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P code powertrain High severity

P1106 Dual Alternator Lower Fault/ Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent High Voltage

The OBD2 code P1106 indicates a problem with the dual alternator system, specifically a lower fault, or an intermittent high voltage issue in the Manifold Absolute Pressure (MAP) sensor circuit

Definition

The OBD2 code P1106 indicates a problem with the dual alternator system, specifically a lower fault, or an intermittent high voltage issue in the Manifold Absolute Pressure (MAP) sensor circuit

Common causes

  • Faulty MAP sensor
  • Wiring issues (shorts or open circuits)
  • Corroded or loose connectors
  • Vacuum leaks
  • Faulty alternator or charging system issues
  • Engine control module (ECM) problems
  • Grounding issues
  • Intermittent electrical connections

Common misdiagnoses

  • Faulty MAP sensor
  • Vacuum leaks
  • Wiring issues or shorts in the MAP sensor circuit
  • Faulty engine control module (ECM)
  • Incorrectly installed or damaged intake manifold
  • Faulty alternator or charging system issues
  • Throttle position sensor (TPS) issues
  • Fuel pressure problems
  • Air intake system obstructions
  • Exhaust gas recirculation (EGR) system faults

Troubleshooting steps

  1. 1. Check the MAP Sensor:

    Visual Inspection: Inspect the MAP sensor for any physical damage, corrosion, or loose connections

  2. 2. Connector Check

    Ensure that the electrical connector is secure and free of dirt or moisture

  3. 3. Wiring Inspection

    Look for damaged or frayed wires leading to the MAP sensor

  4. 4. Test the MAP Sensor:

    Voltage Test: Use a multimeter to check the voltage output of the MAP sensor. Compare the readings to the manufacturer's specifications

  5. 5. Resistance Test

    Measure the resistance of the MAP sensor to ensure it is within the specified range

  6. 6. Vacuum Test

    If applicable, check the vacuum signal to the MAP sensor to ensure it is receiving the correct input

  7. 7. Check the Alternator:

    Dual Alternator System: If your vehicle has a dual alternator setup, ensure both alternators are functioning correctly

  8. 8. Voltage Output

    Measure the voltage output of both alternators to ensure they are within the specified range

  9. 9. Connections

    Inspect the wiring and connections to both alternators for any signs of wear or damage

  10. 10. Inspect the Powertrain Control Module (PCM):

    Software Updates: Check if there are any available software updates for the PCM that may address this issue

  11. 11. Fault Codes

    Scan for any additional fault codes that may provide more context to the problem

  12. 12. Check for Ground Issues:

    Ground Connections: Inspect all ground connections related to the MAP sensor and alternators. A poor ground can cause high voltage readings

  13. 13. Continuity Test

    Perform a continuity test on ground wires to ensure they are functioning properly

  14. 14. Look for Vacuum Leaks:

    Intake System Inspection: Inspect the intake manifold and associated hoses for any vacuum leaks that could affect MAP sensor readings

  15. 15. Smoke Test

    Consider performing a smoke test to identify any hidden vacuum leaks

  16. 16. Clear Codes and Test Drive:

    After performing the above checks and repairs, clear the trouble codes using an OBD-II scanner

  17. 17. Take the vehicle for a test drive to see if the code reappears

  18. 18. Professional Diagnosis:

    If the issue persists after performing these steps, consider seeking help from a professional mechanic or technician who has experience with your specific vehicle make and model. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P1106 code