Reading and Clearing Diagnostic Trouble Codes

Fig. 241 Connecting a voltmeter to the diagnostic connector.:

Fig. 257 Location of diagnostic connector.:

1. Turn the ignition key `OFF'.
2. Connect an analog voltmeter set to read 0 to 12 vdc to the diagnostic connector, Fig. 241 located behind the glove compartment, Fig. 257.

Fig. 243 Diagnostic code table.:

3. Turn the ignition key on and note the indication of the volt meter. If the voltmeter indicates a steady 12 vdc the ECU has failed. If the voltmeter fluctuates, note the position and width of pulses and compare the pattern to the diagnostic failure code chart to determine the error code, Fig. 243.

Note: There may be more than one error code stored in the ECU memory. If so they will be displayed in ascending order with a 2 second pause between each code. Also, the oxygen sensor code is erased when the ignition is turned off. To test for oxygen sensor codes drive the vehicle a significant distance and check for diagnostic codes before turning the ignition off.



4. After the cause of a failure code has been detected and corrected the diagnostic code memory of the ECU should be cleared by disconnecting the vehicle battery for 15 seconds or more. NOTE! Do not disconnect the vehicle battery while the engine is running or while the ignition is on.