Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC B1020 3C: Auxiliary Electronic Control Unit (ECU) Performance Internal Communications FailureCircuit/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
Connector End View Reference
Description and Operation
Cruise Control Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Verify that DTC B1020 is not set.
- If the DTC is stored only as a history DTC, refer to Diagnostic Aids. Do not replace the DSCC or FLS.
| ⇒ | If the DTC is set, replace the FLS. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for DSCC or FLS replacement, setup, and programming
