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.


Action Taken When the DTC Sets

Adaptive cruise control (ACC) is inoperative.


Conditions for Clearing the DTC

* The DTC becomes history when the fault is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.



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

Important: This DTC may be stored as a history DTC without affecting the operation of the DSCC or FLS. Do not replace the DSCC or FLS if this DTC is stored only as a history DTC and is not retrieved as a current DTC.



1. Ignition ON, verify that DTC B1020 is not current in the DSCC.

• If the DTC is stored as a current DTC, 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