Grand AM L4-138 2.3L DOHC VIN D MFI (1994)
DTC 87 Red Brake Warning Lamp Circuit Open
CIRCUIT DESCRIPTION
This DTC is used to verify the Electronic Brake Control Module (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 Antilock Braking System (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.
FAILURE CONDITION
DTC A087 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. ABS is not disabled; however, the ABS indicator lamp will flash to indicate a malfunction exists.
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 warning lamp and illuminate it.
3. The brake warning lamp has current supplied to it through the 10 amp gauge fuse; therefore, this step would indicate if the ignition circuit is
complete to the I/P cluster.
4. This step isolates if the open circuit is due to a EBCM malfunction or open circuitry to the brake warning lamp.
5. This step test for high resistance in park brake circuitry.
6. This step identifies if high resistance is present in the fluid level switch circuitry.
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.
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.
88 Red Brake Warning Lamp Circuit Shorted to Battery
