| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuits are okay. If either are defective, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES - IMPORT article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. |
Note. For component location, see appropriate illustration in THEORY & OPERATION article.
Circuit Description
Stoplight switch may also be referred to as brake switch. Stoplight switch signal is used to detect when brakes have been applied. ECM uses this signal to control fuel cut-off engine speed. DTC is set if stoplight switch does not turn off when vehicle is being driven. Possible causes are
- Stoplight switch signal circuit is shorted.
- Defective stoplight switch.
- Defective ECM.
Diagnostic Aids
Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.