U1806

DTC U1806

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC U1806
- Battery Energy Control Module High Voltage Energy Management CAN Bus Off

For symptom byte information, refer to Symptom Byte List Symptom Byte List.

Circuit/System Description

The high voltage energy management high speed GMLAN serial data circuits are serial data buses used to communicate information between the Hybrid Powertrain Control Module 2, the Battery Energy Control Module, and the Battery Charger. If this serial data system is inoperative the devices will not communicate with each other on this bus, but they still communicate with the scan tool through high speed GMLAN bus.

The scan tool does not communicate with devices through the high voltage energy management high speed GMLAN bus. The high voltage energy high speed GMLAN serial data circuits connect directly to the auxiliary data connector and do not connect with the scan tool.

Conditions for Running the DTC

* Vehicle ON.

* The system voltage is at least 9 V.

Conditions for Setting the DTC

The device setting the DTC has attempted to establish communications on the serial data circuits for more than 1.4 seconds without success.

Action Taken When the DTC Sets

The DTC U1806 is a type B DTC.

Conditions for Clearing the DTC

The DTC U1806 is a type B DTC.

Circuit/System Verification

1. Vehicle in Service Mode.

2. Verify DTC U1806 is not set.

• If DTC U1806 is set
Refer to DTC U007A U007A.

• If DTC U1806 is not set

3. All OK