Precautions in Diagnosing Trouble
WARNING: This page is about a different car, the 2004 Suzuki Grand Vitara. However, it is still accessible from the selected car via links, so may be relevant.
- Do not disconnect couplers from PCM, battery cable from battery, PCM ground wire harness from engine or main fuse before checking the diagnostic information (DTC, freeze frame data, etc.) stored in PCM memory. Such disconnection will clear memorized information in PCM memory.
- Using SUZUKI scan tool or OBD-II generic scan tool, the diagnostic information stored in PCM memory can be checked and cleared as well. Before its use, be sure to read Operator's (Instruction) Manual supplied with it carefully to have good understanding of its functions and usage.
- Priorities for diagnosing troubles:
If two or more DTCs are stored, proceed to the diagnostic procedure of the DTC which was detected earliest in the order and follow the instruction in that procedure.
If no instructions are given, troubleshoot diagnostic trouble codes according to the following priorities.
- DTCs other than DTC P0171/P0172/P0174/P0175 (Fuel system too lean/too rich), DTC P0300/P0301/P0302/P0303/P0304/P0305/P0306 (Misfire detected) and DTC P0401/P0402 (EGR flow Insufficient Detected/Excessive Detected)
- DTC P0171/P0172/P0174/P0175 (Fuel system too lean/too rich) and DTC P0401/P0402 (EGR flow Insufficient Detected/Excessive Detected)
- DTC P0300/P0301/P0302/P0303/P0304/P0305/P0306 (Misfire detected)
- PCM replacement:
When substituting a known-good PCM, check for the following conditions.
Neglecting this check may result in damage to a good PCM.
- All relays and actuators have resistance of specified value.
- MAF sensor, Manifold absolute pressure (MAP) sensor, TP sensor and fuel tank pressure sensor are in good condition. Also, the power circuit of these sensors is not shorted to the ground.