A087

Fig. 511 Code 87: Red Brake Warning Lamp Circuit Shorted Open (Part 1 Of 2):

Fig. 511 Code 87: Red Brake Warning Lamp Circuit Shorted Open (Part 2 Of 2):

DTC A087 Red Brake Warning Lamp Circuit Shorted Open:

Circuit Description:
This DTC is used to verify the EBCM has continuity to the "BRAKE" indicator in case the EBCM must turn it on. This will only occur if an ABS malfunction is detected that may degrade base brake operation. Because ABS is not the only device controlling the "BRAKE" indicator (parking brake switch and brake fluid level switch may also turn it on), a short to ground in this circuit cannot be detected.

Failure Condition:
DTC AO87 can be set after vehicle speed exceeds 8 km/h (5 mph). If the "BRAKE" indicator circuit voltage is out of specification (indicating an open circuit), a malfunction exists.

Action Taken:
A DTC AO87 is stored. ABS is not disabled and the "ABS" indicator will not be illuminated.

Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This step identifies if the malfunction is currently present.
2. This step indicates if the EBCM and circuitry has the ability to complete the ground to the "BRAKE" indicator and illuminate it.
3. This step checks for an open in the parking brake circuitry.
4. This step determines whether or not the condition is intermittent.
5. Because the "BRAKE" indicator has current supplied to it through the GAUGE fuse, this step would indicate if the ignition circuit is complete to the I/P cluster.
6. This step determines whether the open circuit is due to an EBCM failure or an open wire in the "BRAKE" indicator.

Diagnostic Aids:
An "intermittent" malfunction may be caused by a loose connection, rubbed through wire insulation or a wire that is broken inside the insulation.

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

Any circuitry that is suspected of 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.