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 CorrelationDTC 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
Connector End View Reference
Description and Operation
Starter/Generator Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disable the hybrid system. Refer to Hybrid Battery Service Disconnect/Connect.
- Inspect for poor connections and any evidence of arching at the 3-phase cable connectors of the SGCM and the MGU.
- Disconnect the 3-phase cables from the SGCM. Refer to Generator Control Module 3-Phase Cable Assembly Replacement
- Test for infinite between each of the 3-phase cables.
- Test for infinite resistance between each of the 3-phase cables and ground.
- Disconnect the 3-phase cables from the MGU. Refer to Generator Control Module 3-Phase Cable Assembly Replacement.
- Test for less than 1 ohm on each of the 3-phase cables.
Note: It is important that the 3-phase cable connections are clean and the fasteners are torqued to specifications. Refer to Fastener Tightening Specifications.
| • | Cable U to V |
| • | Cable U to W |
| • | Cable V to W |
| ⇒ | If the circuits test normal, replace the SGCM. |
| ⇒ | 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.
| • | Control Module References for SGCM replacement, setup, and programming |
