P1A56

DTC P1A56

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.

DTC Descriptor

DTC P1A56

-
Hybrid/EV System Voltage Discharge Circuit

Circuit/System Description

The generator control module also called the starter generator control module is comprised of the following three control modules; the hybrid powertrain control module, 14 volt power module and the drive motor control module. These three control modules are non serviceable and are part of the generator control module.

The generator control module contains DC high voltage capacitors and a resistor circuit intended to discharge the electrical energy stored within those capacitors. Whenever the high voltage contactors are opened, the hybrid powertrain control module connects the internal resistor circuit across the capacitor circuit. The level of the high voltage is monitored by the hybrid powertrain control module before and after the resistor circuit has been connected. If the voltage level remains high for too long, the hybrid powertrain control module sets this DTC and then commands the motor control module to connect the drive motor generator 3 phase circuits across the DC high voltage positive and negative circuits thereby discharging the capacitors.

Conditions for Running the DTC

High Voltage Contactors are commanded Open.

Conditions for Setting the DTC

Within 300 milliseconds after commanding contactors open, the high voltage bus voltage fails to decrease by at least 18 V.

Or

Within 300 milliseconds after commanding contactors open, the high voltage bus voltage is greater than 60 V.

Or

The active bus discharge circuit status is disabled.

Action Taken When the DTC Sets

* DTC P1A56 is a Type B DTC.

* The drive motor control module is commanded to discharge the capacitor through the drive motor generator 3 phase stator circuits.

Conditions for Clearing the DTC

DTC P1A56 is a Type B DTC.

Diagnostic Aids

A high-pitched whine may emanate from the drive motor whenever the HV DC capacitance is discharged through the drive motor stator circuits.

Reference Information

Schematic Reference

Hybrid Energy Storage Schematics [1][2]Electrical Diagrams

Description and Operation

* Starter Generator Description and Operation Starter Generator Description and Operation

* Generator Control Module Description and Operation Generator Control Module Description and Operation

* Hybrid Modes of Operation Description Hybrid Modes of Operation Description

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Circuit/System Verification

1. Verify other DTCs are not set.

• If other DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

2. If the DTC is set, program the K59 starter generator control module. If the DTC resets, replace the K59 starter generator control module.

Repair Instructions

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

Control Module References Programming and Relearning for Generator Control Module, also called Starter Generator Control Module, replacement, programming and setup.