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DTC B0978, B097B, or B097C

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0978 01: Power Mode Accessory Indicator Control Circuit Short to Battery

DTC B0978 02: Power Mode Accessory Indicator Control Circuit Short to Ground

DTC B0978 04: Power Mode Accessory Indicator Control Circuit Open

DTC B097B 00: Power Mode Start Switch Circuit Malfunction

DTC B097B 02: Power Mode Start Switch Circuit Short to Ground

DTC B097B 04: Power Mode Start Switch Circuit Open

DTC B097B 08: Power Mode Start Switch Circuit Performance - Signal Invalid

DTC B097B 61: Power Mode Start Switch Circuit - Stuck

DTC B097C 01: Power Mode Run/Start Circuit Indicator Short to Battery

DTC B097C 02: Power Mode Run/Start Circuit Indicator Short to Ground

DTC B097C 04: Power Mode Run/Start Indicator Circuit Open

Circuit/System Description

The ignition mode switch has 2 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 (ACC) will illuminate. The accessory mode has a 5 minute timeout to reduce battery drain. Pressing the ignition mode switch button a second time (without the brake pedal applied), the vehicle enters the run/start mode (without the engine running) and the green LED (Run/Start) will illuminate. Pressing and holding the push button start switch for at least 5 seconds 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. 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 passive entry passive start module (PEPS) and to the BCM. The PEPS module sends a redundant signal to the BCM with the ignition mode switch status.

Conditions for Running the DTC

Voltage supplied to the module is in the normal operating voltage range of 9-16 V.

Conditions for Setting the DTC

B0978, B097C 01

    • The BCM detects a short to battery in the respective indicator control circuit, when the output is active.
    • The above condition exists for more than 1 second.

B0978, B097B, B097C 02

    • The BCM detects a short to ground in the respective circuit, when the output is inactive.
    • The above condition exists for more than 1 second.

B0978, B097B, B097C 04

    • The BCM detects an open in the respective circuit, when the output is inactive.
    • The above condition exists for more than 1 second.

B097B 00

    • The BCM detects a difference between the ignition mode switch voltages to the BCM and PEPS module.
    • The above condition exists for more than 1 second.

B097B 08

    • The BCM detects a difference between the ignition mode switch voltages to the BCM and PEPS module.
    • The above condition exists for more than 1 second.

B097B 61

    • The BCM and the PEPS module detect a continuously closed ignition mode switch.
    • The above condition exists for more than 1 minute.

Action Taken When the DTC Sets

The BCM disables the respective output until the next ignition cycle.

Conditions for Clearing the DTC
    • A current DTC clears when the malfunction is no longer present.
    • A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Reference Information

Schematic Reference

Power Moding Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Retained Accessory Power Description and Operation
    •  Power Mode Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Without the brake pedal applied, push the ignition mode switch button twice. Observe the operation of the ignition mode switch LED's. The amber LED should light after the first button push and the green LED should light after the second button push. The engine should not crank and the ignition mode should be run.

With the brake pedal applied, push the ignition mode switch once. Observe the operation of the ignition mode switch LED's. The green LED should light after one button push. The engine will crank.

Circuit/System Testing

B097B 61

Verify DTC B097B 61 is not set.

⇒If DTC B097B 61 is set in both the BCM and PEPS module, replace the S38 ignition mode switch.

B0978 01, B0978 02, B0978 04, B097B 00, B097B 02, B097B 04, B097B 08, B097C 01, B097C 02, B097C 04

  1. Ignition OFF, disconnect the harness connector at the S38 ignition mode switch.
  2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 15 Ω between the ignition mode switch terminal 4 and ground.
    3. ⇒If greater than specified range, test the circuit for an open/high resistance.
  3. Reconnect the harness connector at the S38 ignition mode switch.
  4. Ignition ON, disconnect the harness connector at the S38 ignition mode switch.
  5. Verify a test lamp illuminates between ignition mode switch terminal 6 and ground.
    6. ⇒If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal replace the K9 BCM.
  6. Connect a test lamp between the control circuit 5 and ground.
  7. Command the body control module-keyless entry control module-run/start power mode indicator test with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    8. ⇒If the test lamp is always ON, test the control circuit for a short to voltage. If all circuits test normal, replace the K9 BCM.
    ⇒If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If all circuits test normal, replace the K9 BCM.
  8. Connect a test lamp between the control circuit 2 and ground.
  9. Command the body control module-keyless entry control module-accessory power mode indicator test with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    10. ⇒If the test lamp is always ON, test the control circuit for a short to voltage. If all circuits test normal, replace the K9 BCM.
    ⇒If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If all circuits test normal, replace the K9 BCM.
  10. If all circuits test normal, replace the S38 ignition mode switch.

Component Testing
  1. Ignition OFF, disconnect the harness at the S38 ignition mode switch.
  2. Place a jumper wire between ignition mode switch terminal 4 and ground.
  3. Place a fused jumper wire between the circuit terminals of the ignition mode switch listed below and B+:
    4. • Ignition mode switch terminal 2
    • Ignition mode switch terminal 5
    ⇒If the either LED does not light, replace the S38 ignition mode switch.
  4. Without the button pressed, test for 4,870 Ω between the ignition mode switch terminals listed below:
    5. • Ignition mode switch terminals 3 and 7
    • Ignition mode switch terminals 4 and 6
    ⇒If not the specified value, replace the S38 ignition mode switch.
  5. With the button pressed, test for 1,300 Ω between the ignition mode switch terminals listed below:
    6. • Ignition mode switch terminals 3 and 7
    • Ignition mode switch terminals 4 and 6
    ⇒If not the specified value, replace the S38 ignition mode switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Ignition and Start Switch Replacement
    • Control Module References for BCM replacement, programming and setup
   


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