Code 3: Map Sensor
- Turn ignition off. Remove BACK UP fuse at battery positive terminal for 10 seconds to reset ECU. Check ECU for fault codes. See RETRIEVING CODES
. If Code 3 is not present, problem is intermittent. Check for poor or loose connections at MAP sensor and ECU. Test drive vehicle and retest.
- If Code 3 is present, turn ignition off. Disconnect 3-wire MAP sensor connector. Turn ignition on. Measure voltage between MAP sensor Yellow/Red (positive) wire and body ground. See Fig 1
. If voltage is about 5 volts, go to step 4). If voltage is not about 5 volts, 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. Measure voltage between test terminals D19 (+) and D21 (-). If about 5 volts are present, repair open circuit in D19 (Yellow/Red wire) between ECU connector and MAP sensor. If about 5 volts are not present, substitute a known good ECU. If problem goes away, replace ECU.
- If voltage is about 5 volts in step 2), measure voltage between Yellow/Red (+) and Green/White (-) wires at MAP sensor. If about 5 volts are not present, repair open in Green/White wire between ECU terminal D21 and MAP sensor. If voltage is about 5 volts, measure voltage between White (+) and Green/White (-) terminal at MAP sensor.
- If voltage is about 5 volts, go to step 6). If voltage reading is not about 5 volts, measure voltage between test harness terminals D17 and D21. See Figure
. If about 5 volts are present, repair open or short in circuit D17 (White wire) between ECU connector and MAP sensor. If voltage is not about 5 volts, substitute a known good ECU, and recheck. If about 5 volts are present, replace original ECU. If about 5 volts are not present, replace MAP sensor.
- Turn ignition off. Reconnect 3-wire 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 about 3 volts are not present, replace MAP sensor. If about 3 volts are present, substitute a known good ECU. If system functions properly, replace ECU. If about 3 volts are not present, replace MAP sensor.