| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Circuit Description
The stoplight 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
- Short in stoplight switch signal circuit.
- Stoplight switch.
- ECM.