Code 5: Map Sensor
- Turn ignition off. Remove BACK UP fuse from underhood fuse/relay box for 10 seconds to reset ECU. Start engine, and observe CHECK ENGINE light. If light is off, problem is intermittent. Check all electrical connections and vacuum hoses. Test drive vehicle and retest.
- If CHECK ENGINE light is on and indicates Code 5, turn ignition off. Connect hand-held vacuum pump to MAP sensor hose at throttle body. See Fig 1
. Apply vacuum. If vacuum holds, go to next step. If vacuum does not hold, attach vacuum pump to MAP sensor. Apply vacuum. If vacuum does not hold, replace MAP sensor. If vacuum holds, check MAP sensor vacuum hose for cracks, splits and looseness. Repair as necessary.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
- Connect "T" fitting in vacuum hose between MAP sensor and throttle body. Start engine. If vacuum is not present, remove restriction from throttle body. If vacuum is present, turn ignition off. 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 voltage reading is about 3 volts, start engine, and allow it to idle. Recheck voltage between terminals D17 and D21. If voltage is not 1.0 volt at idle, replace MAP sensor. If voltage is about 1.0 volt, substitute a known good ECU. If symptom/condition goes away, replace ECU.