Code 3: Map Sensor
- Turn ignition off. Remove fuse No. 15 (ACG) from underdash fuse box for 10 seconds to reset ECU. Start engine, and connect jumper wire to self-diagnostic connector. Observe CHECK ENGINE light. If Code 3 is not present, problem is intermittent. Check for poor or loose connection at MAP sensor connector. Test drive vehicle and retest.
- If Code 3 is present, turn ignition off. Disconnect 3-wire connector at MAP sensor. Turn ignition on. Measure voltage between Yellow/White (+) terminal and body ground. If reading is about 5 volts, go to step 4). If reading is not about 5 volts, turn ignition off. Connect "D" connector of ECU Test Harness (07LAJ-PT3010A
) to ECU, leaving vehicle wiring harness disconnected.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
- Turn ignition on. If voltage is about 5 volts, repair open in Yellow/White wire between ECU terminal D19 and MAP sensor. If reading is not about 5 volts, turn ignition off. If voltage is not about 5 volts, substitute a known good ECU, and recheck. If voltage is now correct, replace original ECU.
- If voltage is about 5 volts in step 2), measure voltage between Yellow/White and Green/White wires at MAP sensor. See Fig 1
. If voltage is not about 5 volts, repair open in Green/White wire between ECU connector terminal D21 and MAP sensor. If voltage is about 5 volts, measure voltage between Red (+) and Green/White (-) terminal at MAP sensor.
- If reading is not about 5 volts, check for open or short in circuit D17 (Red wire) between ECU connector and MAP sensor. If circuit is okay, substitute a known good ECU. If condition goes away, replace original ECU. If voltage is about 5 volts, turn ignition off. Reconnect MAP sensor connector. Connect ECU Test Harness (07LAJ-PT3010A
) between ECU and ECU connector. See Figure
.
- Turn ignition on. Measure voltage between test terminals D17 (+) and D21 (-). If voltage is not about 3 volts, replace MAP sensor. If about 3 volts are present, substitute a known good ECU. If condition goes away, replace original ECU.