P1AB1

DTC P1AB1

Diagnostic Instructions

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



DTC Descriptor
DTC P1AB1
- Starter/Generator Phase U-V-W Current Sensor Overcurrent




Circuit/System Description

The starter/generator control module (SGCM) monitors the phase U/V/W current sensor to detect 3 phase overcurrent and to protect the MOSFET.


Conditions for Running the DTC

* Engine is running.
* Wake up signal is ON.



Conditions for Setting the DTC

Over current signal set for 20 ms.


Action Taken When the DTC Sets

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



Conditions for Clearing the DTC

Over current signal not valid


Diagnostic Aids

* Possible MGU winding short to other winding or short to case
* Possible FET breakdown or gate driver circuit fault



Reference Information
Schematic Reference

Hybrid Controls Schematics ()
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for Scan Tool Information


Circuit/System Testing

Caution: To help avoid personal injury, additional precautions must be taken prior to working on the generator control module or the generator starter. After removing the 36V battery cables from the generator battery, remove both engine wiring harness connectors from the generator control module. Wait at least 5 minutes and then remove the generator control module cover. Verify voltage levels at all 36V, 12V, and 3-phase connections, are less than 3 volts using a DMM before proceeding.


1. Disconnect the 3-phase cables from the SGCM. Refer to Generator Control Module 3-Phase Cable Assembly Replacement ().
2. Test each of the 3-phase cables individually for a short to ground.

• If any circuit indicates a short to ground, disconnect the 3-phase cables from the MGU.
• If the short to ground condition is longer present, replace the MGU.

3. Test each of the 3-phase cables individually for a short to ground.

• If any circuit does not test normal, replace the 3-phase cable assembly.

4. If all circuits test normal, replace the SGCM.



Repair Instructions

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

* Generator Control Module 3-Phase Cable Assembly Replacement ()
* Generator with Starter Replacement ()
* Control Module References (Programming and Relearning) for SGCM replacement, setup, and programming