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 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.
- Diagnostic information stored in ECM memory can be cleared as well as checked by using SUZUKI scan tool or OBD-II generic scan tool. However, for the permanent DTC, it can not be cleared by using SUZUKI scan tool or OBD-II generic scan tool. (For details of permanent DTC, refer to OBD (On-Board Diagnostic) System Description OBD (On-Board Diagnostic) 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 indistinguishable which module turns on MIL because not only ECM but also TCM turns on MIL (For details of on-board diagnostic system for CVT 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 used.

- SUZUKI scan tool displays DTC detected by ECM.
- OBD-II generic scan tool displays DTC detected by each of ECM and TCM simultaneously.

- 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.

a Diagnostic trouble codes (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 Technician Safety Information Precaution for CAN Communication System
before inspection and observe what is written there.
- ECM Replacement
When substituting a known-good ECM, check for the following conditions. Neglecting this check may cause damage to known good ECM.

- Resistance value of all relays, actuators is as specified respectively.
- APP sensor, TP sensor, A/C refrigerant pressure sensor and EVAP leak check pressure sensor (EVAP-leak-check model) 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 (keyless start model), ABS / ESP(R) control module, 4WD control module (4WD model), steering angle sensor (ESP(R), model) yaw rate / G sensor (ESP(R) model), TCM (CVT model), SDM (Advanced air bag model) and ID controller (Canada model), is established by CAN (Controller Area Network). (For more detail of CAN communication for ECM, refer to Description and Operation CAN Communication System Description
).
Therefore, handle CAN communication line with care referring to Technician Safety Information 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
- VIN (vehicle identification number) data registration after ECM replacement (EVAP-leak-check-model)
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 Registration (EVAP Leak Check Model).
Otherwise, MIL remains on even if the engine started or it causes the inconsistency between registered VIN data in ECM and actual VIN.