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High Voltage System Inspection




High Voltage System Inspection

Vehicle Collision Detection

This vehicle contains a high voltage circuit impact detection (HVCID) sensor in addition to the supplemental inflatable restraint (SIR) impact sensors. The SIR sensors are designed to identify the severity of a collision and from what direction a collision has occurred. The SIR sensors typically detect collision conditions for occupant impact-protection reasons. The HVCID sensor is located in the front of the vehicle and is designed to detect an offset collision that may have damaged the high voltage system. The drive motor generator control module, also called the hybrid powertrain control module (HPCM), will open the high voltage contactor relays and disable the vehicle whenever an SIR deployment occurs or the HVCID sensor detects a collision event. The HVCID sensor detection of a vehicle impact does not cause SIR deployment.

The serial data gateway module (SDGM) monitors the HVCID sensor for collision/impact detection and operational status. The SDGM transmits a GMLAN message to the HPCM whenever an HVCID impact event or sensor fault is detected.

A complete inspection of the high voltage (HV) system and components must be performed if the vehicle has been involved in a collision. The HVCID sensor and/or SIR Deployed vehicle-disable condition will remain active until cleared by the HPCM output control function of the scan tool.

Inspection Procedure

Danger: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.


The High Voltage Disabling procedure will perform the following tasks:


* Identify how to disable high voltage.

* Identify how to test for the presence of high voltage.

* Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.


Failure to follow the procedures exactly as written may result in serious injury or death.


1. Perform the high voltage disable procedure at the drive motor generator battery cable connections. Refer to High Voltage Disabling High Voltage Disabling.

• If vehicle damage does not allow access to the high voltage manual disconnect, disconnect the 12V battery and remove the damaged portion of the vehicle until such time as the HV manual disconnect can be removed and the High Voltage Disabling High Voltage Disabling procedure can be completed.

2. Perform a visual inspection of the HV DC 300V cables between the drive motor generator power inverter module (PIM) and the drive motor generator battery assembly. Inspect for pinched, cut or frayed cables.

• Record any observed damage and continue.

3. Perform a visual inspection of the HV DC 300V cables between the PIM and the air conditioning compressor. Inspect for pinched, cut or frayed cables.

• Record any observed damage and continue.

4. Perform a visual inspection of the 3 phase cables between the PIM and the transmission case. Inspect for pinched, cut or frayed cables. Inspect the conduit for kinks or dents.

• Record any observed damage and continue.

5. Perform a visual inspection of the 42V power steering cables between the accessory DC power control module (APM) and the power steering control module (PSCM). Inspect for pinched, cut or frayed cables.

• Record any observed damage and continue.

6. Perform a visual inspection of the drive motor generator control module assembly. Inspect the assembly for cracks, dents or other physical damage.

• Record any observed damage and continue.

7. Perform a visual inspection of the air conditioning compressor assembly. Inspect the assembly for cracks, dents or other physical damage.

• Record any observed damage and continue.

8. Perform a visual inspection of the transmission assembly. Inspect the assembly for cracks, dents or other physical damage.

• Record any observed damage and continue.

9. Perform a visual inspection of the drive motor generator battery assembly. Inspect the assembly for cracks, dents or other physical damage.

• Record any observed damage and continue.

10. Replace all components identified as damaged.

• With a scan tool clear the HVCID and/or SIR Deployed vehicle disable condition only after all high voltage components identified as damaged have been replaced.

HVCID and/or SIR Deployed Vehicle Disable Condition Clearing Procedure

1. Perform the Inspection Procedure if the vehicle has been involved in a collision.
2. Ignition ON, clear the SDGM vehicle disable condition with a scan tool.

• If the SDGM had a HVCID sensor fault DTC, repair the condition and clear SDGM DTC Information.
• If the SDGM had an HVCID collision detection condition, perform the SDGM Crash Sensor Reset special function.

3. Ignition OFF, wait 2 minutes.
4. Ignition ON, clear the HPCM vehicle disable condition with the scan tool HPCM Clear 300V Impact Detection Status special function.
5. Ignition OFF, wait 2 minutes.
6. Perform the HV Enable Procedure. Refer to High Voltage Enabling High Voltage Enabling.

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