PGM-FI System

DTC Troubleshooting (cont'd)

11-536  

  1. Check for continuity between the ECM/PCM connector terminal A1 and body ground.

ECM/PCM CONNECTOR A (31P)

Wire side of female terminals

Is there continuity?

YES

- Repair short in the wire between the ECM/PCM (A1) and the primary HO2S (Sensor 1).

NO

- Substitute a known-good ECM/PCM and recheck. If the symptom/indication goes away, replace the original ECM/PCM.


  1. Measure voltage between the primary HO2S (Sensor 1) 4P connector terminal No. 4 and body ground.

PRIMARY HO2S (SENSOR 1) 4P CONNECTOR

Terminal side of male terminals

Is there battery voltage?

YES

- Go to step 13.

NO

- Check the No. 4 ACG (10A) fuse in the under-dash fuse/relay box. If the fuse is OK, repair open in the wire between the primary HO2S (Sensor 1) and No. 4 ACG (10A) fuse.


  1. Turn the ignition switch OFF.
  1. Reconnect the primary HO2S (Sensor 1) 4P connector.
  2. Disconnect ECM/PCM connector A (31P).
  3. Turn the ignition switch ON (II).
  4. Measure voltage between the ECM/PCM connector terminal A1 and A5.

ECM/PCM CONNECTOR A (31P)

Wire side of female terminals

Is there 0.1 V or less?

YES

- Repair open in the wire between the ECM/PCM (A1) and the primary HO2S (Sensor 1).

NO

- Substitute a known-good ECM/PCM and recheck. If symptom/indication goes away, replace the original ECM/PCM.