Technical Description of OBD-II Trouble Code
The circuit for the Diesel Intake Air Flow Position Sensor is registering a high reading.
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain/engine code that is applicable to all diesel OBD-II equipped engines. However, it is more commonly found in certain Chevy, Dodge, Ford, and GMC trucks.
While the code is generic, the specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
The Diesel Intake Air Flow Position Sensor (DIAFPS) is typically located on the throttle body, which is mounted to the intake manifold or in a tube within the intake air stream. This sensor 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 EGR system is activated, the PCM should detect a change in airflow. If not, there may be an issue with the EGR system or the DIAFPS (also known as a MAF sensor). This code is triggered when the input does not match the normal engine operating conditions stored in the PCM’s memory, even for a brief moment.
The code P02E9 Diesel Intake Air Flow Position Sensor Circuit High is set when the voltage at the sensor remains above a certain level (usually over 4.8V) for an extended period. This code is typically associated with an electrical circuit problem.
The troubleshooting steps may vary depending on the manufacturer, type of DIAFPS motor/control, and wire colors.
What is the severity of this DTC?
In all cases, the severity of this DTC is considered to be not severe. Since it is an electrical failure, the PCM can compensate adequately for it.
What are some of the symptoms of the code?
Some symptoms of a P02E9 trouble code may include:
What are some of the common causes of the code?
Some possible causes for this P02E9 code may include:
What are some P02E9 troubleshooting steps?
A good starting point is to check for technical service bulletins (TSB) for your vehicle. There 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. It is usually bolted to the throttle body mounted to the intake manifold or in a tube within the intake air stream. Once located, visually inspect the connector and wiring for any signs of damage such as scraping, rubbing, bare wires, burn spots, or melted plastic. Disconnect the connector and carefully examine the terminals inside for any signs of burning or corrosion. If necessary, clean the terminals using electrical contact cleaner and a plastic bristle brush. After cleaning, apply electrical grease to ensure proper contact.
If you have a scan tool, clear the diagnostic trouble codes from memory and check if the P02E9 code returns. If it does not, then the issue was most likely related to the connections.
If the P02E9 code does return, further testing of the DIAFPS sensor and its associated circuits is necessary. With the Key Off, disconnect the electrical connector at the DIAFPS sensor. Connect a Digital Voltmeter’s black lead to the ground terminal at the DIAFPS sensor wiring harness connector, and connect the red lead to the signal terminal. Turn the Key On Engine Off and check the voltmeter reading against the manufacturer’s specifications. It should read 5 volts. If not, repair the signal or ground wire, or replace the PCM.
If the previous test passed and you continue to receive a P02E9 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 unsure, seek assistance from a trained automotive diagnostician. Remember that PCMs must be programmed or calibrated to the vehicle for correct installation.
