GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2008 🢒 AURA 🢒 DTC 🢒 DTC P1AAE or P1AAF

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P1AAE: Starter/Generator Phase U-V-W Correlation

DTC P1AAF: Starter/Generator Phase U-V-W Circuit

Circuit/System Description

The starter/generator control module (SGCM) phase U/V/W current sensor is used for motor control and power inverter module (PIM) current sensor rationality check. The current sensor is soldered on the control board near the phase U/V/W bus bar. The SGCM monitors the current sensor for the following:

P1AAE

To detect the electrical failure (short condition) of the phase current sensor

P1AAF

To detect a phase wire open condition

If one of the above conditions is detected, the SGCM will set the appropriate DTC.

Conditions for Running the DTC
    • The engine is running.
    • Main relay is closed.

Conditions for Setting the DTC

P1AAE

Current is less than or greater than 200A for 20 ms.

P1AAF

Current output is greater than 200A for 200 ms.

Action Taken When the DTC Sets

P1AAE

    • Stop pulse width modulation (PWM) (motor generator unit (MGU) shutdown)
    • Auxiliary power module (APM) PWM OFF
    • Battery disconnection (disconnect SW on/off)

P1AAF

Stop PWM (MGU shutdown)

Conditions for Clearing the DTC

P1AAE

Sum of 3 phase current returns to normal.

P1AAF

Current amp output returns to normal.

Diagnostic Aids

P1AAE

    • Possible short circuit
    • Possible internal failure at current sensor

P1AAF

    • Possible 3- phase cable open
    • Possible MGU winding open.

Reference Information

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Starter/Generator Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing
  1. Ignition OFF, disable the hybrid system. Refer to Hybrid Battery Service Disconnect/Connect.

    2. Notice: Refer to Fastener Tightening Specifications in the Preface section.

    Important: It is important that the 3-phase cable connections are clean and the fasteners are torqued to specifications.

  2. Inspect for poor connections and any evidence of arching at the 3-phase cable connectors of the SGCM and the MGU.
  3. Disconnect the 3-phase cables from the SGCM. Refer to Generator Control Module 3-Phase Cable Assembly Replacement
  4. Test for infinite between each of the 3-phase cables.
    5. • Cable U to V
    • Cable U to W
    • Cable V to W
  5. Test for infinite resistance between each of the 3-phase cables and ground.
    6. ⇒If the circuits test normal, replace the SGCM.
  6. Disconnect the 3-phase cables from the MGU. Refer to Generator Control Module 3-Phase Cable Assembly Replacement.
  7. Test for less than 1 ohm on each of the 3-phase cables.
    8. ⇒If the circuits test normal, replace the MGU.
    ⇒If not within the specified value , replace the 3-phase cable assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Generator Control Module 3-Phase Cable Assembly Replacement
    •  Generator with Starter Replacement
    •  Control Module References for SGCM replacement, setup, and programming