GM Service Manual Online
For 1990-2009 cars only

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 P1553: Adaptive Cruise Control Signal Circuit

Circuit/System Description

The forward looking sensor (FLS) radar is a part of the distance sensing cruise control (DSCC) module but has the exclusive function of detecting, tracking and classifying targets within its specified field of view. The FLS radars ability to detect and react to objects of interest in its detection zone is critical to the proper operation of the adaptive cruise control (ACC) system.

Conditions for Running the DTC

    • The ignition is ON.
    • The cruise switch is ON.

Conditions for Setting the DTC

    • The DSCC module detects there is 3.9 degrees of skew or error of the FLS.
    • The vehicle speed is at or greater than 40.2 km/h (25 mph).

Action Taken When the DTC Sets

    • Loss of adaptive cruise control (ACC) function.
    • Service Radar Cruise message is displayed in the driver information center (DIC).

Conditions for Clearing the DTC

    • The DTC becomes history when the conditions for setting the DTC are no longer present.
    • The history DTC clears after 100 malfunction-free ignition cycles.

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 vehicle or the DSCC module.

Reference Information

Schematic Reference

Cruise Control Schematics

Connector End View Reference

Cruise Control Connector End Views

Description and Operation

Cruise Control Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Special Tools

BO-47670 Adaptive Cruise Control (ACC) Radar Alignment Tool

Circuit/System Verification

  1. Align the FLS radar using the alignment tool. Refer to Distance Sensing Cruise Control Aiming .
  2. If alignment cannot be achieved within the limits of the available adjustment, inspect the mounting structures and brackets for damage or tampering and repair as necessary to achieve proper alignment.
  3. Road test the vehicle and ensure the ACC system functions normally and DTC C1002 does not set as current.
  4. If the DTC sets as current, replace the DSCC module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for DSCC module replacement, setup, and programming