Precautions for Diagnosing Trouble

Precautions for Diagnosing Trouble

- Don't disconnect ECM connectors from ECM, battery cable from battery, ECM ground wire harness from engine, main fuse, "DOME" fuse or "B/U" fuse before confirming diagnostic information (pending DTC, confirmed DTC, freeze frame data, etc.) other than permanent DTC stored in ECM memory. Such disconnection erases memorized information in ECM memory if battery is disconnected before main relay is turned off.
- Diagnostic information stored in ECM memory can be cleared as well as checked by using SUZUKI scan tool or CAN communication OBD generic scan tool.
However, for the permanent DTC, it cannot be cleared by using SUZUKI scan tool or CAN communication OBD generic scan tool. (For details of permanent DTC, refer to On-Board Diagnostic (OBD) System Description On-Board Diagnostic (OBD) System Description.)
Before using scan tool, read its Operator's (Instruction) Manual carefully to have good understanding as to what functions are available and how to use it.
It is unable to distinguish which module, ECM or TCM turns on MIL. (For details of on-board diagnostic system for A/T model, refer to On-Board Diagnostic System Description On-Board Diagnostic System Description
). Therefore, check both ECM and TCM for DTC when MIL lights on.

- When checking ECM for DTC, keep in mind that DTC is displayed on the scan tool as follows depending on the scan tool.

- SUZUKI scan tool displays DTC detected by ECM.
- CAN communication OBD generic scan tool displays DTC detected by both ECM and TCM simultaneously.

- Priorities for diagnosing troubles
If two or more 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.

a DTCs other than DTC P0171 / P0172 (Fuel system too lean/too rich) and DTC P0300 / P0301 / P0302 / P0303 / P0304 (Misfire detected)
b DTC P0171 / P0172 (Fuel system too lean/too rich)
c DTC P0300 / P0301 / P0302 / P0303 / P0304 (Misfire detected)

- Be sure to read Precaution for CAN Communication System Precaution for CAN Communication System
before inspection and observe what is written there.
- ECM Replacement
When ECM is replaced with new one or substituted one, check for the following conditions. Neglecting this check may cause damage to ECM.

- Resistance value of all relays and actuators are as specified respectively.
- APP sensor, TP sensor and A/C refrigerant pressure sensor are in good condition and none of power circuits of these sensors is shorted to ground.

- Communication of ECM, BCM, combination meter, keyless start control module, ABS / ESP(R) control module, 4WD control module, steering angle sensor (ESP(R) model) and TCM, is established by CAN (Controller Area Network). (For more detail of CAN communication for ECM, refer to Description and Operation Battery Description
).
Therefore, handle CAN communication line with care referring to Precaution for CAN Communication System Precaution for CAN Communication System.
- For immobilizer model, immobilizer transponder code registration after replacing ECM.
When ECM is replaced with new one or substituted one, make sure to register immobilizer transponder code. Registration of the Ignition Key
- For EVAP-leak-check model, VIN (vehicle identification number) data registration after replacing ECM.
When ECM is replaced with new one (VIN data is still not registered) or with used one (VIN data of other vehicle has been registered previously), make sure that re-register VIN data correctly by performing Programming and Relearning VIN (Vehicle Identification Number) Registration (EVAP-Leak-Check Model).