Code 5 - Map Sensor
- Turn ignition off. Remove BACK-UP fuse in the under-hood relay box for 10 seconds to reset ECU. Start engine. Verify if CHECK ENGINE light is on and if LED is flashing Code 5. If LED is flashing Code 5, go to next step. If LED is not flashing Code 5, problem is intermittent. Check vacuum hoses, pipes and connections. Ensure all connectors are secure.
- Turn ignition off. Connect a hand-held vacuum pump/gauge into vacuum hose at throttle body (vacuum hose No. 21). Apply vacuum. If vacuum does not hold, attach vacuum pump/gauge directly to MAP sensor. Apply vacuum. If vacuum does not hold, replace MAP sensor. If vacuum holds, proceed to next step.
- Connect a "T" fitting between throttle body and MAP sensor. Check vacuum supply to MAP sensor with engine running. If vacuum is not present, repair hose or clear restriction from throttle body. If vacuum supply is okay, turn ignition off.
- Connect ECU Test Harness between ECU and ECU connector. See Figure . Measure voltage between positive terminal D17 and negative terminal D21. If voltage reading is about 3 volts, go to next step. If voltage is not about 3 volts, replace MAP sensor.
- Start engine and let idle. If voltage is not about 1 volt, replace MAP sensor. If voltage reading is about 1 volt, substitute a known good ECU. If condition is corrected, replace original ECU.