Code 3 - Map Sensor
- Turn ignition switch off and remove hazard fuse at battery positive terminal for 10 seconds to reset ECU. Start engine and observe Check Engine light. If light is off, problem is intermittent. Test drive and check again.
- If light is on, turn ignition off. Disconnect 3-wire MAP sensor connector. Turn ignition on. Measure voltage between Red (pos.) and Brown/White (neg.) terminals. Go to step 4) if reading is about 5 volts. If not, measure voltage between Red (pos.) terminal and ground. If voltage is still not 5 volts, go to step 3). If voltage is about 5 volts, repair open in Brown/White wire between ECU terminal C14 and MAP sensor.
- Turn ignition off. Connect system checker harness between ECU and ECU connector. Measure voltage between terminal C15 (pos.) and C14 (neg.) with ignition on. If voltage reading is about 5 volts, repair open Red wire between ECU terminal C15 and MAP sensor. If voltage is not about 5 volts, substitute a known good ECU. If condition is rectified, replace original ECU.
- Measure voltage between White (pos.) and Brown/White (neg.) terminals. If reading is not about 5 volts, go to step 6). If measured voltage is about 5 volts, turn ignition off. Connect system checker harness between ECU and ECU connector. Reconnect 3-wire MAP connector. Turn ignition on. Measure voltage between terminal C11 (pos.) and C14 (neg.). If there is not about 5 volts present, replace MAP sensor.
- If there is about 5 volts present between C11 and C14, substitute a known good ECU. If condition is rectified, replace original ECU.
- If voltage measured between White (pos.) and Brown/White (neg.) terminals in step 4) was not about 5 volts, turn ignition off. Connect system checker harness between ECU and ECU connector. Turn ignition on. Measure voltage between terminals C11 (pos.) and C14 (neg.). If reading is not about 5 volts, repair short in White wire between ECU terminal C11 and MAP sensor. If voltage is about 5 volts, repair open in White wire between ECU terminal C11 and MAP sensor.