Reading Diagnostic Trouble Codes

TROUBLESHOOTING PROCEDURES
When the A/T control unit senses an abnormality in the input or output systems, the D4 indicator light in the gauge assembly will blink. However, when the Service Check Connector (located to the lower right of the glove compartment) is connected with a jumper wire, the D4 indicator light will blink the problem code when the ignition switch is turned on.

When the D4 indicator light has been reported on, connect the two terminals of the Service Check Connector together. The turn on the ignition switch and observe either the D4 indicator light.





Problem codes 1 through 9 are indicated by individual short blinks, Problem codes 10 through 15 are indicated by a series of long and short blinks. One long blink equals 10 short blinks. Add the long and short blinks together to determine the problem code. After determining the problem code, refer to the electrical system Diagnosis By Symptom / Symptom-to-Component Chart. Testing and Inspection





Some PGM-FI problems will also make the D4 indicator light come on. After repairing the PGM-FI system, disconnect the Back Up fuse (7.5 A) in the under-hood fuse/relay box for more than 10 seconds to reset the A/T control unit memory.

NOTE: Disconnecting the Back up fuse also cancels the radio preset stations and the clock setting. Make note of the radio presets before removing the fuse so you can reset them.





NOTE:
- Only the A and 0 sections of the Test Harness are used for A/T troubleshooting.
- Unless otherwise noted, use only the Digital Multimeter, KS-AHM-32-003, for testing.