.

Is the voltage on the scan tool displayed as described above?

Yes

- Replace the Right Speed Control Switch.
- Perform the PCM Verification Test.Powertrain Verification Test

No

- Go to4

4. (V37) S/C SIGNAL 1 CIRCUIT SHORTED TO VOLTAGE

Turn the ignition off.
Disconnect the Powertrain Control Module (PCM) connector.
Turn the ignition on.
Measure the voltage of the (V37) S/C Signal 1 circuit.
Is there any voltage present?

Yes

- Repair the (V37) S/C Signal 1 circuit for a short to voltage.
- Perform the PCM Verification Test.Powertrain Verification Test

No

- Go to 5

5. (V37) S/C SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE

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 (K975) S/C Switch Ground circuit between the Left Speed Control Switch harness connector and the appropriate terminal of special tool #8815 and between the Right Speed Control Switch harness connector and the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?

Yes

- Go to7

No

- Repair the (K975) S/C Switch Ground circuit for an open circuit or high resistance.
- Perform the PCM Verification Test.Powertrain Verification Test

7. POWERTRAIN CONTROL MODULE (PCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Left Speed Control Switch and the Powertrain Control Module (PCM) and the Right Speed Control Switch and the Powertrain Control Module (PCM).
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 PCM Verification Test.Powertrain Verification Test

No

- Replace the Powertrain Control Module (PCM).
- Perform the PCM Verification Test.Powertrain Verification Test