P1AAE

DTC P1AAE or P1AAF

DTC Descriptor

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

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

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

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 200 Amps for 20 ms.

P1AAF

Current output is greater than 200 A 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 phase cable open.
* Possible MGU winding open.

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. If DTC is history, refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. Component Tests and General Diagnostics
2. Ignition OFF, disable the hybrid system. Refer to Hybrid Battery Service Disconnect/Connect.

Notice: Refer to Fastener Tightening Specifications.

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

3. Inspect for poor connections and any evidence of arching at the 3-phase cable connectors of the SGCM and the MGU.
4. Disconnect the 3-phase cables from the SGCM.
5. Test each of the 3-phase cables for an open as follows:

* Cable U to V
* Cable U to W
* Cable V to W

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

• If all circuits test normal, replace the SGCM.

7. Disconnect the 3-phase cables from the MGU.
8. Test each of the 3-phase cables individually for an open.

• If all circuits test normal, replace the MGU.

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

Repair Instructions

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

Control Module References for SGCM replacement, setup, and programming.

Generator Control Module 3-Phase Cable Assembly Replacement.

Generator with Starter Replacement.