Computers and Control Systems: Service Precautions
General DescriptionCAUTION
1. Airbag system wiring harness is routed near the ECM, main relay and fuel pump relay.
CAUTION:
- Do not use electrical test equipment on the airbag system circuit.
- Be careful not to damage the airbag system wiring harness when servicing the ECM, TCM, main relay and fuel pump relay.
2. Never connect the battery in reverse polarity. Doing so will damage the ECM instantly, and other parts will also be damaged.
3. Do not disconnect the battery terminals while the engine is running. A large counter electromotive force will be generated in the generator, and this voltage may damage electronic parts such as ECM etc.
4. Before disconnecting the connectors of each sensor and ECM, be sure to turn the ignition switch to OFF. Perform the Clear Memory Mode after connecting the connectors.
5. Measure the voltage or resistance of individual sensor or all electrical control modules using a tapered pin with a diameter of less than 0.6 mm (0.024 in). Do not insert the pin 4 mm (0.16 in) or more into the part.
CAUTION: When replacing the ECM, be careful not to use the wrong spec. ECM to avoid any damage on the fuel injection system.
NOTE: When replacing the ECM of the models with Immobilizer, immobilizer system must be registered. To do so, all ignition keys and ID cards need to be prepared. For detailed operation procedures, refer to "PC application help for Subaru Select Monitor".
6. Take care not to allow water to get into the connectors when servicing or washing the vehicle in rainy weather. Avoid exposure to water even if the connectors are waterproof.
7. Use ECM mounting stud bolts at the body side grounding point when measuring voltage and resistance inside the passenger compartment.
8. Use the engine ground terminal or engine assembly for the grounding point to chassis when measuring the voltage and resistance in engine compartment.
9. Every engine control system-related part is a precision part. Do not drop them.
10. Observe the following cautions when installing a radio in vehicle.
CAUTION:
- The antenna must be kept as far apart as possible from control module. (ECM is installed under the passenger's side floor mat.)
- The antenna feeder must be placed as far apart as possible from the ECM and engine control system harness.
- Carefully adjust the antenna for correct matching.
- When mounting a large power type radio, pay special attention to the three items mentioned above.
- Incorrect installation of the radio may affect the operation of ECM.
11. When disconnecting the fuel hose, release the fuel pressure.
12. Warning lights may illuminate when performing driving test with jacked-up or lifted-up condition, but this is not a system malfunction. The reason for this is the speed difference between the front and rear wheels. After diagnosis of engine control system, perform the ABS memory clear procedure of self diagnosis function.