Test 5: Parking Brake Switch Circuit
WARNING: This page is about a different car, the 1997 Lexus SC 400. However, it is still accessible from the selected car via links, so may be relevant.
- Start engine. Apply parking brake. BRAKE warning light on instrument cluster should come on. Release parking brake. Light should go out. If light does not operate as specified, repair parking brake warning light circuit.
- If light operates as specified, check parking brake input signal circuit. See INPUT SIGNAL CIRCUITS . If input signal circuit is okay, perform next procedure listed in DIAGNOSIS BY SYMPTOM table under TROUBLE SHOOTING.
- If input signal circuit is not okay, remove cruise control ECU, but leave electrical connector(s) attached. Turn ignition on. Measure voltage between ground and terminal No. 3 of cruise control ECU connector. See Figure.
- With parking brake applied, voltage should be less than 2 volts. With parking brake released, battery voltage should be present. If voltage is as specified, perform next procedure listed in DIAGNOSIS BY SYMPTOM table under TROUBLE SHOOTING.
- If voltage is not as specified, check for faulty circuit between cruise control ECU and brake warning light. Repair circuit if necessary. If circuit is okay, replace cruise control ECU.