Precautions in Diagnosing Trouble

Precautions in Diagnosing Trouble

- Do not disconnect connectors from TCM, battery cable from battery, TCM ground wire harness from engine or main fuse before checking the diagnostic information (pending DTC, confirmed DTC, freeze frame data, etc.) other than permanent DTC stored in TCM memory. Such disconnection will clear memorized information in TCM memory.
- Diagnostic information stored in TCM 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 cannot be cleared by using SUZUKI scan tool or OBD-II generic scan tool. (For details of permanent DTC, refer to On-Board Diagnostic System Description 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. Therefore, check both ECM and TCM for DTC when MIL lights on.
When checking TCM 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 TCM.
- OBD-II generic scan tool displays DTC detected by each of ECM and TCM simultaneously.

- When replacing TCM with used one, all learned controls which are stored in TCM memory should be erased after the replacement referring to Programming and Relearning TCM Learning Control Initialization. Neglecting this initialization may cause excessive shift shock.
- Be sure to read Precautions for Electrical Circuit Service Precautions for Electrical Circuit Service
before inspection and observe what is written there.
- TCM and/or ECM replacement:
When substituting a known-good TCM and/or ECM, check for the following conditions.
Neglecting this check may result in damage to a good TCM and/or ECM.

- All relays and actuators have resistance of specified value.
- MAF and IAT 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.

- Communication of ECM, TCM, BCM, combination meter, keyless start control module (if equipped), ABS / ESP(R) control module, 4WD control module (if equipped), HVAC control module, steering angle sensor (ESP(R) model) and DLC, is established by CAN (Controller Area Network). (For more detail of CAN communication for ECM, refer to CAN Communication System Description CAN Communication System Description
). Therefore, handle CAN communication line with care referring to Precaution for CAN Communication System Precaution for CAN Communication System.