Fault code P02E8 is called “Diesel Intake Air Flow Position Sensor Circuit Low” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P02E8
When the PCM detects a problem with the intake air flow position sensor or its circuit, it sets code P02E8. In this case, the code is set when an abnormally low voltage is detected in the intake air flow position sensor control circuit.
The Diesel Inlet Air Flow Sensor (DIAFPS) is normally bolted to the throttle body. It converts the volume of incoming airflow into an electrical signal for the Powertrain Control Module (PCM).
The PCM receives this voltage signal to determine how much clean, filtered air is entering the engine. And also how much is coming in through the exhaust gas recirculation system, or EGR system.
When the EGR system is activated, the PCM should notice a change in airflow. If it doesn’t, there may be something wrong with the EGR system, or with the inlet airflow position sensor.
The amount of air flowing through the intake is controlled by the intake air valve on the throttle body. The intake air position sensor tells the engine control module (PCM) the position of the diesel engine intake air flow control valve.
Diagnostic code P02E8 indicates a low signal level in the diesel engine intake air flow position sensor circuit. It is set when the sensor voltage remains below the set level (normally less than 0.3 V) for too long a period of time.
Symptoms of vehicle malfunctions
The main signal that an error P02E8 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will light up (the code will be recorded in the memory as a malfunction).
- The idle speed may be low.
- Exhaust gas recirculation system does not work (EGR).
- Failure of regeneration of particulate filter to burn off soot deposits.
- Reduced engine power output.
- Increased fuel consumption.
The P02E8 error is not considered serious, but as with any problem, it is recommended that it be resolved. In most cases, the PCM can compensate for an electrical problem if there are no other sensors in this reference circuit.
Factors that can cause this error code
The error code P02E8 can mean that one or more of the following problems have occurred:
- Defective diesel engine intake air flow position sensor.
- Damaged or worn sensor connector.
- Damaged, burned, shorted, disconnected, or corroded wiring.
- Sometimes faulty PCM module is the cause.
How to fix or reset OBD-2 code P02E8
Some suggested steps for troubleshooting and fix the error code P02E8:
- Connect an OBD-II scanner to the vehicle’s diagnostic connector and read all stored data and error codes.
- Clear the error codes from the computer memory and test-drive the vehicle to see if code P02E8 appears again.
- If the code appears again, check the wiring and associated connectors leading to the diesel intake air flow position sensor. Make sure they are not broken or frayed. Repair or replace if necessary.
- Inspect and test the diesel engine intake air flow position sensor, and replace if it is defective.
- If faulty PCM is the cause, replace or reprogram it.
Diagnose and repair of problems
Inspect visible damage to the sensor, wiring, and connectors. Then start the diagnostic procedure with the scan tool. To determine if error P02E8 is the only error, if not, it may be worth investigating the other fault codes first.
If no problems are found with damaged or corroded connectors, perform a thorough inspection of all associated wiring. Repair or replace damaged wiring as necessary.
Check wiring and intake air flow position sensor
If no visible wiring damage is found, prepare to perform reference voltage, ground, resistance, and continuity tests. Be sure to disconnect the sensor from the wiring harness so as not to damage the PCM and avoid a short circuit.
If code P02E8 returns, check the diesel engine intake air flow position sensor and related circuits. With the engine off, disconnect the sensor electrical connector.
Connect the black wire of the digital voltmeter to the ground terminal on the intake air flow sensor wiring harness connector. Connect the red wire of the digital voltmeter to the signal terminal of the sensor wiring harness connector.
Check the manufacturer’s specifications, the voltmeter should read 5 volts. If it does not, pay attention and repair the signal or ground wire, or replace the PCM.
If the previous check was successful, but the P02E8 error remains, the sensor itself is most likely faulty. Although a faulty PCM cannot be ruled out before replacing the sensor either.
If you are unsure of the action you are taking, get help from a qualified technician. For proper installation, the PCM must be programmed or calibrated for the specific vehicle.
On which vehicles does this problem occur most frequently
Fault code P02E8 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Chevrolet
- Dodge
- Ford (Kuga, Mondeo, Transit)
- GMC
- Land Rover (Freelander)
- Volvo
Fault code P02E8 can sometimes be found with other errors. The most common are the following: P02E6, P02E7, P02E9, P02EA, P02FA.
