Precautions for Diagnosing Trouble
- Do not disconnect ECM connectors from ECM, battery cable from battery, ECM ground wire harness from engine, "B/U" fuse or "DOME" fuse before confirming diagnostic information (pending DTC, confirmed DTC, freeze frame data, etc.) other than permanent DTC stored in ECM memory. Such disconnection will erase memorized information in ECM memory.
- Before using scan tool, read its "Operator's (Instruction) Manual" to know how to use it.
- Priorities for diagnosing troubles
If two or more diagnostic trouble codes (DTCs) are stored, proceed to the flow of the DTC which has detected earliest in the order and follow the instruction in that table.
If no instructions are given, troubleshoot DTCs according to the following priorities.
- DTCs other than DTC P0171/P0172 (Fuel system too lean/too rich) and DTC P0300/P0301/P0302/P0303/P0304 (Misfire detected)
- DTC P0171/P0172 (Fuel system too lean/too rich)
- DTC P0300/P0301/P0302/P0303/P0304 (Misfire detected)
- Upon completion of inspection and repair work, perform "DTC Confirmation Procedure" and confirm that the trouble has been repaired.
- Be sure to clear all DTCs after completing troubleshooting.