Mass Air Flow (MAF) Circuit Range/Performance Problem


This code indicates that unacceptable MAF voltage has been detected for a period exceeding four-seconds continually.

Code Set Parameters

An unacceptable MAF voltage reading 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 a service engine soon light.

Common Causes

Common causes of this code are a disconnected plug at the MAF sensor, moisture or debris that has contaminated the vane of the MAF, a faulty MAF, a cracked or broken air inlet pipe, clogged air filter element, or faulty PCM. PCM failures are rare.

Common Misdiagnosis

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


  • 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