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Home >> Honda >> 1990 >> Prelude 2.0 S, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 2.0L PGM-CARBURETED >> Trouble Codes - PGM-Carb Control System >> Code 3 - Map Sensor

Code 3 - Map Sensor

  1. Turn ignition off. Remove EFI/ECU fuse in under-hood relay panel for 10 seconds to reset ECU. Start and warm engine to normal operating temperature. Verify if CHECK ENGINE light is on and if LED is flashing Code 3. If LED is not flashing Code 3, problem is intermittent. Test drive and check CHECK ENGINE light again.
  2. If LED is flashing Code 3, turn ignition off. Connect 3-wire Test Harness (07GMJ-ML80100 ) connector between MAP sensor and sensor harness. Turn ignition on. Measure voltage between Red (positive) and Green (negative) terminals. If reading is about 5 volts, go to step 3). If reading is not about 5 volts, measure voltage between Red (positive) terminal and ground.
  3. If measured voltage is approximately 5 volts, repair open in Green/White wire between ECU terminal D22 and MAP sensor. If voltage is not 5 volts, turn ignition off. Connect ECU Test Harness connector between ECU connectors. See Figure . Turn ignition on.
  4. Measure voltage between ECU terminal D20 (positive) and D22 (negative). If measured voltage is approximately 5 volts, repair open in Yellow/White wire between ECU terminal D20 and MAP sensor. If voltage is not 5 volts, substitute a known good ECU. If condition is corrected, replace original ECU.
  5. Measure voltage between White (positive) and Green (negative) terminals. If reading is not about 3 volts, replace MAP sensor or repair open or short in White/Blue wire between ECU terminal D17 and MAP sensor.
  6. If measured voltage is about 3 volts, turn ignition off. Connect ECU Test Harness connector between ECU connectors. See Figure . Turn ignition on. Measure voltage between terminals D17 (positive) and D22 (negative). If 3 volts are not present, repair open in White/Blue wire between ECU terminal D17 and MAP sensor. If not go to step 7).
  7. If 3 volts was present, substitute a good known ECU and retest. If condition is corrected, replace original ECU.
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