Ignition Mode Switch Indicator Malfunction
Ignition Mode 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 ignition mode switch has two LED's that indicate the vehicle power mode. When the vehicle is in the off mode, both LED's will be off. Pressing the ignition mode switch button once (without the brake pedal applied), the vehicle enters the accessory mode and the amber LED (ACCESSORY) will illuminate. The accessory mode has a 5 min timeout to reduce battery drain. With the ignition OFF, pressing and holding the push button start switch for at least 10 s will place the vehicle in run/start mode (without the vehicle running) and the green LED (RUN/START) will illuminate. With the ignition OFF (with the brake pedal applied), pressing the ignition mode switch button once, the vehicle will enter run/start mode and the green LED (RUN/START) will illuminate. This will start the engine. With the engine running and while the vehicle is in P (Park), pressing the ignition mode switch once will turn the ignition OFF. If the vehicle is not in Park, the ignition will return to ACCESSORY and display the message SHIFT TO PARK in the Driver Information Center. When the vehicle is shifted into Park, the ignition system will then switch to OFF. Both LED's have the voltage supplied from the body control module (BCM). The ignition mode switch sends the ignition mode switch status to the keyless entry control module and to the BCM. The keyless entry control module sends a redundant signal to the BCM with the ignition mode switch status.
Reference Information
Schematic Reference
* Power Distribution Schematics Power Distribution Schematics
* Power Moding Schematics Power Moding Schematics
Connector End View Reference
Component Connector End Views Sunshade - Left
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 Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the green LED turns ON and OFF when commanding the Run/Start Power Mode Indicator On and Off with the scan tool.
• If the green LED does not turn ON and OFF
Refer to Circuit/System Testing - Green LED Test.
• If the green LED turns ON and OFF
3. Verify the amber LED turns ON and OFF when commanding the Accessory Power Mode Indicator On and Off with the scan tool.
• If the amber LED does not turn ON and OFF
Refer to Circuit/System Testing - Amber LED Test.
• If the amber LED turns ON and OFF
4. All OK.
Circuit/System Testing
Green LED Test
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S38 Ignition Mode Switch. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 4 and ground.
• If 10 ohms or greater
1. Ignition 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 connections.
• If less than 10 ohms
3. Connect the harness connector at the S38 Ignition Mode Switch.
4. Ignition ON, disconnect the harness connector at the S38 Ignition Mode Switch.
5. Test for less than 1 V between control circuit terminal 5 and ground while commanding Run/Start Power Mode Indicator Off with the scan tool.
• If 1 V or greater
1. Disconnect the harness connector at the K9 Body Control Module.
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, replace the K9 Body Control Module.
• If less than 1 V
6. Test for greater than 3 V between the control circuit terminal 5 and ground while commanding Run/Start Power Mode Indicator On with the scan tool.
• If 3 V or less
1. Ignition 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 3 V or greater
7. Test or replace the S38 Ignition Mode Switch.
Amber LED Test
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S38 Ignition Mode Switch. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 4 and ground.
• If 10 ohms or greater
1. Ignition 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 connections.
• If less than 10 ohms
3. Connect the harness connector at the S38 Ignition Mode Switch.
4. Ignition ON, disconnect the harness connector at the S38 Ignition Mode Switch.
5. Test for less than 1 V between control circuit terminal 2 and ground while commanding Accessory Power Mode Indicator Off with the scan tool.
• If 1 V or greater
1. Disconnect the harness connector at the K9 Body Control Module.
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, replace the K9 Body Control Module.
• If less than 1 V
6. Test for greater than 3 V between the control circuit terminal 2 and ground while commanding Accessory Power Mode Indicator On with the scan tool.
• If 3 V or less
1. Ignition 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 3 V or greater
7. Test or replace the S38 Ignition Mode Switch.
Component Testing
1. Ignition OFF, disconnect the harness at the S38 Ignition Mode Switch.
2. Connect a jumper wire between the S38 Ignition Mode Switch terminal 4 and ground.
3. Connect a 3 A fused jumper wire between the S38 Ignition Mode Switch terminal 5 and B+.
4. Verify the green LED illuminates.
• If the LED does not illuminate
Replace the S38 Ignition Mode Switch.
• If the LED illuminates
5. Connect a 3 A fused jumper wire between the S38 Ignition Mode Switch terminal 2 and B+.
6. Verify the amber LED illuminates.
• If the LED does not illuminate
Replace the S38 Ignition Mode Switch.
• If the LED illuminates
7. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Ignition and Start Switch Replacement (Without BTM) Ignition and Start Switch Replacement (Without BTM)Ignition and Start Switch Replacement (With BTM) Ignition and Start Switch Replacement (With BTM)
* Control Module References Control Module References for body control module replacement, programming and setup.