Power Mode Mismatch

Power Mode Mismatch

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.

Circuit/System Description

The body control module (BCM) controls the ignition main relay through the control circuit by applying voltage to the ignition main relay control circuit. The ignition main relay is energized when the ignition switch is in the ACCESSORY or the ON position.

Diagnostic Aids

A short to voltage on the ignition main relay coil control will cause the engine to remain running after the mode is changed to OFF.

Reference Information

Schematic Reference

* Power Distribution Schematics Power Distribution Schematics

* Power Moding Schematics Power Moding Schematics

Connector End View Reference

Component Connector End Views Outside Rearview Mirror - Driver

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 that the device turns on and off when commanding the appropriate ignition relay ON and OFF with a scan tool.

• If the KR73 ignition main relay does not change

Refer to Circuit/System Testing - Diagnostic A.

• If the KR72B ignition 1 relay does not change

Refer to Circuit/System Testing - Diagnostic B.

• If the KR75 engine controls ignition relay does not change

Refer to Circuit/System Testing - Diagnostic C.

• If the KR76 retained accessory power relay does not change

Refer to Circuit/System Testing - Diagnostic D.

• If the ignition relay's change

3. All OK.

Circuit/System Testing

Diagnostic A

1. Ignition OFF and all vehicle systems OFF, disconnect the KR73 ignition main relay. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 10 ohms between the ground circuit terminal 85 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 connection.

• If less than 10 ohms

3. Ignition ON.

4. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.

• If the test lamp does not illuminate and the circuit fuse is OK

1. Ignition OFF.

2. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, verify the fuse is OK and there is voltage at the fuse.

• If the test lamp does not illuminate and the circuit fuse is open

1. Ignition OFF. repair the short to ground on the circuit

2. Test for infinite resistance between the ignition circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the KR73 ignition main relay.

• If the test lamp illuminates

5. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.

6. Verify the test lamp turns ON and OFF when commanding the run/crank relay ON and OFF with a scan tool.

• If the test lamp is always OFF

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 the test lamp is always ON

1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.

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 the test lamp turns ON and OFF

7. Verify that a test lamp does not illuminate between the ignition circuit terminal 87and ground.

• If the test lamp illuminates

Repair the short to voltage on the ignition circuit.

• If the test lamp does not illuminate

8. Ignition ON, connect a 3 A fused jumper wire between the B+ circuit terminal 30 and the ignition control circuit terminal 87.

9. Verify the device is activated.

• If the device does not activate

1. Ignition OFF, disconnect the harness connector at the device.

2. Test for infinite resistance between the ignition 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 ignition circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the device.

• If the device activates

10. Test or replace the KR73 ignition main relay.

Diagnostic B

1. Ignition OFF and all vehicle systems OFF, disconnect the KR72B ignition 1 relay. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 10 ohms between the ground circuit terminal 85 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 connection.

• If less than 10 ohms

3. Ignition ON.

4. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.

• If the test lamp does not illuminate and the circuit fuse is OK

1. Ignition OFF.

2. Test for less than 2 ohms in the ignition circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, verify the fuse is OK and there is voltage at the fuse.

• If the test lamp does not illuminate and the circuit fuse is open

1. Ignition OFF. repair the short to ground on the circuit

2. Test for infinite resistance between the ignition circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the KR72B ignition 1 relay.

• If the test lamp illuminates

5. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.

6. Verify the test lamp turns ON and OFF when commanding the relay ON and OFF with a scan tool.

• If the test lamp is always OFF

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 the test lamp is always ON

1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.

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 the test lamp turns ON and OFF

7. Verify that a test lamp does not illuminate between the ignition circuit terminal 87 and ground.

• If the test lamp illuminates

Repair the short to voltage on the ignition circuit

• If the test lamp does not illuminate

8. Ignition ON, connect a 3 A fused jumper wire between the B+ circuit terminal 30 and the ignition circuit terminal 87.

9. Verify device is activated.

• If the device does not activate

1. Ignition OFF, disconnect the harness connector at the device.

2. Test for infinite resistance between the ignition 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 ignition circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the device.

