With Honda PGM Tester or OBDII Scantool

When the TCM senses an abnormality in the input or output systems, the D4 indicator light in the gauge assembly will blink. When the 16P Data Link Connector (DLC) (located behind the ashtray) is connected to the OBD-II Scan Tool or Honda PGM Tester as shown, the scan tool or tester will indicate the Diagnostic Trouble Code (DTC) when the ignition switch is turned ON (II).

When the D4 indicator light has been reported on, connect the OBD-II Scan Tool conforming to SAE J1978 or Honda PGM Tester to the DLC (16P) behind the ashtray. Turn the ignition switch on (II) and observe the DTC on the screen of the OBD-II Scan Tool or Honda PGM Tester. After determining the DTC, refer to the electrical system Diagnosis By Symptom / Symptom-to-Component Chart. Testing and Inspection

NOTE: See the OBD-II Scan Tool or Honda PGM Tester user's manual for specific instructions.

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 TCM memory, then retest.

NOTE: Disconnecting the BACK UP fuse also cancels the radio anti-theft code, preset stations and the clock setting. Get the customer's code number, and make note of the radio presets before removing the fuse so you can reset them.