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Code 13 - Atmospheric Pressure Pa Sensor

  1. Turn ignition off. Remove No. 11 fuse in the under-hood relay box 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.
  2. If light is on, turn ignition off. Connect ECU test harness between ECU and ECU connector. See Figure . Turn ignition on. Measure voltage between terminals C13 (pos.) and C12 (neg.). If about 5 volts is read, go to step 3). If not, substitute a known good ECU. If correct voltage is now indicated, replace original ECU.
  3. Measure voltage between terminals C9 (pos.) and C12 (neg.). If about 3 volts is not present, go to step 4). If about 3 volts is present, substitute a known good ECU. If condition is rectified, replace original ECU.
  4. Disconnect connector from atmospheric pressure sensor. Measure voltage between terminals C9 (pos.) and C12 (neg.) on harness side. If about 5 volts is indicated, go to step 5). If about 5 volts is not indicated, repair short in Yellow/White wire, between ECU terminal C9 and sensor.
  5. Measure voltage between Yellow/White and Green/White (neg.) wires. If reading is not about 5 volts, go to step 6). If about 5 volts is present, measure voltage between Red and Green/White (neg.) terminals. If about 5 volts is not read, repair open Red or Red/White wire between ECU terminal C9 and sensor. If about 5 volts is read, replace sensor.
  6. Measure voltage between ground and Yellow/White wire of harness. If about 5 volts is not present, repair open in White/Yellow or Yellow/White wire between ECU terminal C13 and sensor. If about 5 volts is present, repair open Green/White wire between ECU terminal C12 and sensor.
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