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Code 3: Map Sensor

WARNING: This page is about a different car, the 1992 Acura Legend. However, it is still accessible from the selected car via links, so may be relevant.
  1. 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.
  2. 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.
    Fig 1: MAP Sensor Connector Terminal ID
    G92E26207Courtesy of AMERICAN HONDA MOTOR CO., INC.
  3. 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.
  4. 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.
  5. 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 .
  6. 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.
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