Deceleration Sensor
NOTE:
During deceleration sensor diagnosis, ABS functions like a standard brake system.
- Ensure battery voltage is about 12 volts. Turn ignition on. ABS light should come on, then go out after 3 seconds. If ABS light does not come on, check fuse, bulb, and wiring harness.
- Turn ignition off. DO NOT remove short pin from DLC1. Connect jumper wire between DLC1 terminals E1 and Ts. See Figure. Engage parking brake. Press and hold brake pedal. Start engine.
- ABS light should flash 4 times per second. If ABS light flashes, go to next step. If ABS light does not flash, go to ABS WARNING LIGHT CIRCUIT under CIRCUIT TESTS. A deceleration sensor malfunction will cause ABS light to flash Code 79.
- To inspect sensor detection point, slowly raise rear of vehicle and measure height from center of lower body of vehicle to ground. See Fig 1. Verify ABS light is off. If light is on, inspect deceleration sensor installation. Repair if necessary. If deceleration sensor installation is okay, replace sensor.
- Slowly lower rear of vehicle. Slowly raise front of vehicle and measure height from center of lower body of vehicle to ground. Verify ABS light is off. If ABS light is on, inspect deceleration sensor installation. Repair if necessary. If deceleration sensor installation is okay, replace sensor.
- Slowly lower vehicle. To inspect sensor operation, drive vehicle straight ahead at about 12 MPH or more. Press brake pedal lightly. ABS light should flash 4 times per second with no change in pattern.
- Drive vehicle straight ahead at about 12 MPH or more. Using moderate force, press brake pedal. ABS light should stay on during braking and return to normal pattern when released. Drive vehicle straight ahead at about 12 MPH or more. Press brake pedal firmly, then release it. ABS light should be on during braking, then flash 4 times per second, then stay on until after brake pedal is released when it returns to normal pattern.
- If ABS light does not function as described, check deceleration sensor installation. If sensor installation is okay, replace deceleration sensor. Turn engine off. Remove jumper wire from DLC1.