P0591-S/C SWITCH #2 SIGNAL CIRCUIT PLAUSIBILITY

For a complete wiring diagram Refer to Section 8WWhen Monitored:With the ignition switch on and no other S/C Switch DTC's present.Set Condition:The S/C Switch Signal #2 voltage is not within a valid switch signal range.

Possible Causes(V937) S/C SWITCH GROUND OPEN(V72) S/C SIGNAL #2 CIRCUIT OPEN(V72) S/C SIGNAL #2 CIRCUIT SHORT TO GROUND(V72) S/C SIGNAL #2 CIRCUIT SHORTED TO VOLTAGESPEED CONTROL SWITCHENGINE CONTROL MODULE

Diagnostic Test1. VERIFY S/C SIGNAL CIRCUIT VOLTAGE

KEYSIGNAL 1SIGNAL 2LO LIMITHI LIMITLO LIMITHI LIMITRELEASED4.494.564.494.56ON-OFF0.851.003.673.75SET3.293.391.301.45RESUME-ACCEL3.984.052.172.29CANCEL1.721.822.983.08

If the ECM detects and stores a DTC, the ECM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the scan tool at the same time the DTC is displayed.Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.Turn the ignition off.Disconnect the S/C Switch harness connector.Turn the ignition on.Measure the voltage of the (V72) S/C Signal #2 circuit at the S/C Switch harness connector.Select the appropriate voltage reading.4.5 to 5.5 volts.Go To2 Below 4.5 volts.Go To4 Above 5.5 volts.Go To62. (V937) S/C SWITCH GROUND OPEN

Turn the ignition off.Disconnect the ECM harness connectors.Measure the resistance of the (V937) S/C Switch Ground circuit between the S/C Switch harness connector and the ECM harness connector.Is the resistance below 10.0 ohms?YesGo To3NoRepair the (V937) S/C Switch Ground circuit for an open.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)3. ECM - SENSOR GROUND OPEN

Reconnect the S/C Switch harness connector.Turn the ignition on.With the scan tool, read the S/C Switch Voltage.While monitoring the scan tool, connect a jumper wire between the (V72) S/C Signal #2 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 with the jumper wire connected?YesReplace the Speed Control Switch.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace and program the Engine Control Module in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)4. (V72) S/C SIGNAL #2 CIRCUIT OPEN

Turn the ignition off.Disconnect the ECM harness connectors.Measure the resistance between of the (V72) S/C Signal #2 circuit between the S/C Switch harness connector and the ECM harness connector.Is the resistance below 10.0 ohms?YesGo To5NoRepair the (V72) S/C Signal #2 circuit for an open.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)5. (V72) S/C SIGNAL #2 CIRCUIT SHORT TO GROUND

Measure the resistance between ground and the (V72) S/C Signal #2 circuit at the S/C Switch harness connector.Is the resistance above 1000 ohms?YesReplace and program the Engine Control Module in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoRepair the (V72) S/C Signal #2 circuit for a short to ground.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)6. (V72) S/C SIGNAL #2 CIRCUIT SHORTED TO VOLTAGE

Turn the ignition off.Disconnect the ECM harness connectors.Remove the ASD Relay from the TIPM.Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay connector.Turn the ignition on.Measure the voltage of the (V72) S/C Signal #2 circuit at the S/C Switch harness connector.Is the voltage above 1.0 volt?YesRepair the (V72) S/C Signal #2 circuit for a short to voltage.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace and program the Engine Control Module in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)