P1A8F

DTC P1A8F

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 P1A8F
- 14 Volt Power Module Current Sensor Overcurrent

Circuit/System Description

The starter/generator control module (SGCM) monitors the 14-volt power module current sensor for an overcurrent condition to protect the MOSFET. In the hardware an overcurrent protection circuit is used to limit the current, and software monitors for an overcurrent reading in the sensor.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The 12 volt charge is greater than 150 amps or less than -150 amps for 2 seconds

Action Taken When the DTC Sets

* In the software fault:

- Stop PWM (MGU shutdown)
- APM PWM off

* In the hardware fault:

- Stop PWM (MGU shutdown)
- APM PWM off
- Battery disconnection (disconnect SW on/off)

Hybrid system is disabled.

Conditions for Clearing the DTC

* In the software fault, APM current less than +/- 10 amps
* 12VOUT is greater than 7 volts.
* APMTEMP is less than 105°C (221°F) for 160 ms.
* Clears 30 seconds after cycle wake up signal.

Diagnostic Aids

* Battery cable short to ground
* Fuse/relay box electrical failures
* FET breakdown

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

Starter/Generator Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

1. Inspect for any open fuses.
2. Inspect all the 12-volt battery connections for short to ground as follows:

* At battery
* At SGCM
* At fuse block

3. With a scan tool, clear the DTC.
4. Ignition OFF, wait 30 seconds.
5. Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset.

• If the DTC resets, replace the SGCM.

Repair Instructions

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

Control Module References (Programming and Relearning) for SGCM replacement, setup, and programming