1993 Acura Legend Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Code 5: Map Sensor

  1. Turn ignition off. Remove ACG (No. 15, 7.5-amp) from underdash fuse box for 10 seconds to reset ECM. Start engine. Connect jumper wire to self-diagnostic connector. Observe MIL. If light is off, problem is intermittent. Check all electrical connections and vacuum hoses. Test drive vehicle and retest.
  2. If MIL is on and indicates Code 5, turn ignition off. Remove MAP hose at throttle body base. Connect a hand-held vacuum pump to MAP sensor, and apply vacuum. If vacuum does not hold, replace MAP sensor. If vacuum holds, connect vacuum hose and go to step 3.
  3. Connect "T" fitting in vacuum hose between MAP sensor and throttle body base. See Fig 1 . Start engine. If vacuum is not present, remove restriction from throttle body. If vacuum is present, turn ignition off. Connect ECM Test Harness (07LAJ-PT3010A ) between ECM and ECM connectors. See Figure . Turn ignition on. Measure voltage between test terminals D17 (+) and D21 (-).
  4. If voltage is not about 3 volts, replace MAP sensor. If voltage is about 3 volts, start engine and allow it to idle. Recheck voltage between terminals D17 and D21. If voltage is not about one volt at idle, replace MAP sensor. If voltage is about one volt, replace ECM and retest.
    Fig 1: Testing MAP Sensor
    G92B26212Courtesy of AMERICAN HONDA MOTOR CO., INC.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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