Faulty Powertrain Control Module (PCM)
Powertrain Control Module (PCM) harness is open or shorted
Powertrain Control Module (PCM) circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
The control program in the Powertrain Control Module (PCM) has a rewriting function that can be done in the field. The programs in the PCM CPU are the powertrain control program (rewritable program) and the update program (non-rewritable program). When the program rewriting process is not finished normally, such as turning off the PCM power during the rewriting process, and then turning the ignition switch to ON (II) again, the A/T CPU starts according to the rewriting function program, and this Diagnostic Trouble Code (DTC) is sent to the FI CPU via serial communication and stored in the PCM.