P1ABD

DTC P1ABD

Diagnostic Instructions

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

DTC Descriptor

DTC P1ABD
- 14 Volt Power Module Hybrid Battery System Voltage High

Circuit/System Description

The Accessory Power Module (APM) continuously monitors the High Voltage (300 volt) circuit during charge or Jump Assist. This DTC sets when the 300 volt circuit at the APM falls below a set level. APM functions will run only when an APM enable message from the Hybrid Powertrain Control Module (HPCM) is active on the high speed hybrid GMLAN communication circuit.

Conditions for Running the DTC

Accessory/Ignition On.

Conditions for Setting the DTC

* 300 volt circuit above 390 volts in Normal Mode more than 0.012 seconds.
* 300 volt circuit above 358 V in Jump-Assist Mode more than 0.012 seconds.

Action Taken When the DTC Sets

* The HPCM stores the DTC information in memory when the diagnostic runs and fails.
* The APM will shutdown conversion of both 42 volts and 14 volts.

Conditions for Clearing the DTC

* 300 volt circuit falls below 385 volts in Normal Mode for more than 0.012 seconds.
* 300 volt circuit falls below 353 volts in Jump-Assist Mode for more than 0.012 seconds.

Diagnostic Aids

When in Normal Mode operation, as the APM converts energy, it is merely monitoring the 300 volt DC bus. It has no direct control over the voltage on the bus becoming high. Therefore, other controllers should be interrogated to determine if they also set a DTC for over voltage. If so, the problem is not related to the APM.

In Jump-Assist Mode, the APM is in control of applying the voltage to the Bus. The HPCM should control the APM to prevent it from charging too high.

Circuit/System Verification

Clear the DTCs, cycle the ignition to OFF and back ON and then retest for DTCs.

Circuit/System Testing

1. Turn the ignition to ON. Insure the High Voltage Contactor Relays are closed.
2. Observe the scan tool HPCM 300 V Circuit Voltage Signal parameter in the APM data list. The value should be less than the specified value listed above.

^ If the value is less than the specified value, replace the APM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests