P0564-S/C SWITCH #1 SIGNAL CIRCUIT PLAUSIBILITY
For a complete wiring diagram Refer to Section 8W
- When Monitored:
With the ignition switch on and no other S/C Switch DTC's present.
- Set Condition:
The S/C Switch #1 signal voltage is not within a valid switch signal range.
| Possible Causes |
| SPEED CONTROL SWITCHES |
| S/C SWITCH SIGNAL CIRCUIT OPEN |
| S/C SWITCH SIGNAL CIRCUIT OPEN |
| S/C SWITCH SIGNAL CIRCUIT SHORT TO GROUND |
| S/C SWITCH SIGNAL CIRCUIT SHORTED TO VOLTAGE |
| SENSOR GROUND OPEN |
| ENGINE CONTROL MODULE |
Diagnostic Test
1. VERIFY S/C SWITCH SIGNAL CIRCUIT VOLTAGE
NOTE: 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.
NOTE: 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 harness connectors from both S/C Switches.
Turn the ignition on.
Measure the voltage of the S/C Switch #1 Signal circuit at both S/C Switch harness connectors.
Select the appropriate voltage reading.
4.5 to 5.5 volts at both connectors.
- Go To2
4.5 to 5.5 volts at only one connector.
- Repair the S/C Switch Signal circuit that measured below 4.5 volts for an open.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
Below 4.5 volts at both connectors.
- Go To4
Above 5.5 volts for either measurement.
- Go To6
2. SENSOR GROUND OPEN
Turn the ignition off.
Disconnect the ECM harness connectors.
Measure the resistance of the Sensor Ground circuit between each S/C Switch harness connector and the ECM harness connector.
Is the resistance below 10.0 ohms for each measurement?
Yes
- Go To3
No
- Repair the Sensor Ground circuit for an open.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
3. ECM - SENSOR GROUND OPEN
Connect the S/C Switch harness connectors.
With the scan tool, read the S/C Switch Voltage.
While monitoring the scan tool, connect a jumper wire between the S/C Switch #1 Signal circuit and the Sensor Ground circuit in the S/C Switch harness connector.
Does the scan tool display below 0.1 volt with the jumper wire connected?
Yes
- Replace the Speed Control Switches.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
No
- Replace and program the Engine Control Module in accordance with the Service Information.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
4. S/C SWITCH #1 SIGNAL CIRCUIT OPEN
Turn the ignition off.
Disconnect the ECM harness connectors.
Measure the resistance between the S/C Switch #1 Signal circuit between both S/C Switch harness connectors and the ECM harness connector.
Is the resistance below 10.0 ohms for both measurements?
Yes
- Go To5
No
- Repair the S/C Switch #1 Signal circuit that measured above 10.0 ohms for an open.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
5. S/C SWITCH #1 SIGNAL CIRCUIT SHORT TO GROUND
Measure the resistance between ground and the S/C Switch #1 Signal circuit.
Is the resistance above 1000 ohms?
Yes
- Replace and program the Engine Control Module in accordance with the Service Information.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
No
- Repair the S/C Switch #1 Signal circuit for a short to ground.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
6. S/C SWITCH #1 SIGNAL CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off.
Disconnect the ECM harness connectors.
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 S/C Switch #1 Signal circuit.
Is the voltage above 1.0 volt?
Yes
- Repair the S/C Switch #1 Signal circuit for a short to voltage.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
No
- Replace and program the Engine Control Module in accordance with the Service Information.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).