P1A8A

DTC P1A8A

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 P1A8A
- 42 Volt System Voltage High

Circuit/System Description

The accessory DC power control module supplies the energy that flows between the high voltage, 300 volt, direct current (DC) and intermediate voltage, 42 volt, DC to support the electric power steering. The accessory DC power control module receives a 42 volt enable command from the hybrid powertrain control module over serial data. 42 volt accessory DC power control module functions will run only when the 42 volt accessory DC power control module enable is active on serial data.

Conditions for Running the DTC

Accessory DC power control module 42 volt output commanded on.

Conditions for Setting the DTC

Accessory DC power control module 42 volt circuit is more than 50 V for more than 3 seconds.

Action Taken When the DTC Sets

* DTC P1A8A is a Type C DTC.
* The Accessory DC power control module will shutdown the 42 volt conversion.

Conditions for Clearing the DTC

* DTC P1A8A is a Type C DTC.
* 42 volt circuit is below 48 V.

Diagnostic Aids

The accessory DC power control module Data List on the scan tool contains the parameter 42V Circuit Maximum. If this parameter has a voltage that is greater than 50 V, and the accessory DC power control module is functioning normally, the protection circuits in the power steering control module have failed allowing induced voltage to be present on the 42 V circuit.

Reference Information
Schematic Reference

Hybrid Controls Schematics Hybrid Controls Schematics
Connector End View Reference

Component Connector End Views Connector Views
Description and Operation

Drive Motor Generator Control Module Description and Operation Drive Motor Generator Control Module Description and Operation
Electrical Information Reference

* Circuit Testing Circuit Testing
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

Engine running, observe the 42V Circuit Voltage parameter on the accessory DC power control module data list.

If the 42V Circuit Voltage parameter is greater than 48 volts, replace the K1 accessory DC power control module.
If the 42V Circuit Voltage parameter is less than 48 volts, replace the K43 power steering control module.

Repair Instructions

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

Control Module References Control Module References for Accessory DC Power Control Module or Power Steering Control Module replacement, programming, and setup