What does the P0106 OBD-II code mean?

The P0106 trouble code generally means an issue with the MAP circuit having incorrect output range issues or a problem with engine performance. The diagnostic code is set when either the Power Train Control Module (PCM) detects an abnormal signal voltage from the Manifold Absolute Pressure (MAP) sensor relating to the current throttle position or engine load or a signal voltage that does not show a good relationship with the MAP sensor. The MAP sensor is integral to the fuel injection system, providing signals to the Engine Control Unit (ECU) to allow smooth operation, good fuel economy, and proper performance and power. The P0106 diagnostic code is generally activated more commonly on vehicles with higher mileage of over 100,000 miles. 

How serious is the P0106 code?

Triggering a P0106 OBD-II error code is a serious problem. If there are issues with your system’s sensors giving incorrect readings, it can prevent your engine from running smoothly, including backfiring, which is a severe problem. It will also cause hesitation on acceleration and general poor engine running, and excessive fuel consumption. Therefore, it’s crucial to identify the problem as soon as possible, as driving the vehicle with this issue may cause engine damage.

What are the common symptoms of a P0106 trouble code?

When a P0106 code is triggered, the symptoms are usually the same on all applications. However, the severity may vary from vehicle to vehicle. Common symptoms include, but are not limited to:

  • Check Engine Light illuminated
  • Hesitation upon acceleration and generally poor idling and running
  • Backfire due to the MAP sensor and throttle position sensor not operating together
  • Increased fuel consumption

What are the causes of a P0106 OBD-II code?

There are numerous causes of the P0106 trouble code, with many triggered by unrelated faults:

  • Air intake system vacuum or intake leak caused by loose hose, missing or broken plastic fittings and clamps (common)
  • Wiring
  • Clogged catalytic converter(s)
  • Severe or prolonged misfires on a cylinder
  • Vacuum leaks due to poor maintenance
  • Throttle position sensor is defective
  • Faulty or malfunctioning mass airflow sensor
  • Exhaust Gas Recirculation valve is defective
  • Idle Air Control Motor is faulty

Additional causes that are related directly to the MAP sensor include:

  • Open, shorted, or damaged wiring
  • Defective BARO sensor (if fitted)
  • Defective MAP sensor
  • Unmetered air entering the inlet tract
  • Poor engine condition and insufficient fuel pressure can prevent the MAP sensor from getting a correct output
  • Power Train Control module failure (rare) 

How to diagnose a P0106 OBD-II code?

The easiest way to diagnose an OBD-II fault code is to use an OBD-II scanner or book a diagnostic check with a trusted mechanic or garage. The main point to remember is not to replace a MAP Sensor or ECU unless one is clearly at fault, which is determined by following the proper process:

  • See if there are any technical service bulletins available for your vehicle’s make and model to see if there is a known issue for your car that can help resolve the problem.
  • Scan your system for other OBD-II codes.
  • Clear the fault codes and take the car for a test drive while reading the live data on an OBD-II scanner.
  • If the code persists, perform a close inspection of the vacuum line and other hoses on the intake system to check for loose, damaged, disconnected or missing hoses or fittings.
  • While the engine is running, perform a voltage output test on the sensor to ascertain if the output voltages fluctuate with the load on the engine and engine speed.
  • Ensure all grounds are operating correctly (any ground related to the ECU may cause signal fluctuations from sensors).

How to fix a P0106 OBD-II code?

It is recommended to test drive the vehicle after each check/work is performed to see if the fault code clears. If the code returns, move on to the next repair. The most common repairs to resolve a P0106 are:

  • Verify the code with an OBD-II scanner, and reset the fault code. Follow this with a test drive of the car to see if the trouble code clears. If it returns:
  • Check the vacuum lines and intake hoses to ensure no missing, loose, cracked or detached parts.
  • Inspect the electrical wiring and connector.
  • Disconnect and then reinstall the electrical connector to ensure a good positive electrical connection.
  • Ensure the voltage output on the MAP sensor is in the correct range.
  • Determine if the MAP sensor is defective with incorrect or no output and replace if necessary.
  • The final test will be to determine if the ECU is defective.

How to avoid a P0106 Code?

It is common for older vehicles with higher mileage of over 100,000 miles on the clock will have momentary sensor problems. If the engine warning light comes on, but t