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Code 3 - Map Sensor

  1. Turn off ignition. Remove HAZARD fuse in main fuse box for 10 seconds to reset ECU. Start engine. Verify if CHECK ENGINE light is on and if LED is flashing Code 3. If LED is flashing Code 3, go to next step. If LED is not flashing Code 3, problem is intermittent. Check connectors at MAP sensor and ECU.
  2. Turn ignition off. Disconnect 3-wire MAP sensor connector. Turn ignition on. Measure voltage between Yellow/Red (positive) terminal and ground. If reading is about 5 volts, go to step 4).
  3. If reading is not approximately 5 volts, check for open in Yellow/Red (positive) between ECU terminal C15 and MAP sensor. If wire is okay, substitute a known good ECU and recheck. If specified voltage is available now, replace original ECU.
  4. Measure voltage between Yellow/Red (positive) and Green/White (negative) terminals. If voltage is about 5 volts, go to step 5). If reading is not about 5 volts, check for open in Green/White wire between ECU terminal C14 and MAP sensor. If wire is okay, substitute a known good ECU and recheck. If specified voltage is now present, replace original ECU.
  5. If voltage reading is about 5 volts, measure voltage between White (positive) and Green/White (negative) terminals. If reading is not about 5 volts, go to step 7). If measured voltage is about 5 volts, turn ignition off. Reconnect 3-wire MAP sensor connector. Connect ECU Test Harness between ECU and ECU connector. See Figure . Turn ignition on. Measure voltage between terminal C11 (positive) and C14 (negative). If there is not about 3 volts present, replace MAP sensor.
  6. If there is about 3 volts present between C11 and C14, substitute a known good ECU and recheck. If specified voltage is now available, replace original ECU.
  7. If voltage measured in step 5) was not about 5 volts, repair open or short in White wire between ECU terminal C11 and MAP sensor. If wire is okay, substitute a known good ECU and recheck. If specified voltage is now available, replace original ECU.
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