Antilock Braking System (ABS)
^�y DTC 87 Red "Brake" Warning Lamp Circuit Open:
DTC 87 Red "Brake" Warning Lamp Circuit Open:
Circuit Description:
This DTC is used to verify the EBCM has continuity to the "BRAKE" warning lamp 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" warning lamp (parking brake and low fluid sensor may also turn "ON" the lamp) a short to ground in this circuit can not necessarily be detected. Excessive resistance in the fluid level switch or parking brake circuitry may set this DTC.
DTC Will Set When:
DTC 87 can be set after initialization is completed. If the red "BRAKE" warning lamp circuit voltage is out of specification indicating an open circuit, a malfunction exists.
Action Taken:
A malfunction DTC is stored, however ABS is not disabled.
DTC Chart Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This step identifies if the red "BRAKE" warning lamp can be turned "ON."
2. This step test for high resistance in park brake circuitry.
3. Ensures malfunction was not due to poor terminal contact.
4. This step identifies if high resistance is present in the fluid level switch circuitry.
5. Checks integrity of red "BRAKE" warning bulb.
6. Checks for high resistance in the "BRAKE" warning lamp control circuit.
Diagnostic Aids:
An "Intermittent" malfunction is most likely caused by a poor 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.
If the Tech 1 is not available, the parking brake handle may be lifted to verify proper lamp operation and continuity of CKTs 3 and 39.
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.