With ATH

DTC B302A (with ATH)

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 B302A 00
- Telematic Requested Immobilization

Circuit/System Description

As part of the vehicle telematics enhanced services, a request may be sent to the remote control door lock receiver (RCDLR) to disable vehicle starting. If a valid message is received by the RCDLR requesting that starting be disabled, the start enable message will not be sent to the engine control module (ECM).

Conditions for Setting the DTC

A valid start disable from telematics will set DTC B302A only as a history DTC.

Action Taken When the DTC Sets

Vehicle starting will be suspended and the security indicator will be illuminated.

Conditions for Clearing the DTC

* A current DTC will clear when the telematic start disable request is no longer seen.
* A history DTC will clear after 100 ignition cycles in which the telematic start disable request is not seen.

Diagnostic Aids

DTC B302A is only an indicator that a start disable request has been received from the vehicle telematics system and does not indicate a fault in the immobilizer system. B302A will only set as a history DTC.

Reference Information
Schematic Reference

Immobilizer Schematics Immobilizer Schematics
Connector End View Reference

Component Connector End Views Connector Views
Description and Operation

Immobilizer Description and Operation (with ATH) Immobilizer Description and Operation (with ATH)Immobilizer Description and Operation (without ATH) Immobilizer Description and Operation (without ATH)
Electrical Information Reference

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Turn the ignition ON.
2. Observe the security indicator. After approximately 10 minutes, the indicator will turn off.
3. Turn the ignition OFF and wait 5 seconds.
4. Repeat steps 2-4 two more times for a total of 3 cycles or 30 minutes.
5. Turn the ignition ON. The start disable will now be cleared.
6. Using the Red Emergency Button, notify the OnStar advisor that the Ignition Block on the vehicle has been cleared and to update the account status.