Technical Description of OBD-II Trouble Code
The performance of the Diesel Intake Air Flow Position Sensor (DIAFPS) is not meeting the minimum or maximum requirements.
What does that mean?
This diagnostic trouble code (DTC) is a generic code that can apply to all diesel OBD-II equipped engines. However, it is more commonly found in certain Chevy, Dodge, Ford, and GMC trucks.
The exact repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
The DIAFPS sensor is typically located on the throttle body attached to the intake manifold or in a tube in the intake air stream. It converts the incoming airflow volume into an electrical signal for the Powertrain Control Module (PCM).
The PCM uses this voltage signal to determine the amount of clean, filtered air entering the engine compared to the amount entering through the exhaust system via the Exhaust Gas Recirculation System (EGR System). If the PCM does not detect a change in airflow when the EGR system is activated, there may be an issue with the EGR system or the DIAFPS sensor (also known as a MAF sensor). This code is set when the input does not match the normal engine operating conditions stored in the PCM’s memory, even for a brief moment.
The code P02FA indicates a problem with the minimum or maximum stop performance in the diesel intake air flow position sensor circuit. This problem could be caused by mechanical damage to the sensor itself, resulting in an electrical fault, or by issues with the DIAFPS sensor circuit. It is important not to overlook these possibilities during the troubleshooting stage, especially when dealing with an intermittent problem.
The severity of this DTC is not severe in all cases. Since it is an electrical failure, the PCM can compensate adequately for it.
What are some of the symptoms of the code?
Symptoms of a P02FA trouble code may include:
What are some of the common causes of the code?
Causes for this P02FA code may include:
What are some P02FA troubleshooting steps?
A good starting point is always to check for technical service bulletins (TSB) for your vehicle. Your issue may be a known issue with a known fix provided by the manufacturer, which can save you time and money during diagnosis.
Next, locate the DIAFPS sensor on your vehicle. This sensor is usually bolted to the throttle body attached to the intake manifold or in a tube in the intake air stream. Once located, visually inspect the connector and wiring for any signs of damage. Look for scraping, rubbing, bare wires, burn spots, or melted plastic. Pull the connector apart and carefully inspect the terminals inside for any signs of burning or corrosion. Clean the terminals if necessary using electrical contact cleaner and a plastic bristle brush. Apply electrical grease to ensure proper contact.
If you have a scan tool, clear the diagnostic trouble codes from memory and see if the P02FA code returns. If it does not, then the issue was most likely related to the connections.
If the P02FA code does return, you will need to test the DIAFPS sensor and its associated circuits. With the Key Off, disconnect the electrical connector at the DIAFPS sensor. Connect a Digital Voltmeter black lead to the ground terminal at the DIAFPS sensor wiring harness connector. Connect the red lead of the Digital Voltmeter to the signal terminal at the DIAFPS sensor wiring harness connector. Turn Key On Engine Off and check the manufacturer’s specifications. The voltmeter should read 5 volts. If not, repair the signal or ground wire, or replace the PCM.
If the prior test passed and you continue to get a P02FA code, it is likely that the DIAFPS sensor has failed. However, a failed PCM cannot be ruled out until the DIAFPS sensor has been replaced. If you are unsure, seek assistance from a trained automotive diagnostician. PCMs must be programmed or calibrated to the vehicle for correct installation.
