Antilock Braking System (ABS)

DTC 13 ABS Warning Light Circuit Shorted To Battery:

ABS Warning Light:

CIRCUIT DESCRIPTION
This test checks the state of the Antilock Braking System (ABS) indicator lamp to identify a situation in which the driver could not be warned of a system malfunction by the ABS indicator lamp. The Lamp Driver Module (LDM) turns the ABS indicator lamp "ON" unless the Electronic Brake Control Module (EBCM) provides ground to turn it "OFF." Because of the circuitry internal to the LDM, only external malfunctions can be detected. As a result the ABS indicator lamp itself is not diagnosable, only the control line to the EBCM can be diagnosed.

If the ABS indicator lamp control line is shorted to battery or the EBCM control circuit is open, the EBCM is not able to turn "OFF" the ABS indicator lamp.

FAILURE CONDITION
DTC AO13 can be set anytime the EBCM commands the ABS indicator lamp "OFF." If the EBCM can not control the ABS indicator lamp for two seconds, a malfunction exists.

ACTION TAKEN
A malfunction DTC is stored however, ABS is not disabled.

TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks to see if ABS lamp functions properly. Normal operation would indicate that the problem is not present.
2. After removing the 10 amp gauge fuse, voltage on CKT 852 will be eliminated. If voltage is still present, it would indicate that a short to voltage is present between the lamp driver module and EBCM.

DIAGNOSTIC AIDS
An "Intermittent" malfunction may be caused by a poor connection, rubbed through wire insulation or a wire that is broken inside the insulation.

DTC 13 must be currently set before it should be addressed. If DTC 13 is set as a history DTC, proceed to those DTCs that are currently set before attempting to repair a DTC 13 malfunction.

The frequency of the malfunction can be checked by using the enhanced diagnostic function of the Tech 1.

Any circuitry that is suspected as causing the "Intermittent" complaint should be thoroughly checked for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections or physical damage to the wiring harness.