Start / Stop Switch: Testing and Inspection
Vehicle ON/OFF Switch Indicator Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The vehicle ON/OFF switch has a single LED that indicates the vehicle power mode. When the vehicle is in the OFF mode, the LED is not illuminated. Pressing and holding the vehicle ON/OFF switch for five seconds, without the brake pedal applied, will enter the Vehicle Service Mode and the blue LED will illuminate. With the vehicle OFF and the brake pedal applied, pressing the vehicle ON/OFF switch once, the vehicle will enter the Vehicle ON mode and the blue LED will illuminate.
The vehicle ON/OFF switch contains two individual switches that provides redundant switch inputs to both the body control module (BCM) and the keyless entry control module. The BCM supplies the vehicle ON/OFF switch a constant B+ signal. The BCM monitors this signal to determine if the switch is released or pressed. When the vehicle ON/OFF switch is not pressed, voltage on the signal circuit is pulled down through two resistors in the switch. When the vehicle ON/OFF switch is pressed, voltage on the signal circuit is pulled down through only one resistor, changing the voltage seen at the BCM and indicating that the vehicle ON/OFF switch is pressed.
The keyless entry control module monitors voltage on the switch is the same manner as the BCM, but monitors the second switch located in the vehicle ON/OFF switch.
Reference Information
Schematic Reference
Power Moding Schematics Power Moding Schematics
Connector End View Reference
Component Connector End Views Hybrid/EV Battery Pack X1
Description and Operation
Power Mode Description and Operation Power Mode
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Circuit/System Verification
1. Verify the blue LED illuminates when the S83 vehicle ON/OFF switch is pressed and held for at least 5 seconds, with the brake pedal released.
• If the blue LED does not illuminate
Refer to Circuit/System Testing.
• If the blue LED illuminates
2. All OK.
Circuit/System Testing
1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the S83 vehicle ON/OFF switch. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the low reference circuit terminal 4 and ground.
• If 10 ohms or greater
1. Vehicle OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Test for less than 1 V between the control circuit terminal 5 and ground.
• If 1 V of greater
1. Vehicle OFF, disconnect the harness connector at the K9 body control module, Vehicle in Service Mode.
2. Test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Test for less than 2 ohms in control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K9 body control module.
• If less than 1 V
4. Vehicle OFF, connect the harness connector at the S83 vehicle ON/OFF switch.
5. Vehicle in Service Mode, disconnect the harness connector at the S83 vehicle ON/OFF switch.
6. Verify a test lamp illuminates between the control circuit terminal 5 and ground.
• If the test lamp does not illuminate
1. Vehicle OFF, disconnect the harness connector at the K9 body control module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K9 body control module.
• If the test lamp illuminates
7. Test or replace the S83 vehicle ON/OFF switch.
Component Testing
1. Vehicle OFF, disconnect the harness at the S83 vehicle ON/OFF switch.
2. Connect a jumper wire between the S83 vehicle ON/OFF switch terminal 4 and ground.
3. Connect a 3 A fused jumper wire between the S83 vehicle ON/OFF switch terminal 5 and B+.
4. Verify the blue LED illuminates.
• If the LED does not illuminate
Replace the S83 vehicle ON/OFF switch.
• If the LED illuminates
5. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Ignition and Start Switch Replacement Service and Repair
* Control Module References Programming and Relearning for the BCM replacement, programming and setup