P0581

P0581 - Speed Control Switch 1, Circuit High

For wiring diagrams, refer to.

• When Monitored: With the engine running and battery voltage greater than 10 volts.

• Set Condition: The PCM detects that the sensor input voltage is more than the maximum acceptable value.

• Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure

Test Step 1 - DTC is Active

• Start the engine and allow it to idle for at least 60 seconds.

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.

• 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 to Test Step 2 => [ Test
Step 2 - Speed Control Signal 1 Voltage ]

No

• Refer to the checking for an intermittent DTC diagnostic procedure. Refer to => Non-DTC Based Diagnostics. Checking for an Intermittent DTC

Test Step 2 - Speed Control Signal 1 Voltage

Disconnect and isolate the battery negative (ground) cable before beginning steering wheel removal or installation. Allow the front airbag system capacitor to discharge for two minutes before removing the steering wheel or any front airbag system component. This will disable the front airbag system. Failure to disconnect the battery could result in accidental front airbag module deployment and possible personal injury.

Do not place a non-deployed airbag face down on a hard surface as the airbag will propel into the air if accidentally deployed, and could result in serious or fatal injury.

• Turn the ignition OFF.

• Remove the speed control switch.

• Connect a jumper wire between the speed control signal 1 circuit and the speed control switch ground circuit in the speed control switch harness connector.

• Turn the ignition ON.

• With a scan tool, read the speed control signal 1 voltage.

• The speed control signal 1 voltage should be less than.2 volts with the jumper wire in place.

Is the speed control signal 1 voltage more than 4.8 volts with the speed control switch connector disconnected and less than.2 volts with the jumper wire in place?

Yes

• Go to Test Step 6 => [ Test
Step 6 - Speed Control Switch ]

No

• Go to Test Step 3 => [ Test
Step 3 - Speed Control Signal 1 Circuit Shorted to Voltage ]

Test Step 3 - Speed Control Signal 1 Circuit Shorted to Voltage

• Turn the ignition OFF.

• Disconnect the PCM connector.

• Turn the ignition ON.

• Measure the voltage of the speed control signal 1 circuit in the speed control switch harness connector.

Is there any voltage present?

Yes

• Repair the speed control signal 1 circuit for a short to voltage.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Go to Test Step 4 => [ Test
Step 4 - Speed Control Signal 1 Circuit Open or High Resistance ]

Test Step 4 - Speed Control Signal 1 Circuit Open or High Resistance

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 speed control switch ground circuit between the speed control switch harness connector and the appropriate terminal of special tool #8815.

Is the resistance less than 5.0 ohms?

Yes

• Go to Test Step 7 => [ Test
Step 7 - PCM ]

No

• Repair the speed control switch ground circuit for an open or high resistance.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 6 - Speed Control Switch

• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the speed control switch and the PCM.

• Look for any chafed, pierced, pinched, or partially broken wires.

• Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related connectors.

• Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.

• Look for the data to change or for the DTC to reset during the wiggle test.

• Refer to any technical service bulletins that may apply.

Were any problems found?

Yes

• Repair as necessary.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Replace the speed control switch.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 7 - PCM

• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the speed control switch and the PCM.

• Look for any chafed, pierced, pinched, or partially broken wires.

• Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related connectors.

• Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.

• Look for the data to change or for the DTC to reset during the wiggle test.

• Refer to any technical service bulletins that may apply.

Were any problems found?

Yes

• Repair as necessary.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Replace and program the PCM.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test