P1A8C
DTC P1A8B or P1A8C
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 Instructionsprovides an overview of each diagnostic category.
DTC Descriptors
DTC P1A8B 00
- 42 Volt Inverter Temperature High
DTC P1A8B 11
- 42 Volt Inverter Temperature High
DTC P1A8C
- 42 Volt Inverter Overtemperature
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.
Heat is generated in the 42 volt accessory DC power control module primarily through the demand for use of the electronic power steering. The ECM measures the temperature of the power electronics cooling loop and commands the flow of 2 electrical coolant pumps. The accessory DC power control module transfers heat from the 42 volt circuit to the accessory DC power control module heat plate which is then dissipated at the Generator Control Module Coolant Radiator.
Based on the severity of the over temperature condition in the 42 volt circuit, the accessory DC power control module will take actions ranging from notifying the electronic power steering control module of an over temperature condition to completely shutting down 42 volt power conversion.
Conditions for Running the DTC
Accessory DC power control module 42 volt output commanded on.
Conditions for Setting the DTC
P1A8B 00
42 volt circuit temperature is greater than 105°C (221°F).
P1A8B 11
42 volt circuit temperature is greater than 115°C (239°F).
P1A8C
42 volt circuit temperature is greater than 125°C (257°F).
Action Taken When the DTC Sets
P1A8B
* DTC P1A8B is a Type C DTC.
* The hybrid powertrain control module stores the DTC information in memory when the diagnostic runs and fails.
P1A8C
* DTC P1A8C is a Type C DTCs.
* The hybrid powertrain control module stores the DTC information in memory when the diagnostic runs and fails.
* The accessory DC power control module will shut down 42-volt conversion.
Conditions for Clearing the DTC
P18AB
DTC P1A8B is a Type C DTC.
P1A8B 00
DTC P1A8B 00 is a Type C DTC.
P1A8B 11
DTC P1A8B 11 is a Type C DTC.
P1A8C
DTC P1A8C is a Type C DTC.
Diagnostic Aids
This DTC could be caused by a possible power electronics cooling system failure due to the following:
* Restricted radiator air flow or coolant fans inoperative
* Restricted power electronics coolant flow or contaminated coolant
* Inoperative power electronics cooling system water pump
Reference Information
Schematic Reference
Hybrid Controls Schematics Hybrid Controls Schematics
Connector End View Reference
Component Connector End Views Connector End Views By Name
Description and Operation
Drive Motor Generator Control Module Description and Operation Drive Motor Generator Control Module
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 Programming and Relearningfor scan tool information
Circuit/System Verification
1. Verify that DTC P0AF7 is not set.
• If the DTC is set, refer to DTC P0AF7 P0AF7.
2. Engine running, place the steering wheel in the centered position. Do not rotate the steering wheel. Verify the accessory DC power control module scan tool 42V Circuit Current parameter is less than 0.5 A.
• If greater than the specified value, replace the K43 power steering control module.
3. Observe the 42V Circuit Current parameter while rapidly rotating the steering wheel to the full left stop then to the full right stop. The highest current reading should be below 40 A.
• If the current is greater than the specified value, replace the K43 power steering control module.
• If the reading is less than the specified value, replace the K1 accessory DC power control module.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
Control Module References Programming and Relearningfor Accessory DC Power Control Module or Power Steering Control Module replacement, programming, and setup