Diagnostic Fault Information
Important: Always perform the Diagnostic System Check -
Vehicle. Refer to
Diagnostic System Check - Vehicle
, prior to using this diagnostic procedure.
Circuit/System Description
The instrument cluster controls the operation of the ABS indicator. The electronic
brake control module (EBCM) reports the desired status of the ABS indicator via serial
data messages. The ABS indicator signal circuit is a back-up reporting circuit to
the serial data messages. The EBCM supplies ground through the circuit when the ABS
is operating correctly. When there is a concern with ABS that should turn on the ABS
indicator, the EBCM opens the ABS indicator signal circuit. If there is a concern
with the ABS serial data messages, the instrument cluster uses the ABS indicator signal
to determine if the ABS indicator should be illuminated. Using the serial data messages
and back-up circuit, the instrument cluster decides whether to turn on the ABS indicator.
Reference Information
Schematic Reference
Antilock Brake System Schematics
.
Connector End View Reference
Component Connector End Views
.
Electrical Information Reference
Scan Tool Reference
Control Module References
.
Circuit/System Testing
- Verify the electronic brake control module (EBCM) ground is clean and
torqued to the correct specification.
⇒ | If the EBCM ground is not clean and not torqued to the correct specification
clean and retension the EBCM ground terminal. |
- Install a scan tool.
- Ignition ON, engine OFF, observe the ABS Failed parameter in the Body/EBCM/data
list.
⇒ | If the indicator parameter does not display OFF inspect for poor connections
at the harness connector of the EBCM. |
⇒ | If the connections at the harness connector of the EBCM are OK, replace the
EBCM. |
- Ignition ON, engine OFF, observe the ABS indicator on the instrument panel
cluster (IPC) during the displays test.
⇒ | If the ABS indicator does not illuminate during the displays test and then turn
OFF inspect for poor connections at the harness connector of the IPC. |
⇒ | If the connections at the harness connector of the IPC are OK, replace the IPC. |
Repair Instructions