P0AA1

DTC P0AA1

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 P0AA1
- Hybrid Battery Positive Contactor Circuit Stuck Closed




Circuit/System Description

The battery energy control module (BECM) monitors to detect a fault with the contactor.


Conditions for Running the DTC

Ignition to OFF, transition from contactor closed to contactor open.


Conditions for Setting the DTC

Absolute Value (Pack Voltage - Link Voltage) is less than 1 volt.


Action Taken When the DTC Sets

The hybrid system is disabled.


Conditions for Clearing the DTC

* State = Run or Service or Powerdown.
* Pack current is less than -0.1 amps.
* Contactor state = Open.
* Contactor status = Open Service Disconnect.
* Current sensor DTCs = Passed.
* Pack voltage reading = Valid.
* Pack voltage DTCs = Passed.



Reference Information
Schematic Reference

Hybrid Energy Storage 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 Verification

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.


Caution: To help avoid personal injury, be careful when working in the vicinity of the generator battery disconnect control module. Internal components will still be live, 36V potential, even when the cover has been opened or removed.


1. If there are any current DTCs set, diagnose those first, including any clearing any codes.
2. Cycle the ignition switch from OFF to RUN several times, allowing at least 5 seconds after each transition from Ignition OFF to RUN.

• If the DTC resets, replace the BECM.




Repair Instructions

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


Control Module References (Programming and Relearning) for BECM replacement, setup, and programming.