• If the device activates

10. Test or replace the KR72B ignition 1 relay.

Diagnostic C

1. Ignition OFF and all vehicle systems OFF, disconnect the KR75 engine controls ignition relay, ignition ON.

2. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.

• If the test lamp does not illuminate and the circuit fuse is good

1. Ignition OFF.

2. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.

• If the test lamp does not illuminate and the circuit fuse is open

1. Ignition OFF.

2. Test for infinite resistance between the B+ circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, test or replace the KR75 engine controls ignition relay.

• If the test lamp illuminates

3. Verify a test lamp illuminates between the B+ circuit terminal 86 and ground.

• If the test lamp does not illuminate and the circuit fuse is good

1. Ignition OFF.

2. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If the test lamp illuminates

4. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.

5. Verify the test lamp turns ON and OFF when commanding the engine controls ignition relay ON and OFF with a scan tool.

• If the test lamp is always OFF

1. Ignition OFF, disconnect the harness connector at the K20 engine control module, ignition ON.

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. Ignition OFF.

4. 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 K20 engine control module.

• If the test lamp is always ON

1. Ignition OFF, disconnect the harness connector at the K20 engine 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, replace the K20 engine control module.

• If the test lamp turns ON and OFF

6. Verify a test lamp does not illuminate between the ignition circuit terminal 87 and ground.

• If the test lamp illuminates

Repair the short to voltage on the circuit.

• If the test lamp does not illuminate

7. Ignition ON, connect a 3 A fused jumper wire between the B+ circuit terminal 30 and the ignition circuit terminal 87.

8. Verify device is activated.

• If the device does not activate

1. Ignition OFF, disconnect the harness connector at the device.

2. Test for infinite resistance between the ignition circuit terminal 87 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 ignition circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the device.

• If the device activates

9. Test or replace the KR75 engine controls ignition relay.

Diagnostic D

1. Ignition OFF and all vehicle systems OFF, disconnect the KR76 retained accessory power relay. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 10 ohms between the ground circuit terminal 85 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 connection.

• If less than 10 ohms

3. Ignition ON.

4. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.

• If the test lamp does not illuminate and the circuit fuse is OK

1. Ignition OFF.

2. Test for less than 2 ohms in the ignition circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, verify the fuse is OK and there is voltage at the fuse.

• If the test lamp does not illuminate and the circuit fuse is open

1. Ignition OFF. repair the short to ground on the circuit

2. Test for infinite resistance between the ignition circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the KR76 retained accessory power relay.

• If the test lamp illuminates

5. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.

6. Verify the test lamp turns ON and OFF when commanding the accessory/retained accessory power relay ON and OFF with a scan tool.

• If the test lamp is always OFF

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 the test lamp is always ON

1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.

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 the test lamp turns ON and OFF

7. Verify that a test lamp does not illuminate between the ignition circuit terminal 87 and ground.

• If the test lamp illuminates

Repair the short to voltage on the ignition circuit

• If the test lamp does not illuminate

8. Ignition ON, connect a 3 A fused jumper wire between the B+ circuit terminal 30 and the ignition circuit terminal 87.

9. Verify device is activated.

• If the device does not activate

1. Ignition OFF, disconnect the harness connector at the device.

2. Test for infinite resistance between the ignition 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 ignition circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the device.

• If the device activates

10. Test or replace the KR76 retained accessory power relay.

Component Testing

Relay Test

1. Ignition OFF, disconnect the appropriate relay.

2. Test for 70-150 ohms between terminals 85 and 86.

• If less than 70 or greater than 150 ohms

Replace the relay.

• If between 70-150 ohms

3. Test for infinite resistance between the terminals listed below:

* 30 and 86

* 30 and 87

* 30 and 85

* 85 and 87

• If less than infinite resistance

Replace the relay.

• If infinite resistance

4. Test for less than 5.0 ohms between terminals 30 and 87.

• If 5.0 ohms or greater

Replace the relay.

• If less than 5.0 ohms

5. Install a 3 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground.

6. Test for less than 5.0 ohms between terminals 30 and 87.

• If 5.0 ohms or greater

Replace the relay.

• If less than 5.0 ohms

7. All OK

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)

* Control Module References Control Module References for the appropriate module replacement, programming and setup