Electronic Control Unit (Ecu)
- Diagnosis of fuel injection system is accomplished by removing connector from ECU and checking all electric circuits ending at connector. The tests will indicate condition of components and wiring leading to tested terminal or sensor.
- If there is a problem after all tests are completed, and no malfunction was found, the ECU is most likely at fault. Replace the ECU and recheck system to ensure that the problem has been resolved.
- Always check and repair all circuits before substituting a new control unit. If a new control unit is installed first, a faulty circuit may destroy new control unit in same manner as old one. There is no testing procedure for the ECU other than substitution.
- To gain access to the ECU and harness connector, remove kick panel located in front of right front door. Disconnect wiring harness from ECU by pressing up on lock spring on top end of connector while pulling outward and down on top of connector. Do not pull connector straight out. See Fig 1.
- The connector terminals are now accessible, but should not be used for testing on their front side. The front of the connector terminals can easily be damaged by test equipment.
- To perform tests, cut boot clamp off of end of connector and slide cover off of connector. Always test from backside of connector. Terminal numbers are shown on both sides of connector. See Fig 2.
CAUTION:
DO NOT use test connector located behind battery. Special test equipment is required to use this connector and damage could result from using improper equipment.