There are codes in memory
If the presence of one or more fault codes is detected, then refer to the table of fault codes at the end of the chapter to determine their meaning.
If there are multiple codes, check for a general fault, such as a ground or power supply fault.
If you need to check any parts and circuits related to the engine control system, refer to the parts check procedures described earlier.
After troubleshooting, clear the codes and run the engine under various conditions to determine if the problem is resolved.
Check the ECU for fault codes again. If the codes still persist, repeat the above procedures. There are no codes in memory.
When there are problems during engine operation, but there are no fault codes in the memory, then the fault is outside the parameters provided for by the design of the self-diagnosis system.
If the problem is related to a specific part, then refer to the chapter, which describes the procedures for checking most parts and circuits related to the engine control system.