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Home >> Acura >> 1991 >> Legend Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Code 5: Map Sensor
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Code 5: Map Sensor

NOTE: For wiring diagrams, see WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section. For vacuum diagrams, see VACUUM DIAGRAMS article in the ENGINE PERFORMANCE Section.
  1. Turn ignition off. Remove ACG fuse in underdash fuse box for 10 seconds to reset ECU. Start engine, and connect jumper wire to diagnostic connector. Observe CHECK ENGINE light. If light is not flashing, problem is intermittent. Check vacuum hose No. 21 for cracks, leaks and crimping. Test drive, and check again.
  2. If CHECK ENGINE light flashes Code 5, turn ignition off. Using a "T" fitting, connect a hand-held vacuum pump/gauge between MAP sensor vacuum hose and hose from vacuum manifold. Start engine. If vacuum is not present, check hoses, and repair as necessary. If hoses are okay, replace MAP sensor. If vacuum is present and holds, turn ignition off.
  3. Connect a hand-held vacuum pump to hose No. 21, and apply vacuum. If vacuum does not hold, check hose No. 4, and replace as necessary. If vacuum holds, connect ECU Test Harness (07LAJ-PT3010A) between sensor and harness. Turn ignition on.
  4. Measure voltage between D17 (positive) and D21 (negative) wire terminals. If about 3 volts are not present, replace MAP sensor. If about 3 volts are present, start engine, and check voltage at idle. If voltage is about 1 volt, substitute a known good ECU. If system operates properly, replace original ECU. If voltage is not about 1 volt, replace MAP sensor.
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