Service Information

Volt

DTC P1E27 or P1E28

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 P1E27: Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery System Voltage High Voltage

DTC P1E28: Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery System Voltage

Circuit/System Description

The power inverter module, often referred to as the drive motor generator power inverter module, contains three motor control modules and the hybrid powertrain control module. Two of the motor control modules operate their respective drive motor generator based upon power inverter module commands. The third motor control module controls the auxiliary transmission fluid pump motor. Each drive motor control module monitors its internal high voltage sensor for correct operation, no external circuits are involved. The motor control modules and the hybrid powertrain control module are part of the power inverter module and are not serviced separately.

Conditions for Running the DTC

•	The vehicle is ON.

•	High-voltage contactors are closed.

P1E28

DTC P1E20 or P1E21 is not set.

Conditions for Setting the DTC

DTC P1E27

The motor control module detects High Voltage greater than 425 V.

DTC P1E28

The motor control module detects a correlation fault while comparing the mid-pack and overall pack voltage.

Action Taken When the DTC Sets

•	DTC P1E27 is a Type A DTC.

•	DTC P1E28 is a Type B DTC.

Conditions for Clearing the DTC

•	DTC P1E27 is a Type A DTC.

•	DTC P1E28 is a Type B DTC.

Diagnostic Aids

This DTC may set due to low 12 V system voltage.

Reference Information

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Circuit/System Verification

Verify that DTC P0562 is not set.

⇒	If DTC is set, refer to DTC B1325, B1330, B1517, C0800, C0899, C0900, C12E1, C12E2, P0562, P0563, P1A0C, P1A0D, or P1EFC .

If the DTC is set, program the T6 power inverter module. If the DTC resets, replace the T6 power inverter module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module, also called the power inverter module, replacement, programming and set-up.