Possible causes
– Skid Control ECU / Engine Control Module (ECM) harness is open or shorted
– Skid Control ECU / Engine Control Module (ECM) circuit poor electrical connection
– Faulty Skid Control ECU
– Faulty Engine Control Module (ECM)
– Skid Control ECU / Engine Control Module (ECM) circuit poor electrical connection
– Faulty Skid Control ECU
– Faulty Engine Control Module (ECM)
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P1631 TOYOTA OBD Code Description
The Skid Control Electronic Control Unit (ECU) sends signals such as cruise control cancel demand signals and brake operation demand from Engine Control Module (ECM) response signals to the ECM when the cruise control system is in operation.