B1020

DTC B1020

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 B1020 3C
- Auxiliary Electronic Control Unit (ECU) Performance Internal Communications Failure

Circuit/System Description

The distance sensing cruise control module (DSCC) communicates with the radar forward looking sensor (FLS) via controller area network (CAN) serial data. When there is an internal fault in the FLS, this DTC will set in the DSCC.

Conditions for Running the DTC

The DSCC runs the program to detect a fault when power up is commanded.

Conditions for Setting the DTC

The module has detected a fault with the FLS while cruise is engaged or attempted to be engaged.

Actions Taken When the DTC Sets

* The malfunction indicator lamp (MIL) will not illuminate.
* The adaptive cruise control (ACC) is disabled.
* The cruise control system is disabled.
* Service Radar Cruise message is displayed in the driver information center (DIC).

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear after 40 malfunction-free ignition cycles have occurred.

Diagnostic Aids

An FLS radar out of alignment condition may be as a result of tampering with the DSCC module mounting structures/brackets or the adjuster settings. An out of alignment condition may also be a result of damage to the front section of the ACC equipped vehicle or the DSCC module.

Reference Information
Schematic Reference

Cruise Control Schematics (Conventional) (Cruise Control Schematics (Conventional))Cruise Control Schematics (Adaptive) (Cruise Control Schematics (Adaptive))
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Cruise Control Description and Operation (Adaptive Cruise) (Cruise Control Description and Operation (Adaptive Cruise))Cruise Control Description and Operation (Conventional Cruise) (Cruise Control Description and Operation (Conventional Cruise))
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 Testing

1. Verify that DTC B1020 is not set.

• If the DTC is set, replace the FLS.

2. If the DTC is stored only as a history DTC, refer to Diagnostic Aids. Do not replace the DSCC or FLS.

Repair Instructions

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

Control Module References (Programming and Relearning) for DSCC or FLS replacement, setup, and programming