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.

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.
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.
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.
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.

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.

Safety Warning

Code 5: Map Sensor

Use the Manual With the Right Hardware

When to See a Mechanic

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