Manifold Absolute Pressure/Mass Air Flow - Throttle Position Correlation at Idle


This code indicates that inconsistencies have been detected in manifold absolute pressure and/or mass airflow voltage and throttle position for a period exceeding four-seconds continually. A code has been stored and a malfunction indicator lamp may be illuminated. Some manufacturers require multiple failure cycles in order for a malfunction indicator lamp to be illuminated.

Code Set Parameters

An unacceptable manifold absolute pressure and/or mass airflow voltage reading, for the degree of throttle requested, has been detected for a period exceeding four-seconds continually. This reading is measured against the manufacturer’s reference voltage.


Symptoms include failure to accelerate, decreased fuel efficiency, and possibly a service engine soon light.

Common Causes

Common causes of this code are a disconnected plug at the manifold absolute pressure and/or mass airflow sensor/s, moisture or debris that has contaminated the vane of the manifold absolute pressure and/or mass airflow sensor/s, a faulty manifold absolute pressure and/or mass airflow sensor, a cracked or broken air inlet pipe, clogged air filter element, a defective or misadjusted throttle position sensor, or faulty PCM. PCM failures are rare.

Common Misdiagnosis

Often expensive manifold absolute pressure and/or mass airflow sensors are replaced when a simple cleaning of the mass airflow sensor “hot wire” could rectify the condition. Corroded wiring and/or connectors have also been reported by technicians.


  • Several tools will be instrumental in attempting to successfully diagnose this code
  • A suitable OBD-II scanner (or code reader) and a digital volt/ohmmeter will be most helpful in trying to perform a successful diagnosis
  • Begin your diagnosis by visually inspecting all wiring and connectors
  • Look for shorted or burned wiring and replace circuitry and connectors as required
  • If the system wiring, connectors, and components appear to be in normal working order, connect the scanner to the diagnostic connector and record all stored trouble codes and freeze frame data
  • This information can be extremely helpful in diagnosing intermittent conditions that may have contributed to this code being stored
  • After the codes are cleared, operate the vehicle to see if the code returns
  • If the code fails to immediately return, you may have an intermittent condition
  • Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made. Determine whether there is a malfunction in MAF system circuitry, a problem with unmetered air entering the engine, or a problem with an insufficient air supply to the engine
  • Check for a clogged air filter element, broken, pinched, or disconnected air inlet pipe, or a vacuum leak prior to beginning an electrical diagnosis
  • If these items are found to be in proper working order, check for power and ground at the MAF sensor, as well as sensor voltage to the PCM
  • Visually inspect the vane or hot wire of the MAF itself for signs of foreign dirt or other debris
  • This can be removed by carefully using an approved chemical cleaner and a cotton swab, then blowing dry with compressed air