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P02E6 Diesel Intake Air Flow Position Sensor Circuit

OBD-II Trouble Code Technical Description

Article by
Randy Worner
ASE Certified Master Technician

Diesel Intake Air Flow Position Sensor Circuit

What does that mean?

This generic powertrain/engine diagnostic trouble code (DTC) can typically apply to all diesel OBD-II equipped engines, but shows up more often in certain Chevy, Dodge, Ford and GMC trucks.

Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.

The Diesel Intake Air Flow Position Sensor (DIAFPS) is usually bolted to the throttle body mounted to the intake manifold or in a tube in the intake air stream. The DIAFPS sensor converts the incoming airflow volume 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 versus how much is entering through the exhaust system via the Exhaust Gas Recirculation System, or EGR System. When the EGR system is activated, the PCM should note a change in airflow. If not, then there may be something wrong with the EGR system, or there may be something wrong with the DIAFPS, also known as a MAF sensor. This code is set if this input does not match normal engine operating conditions stored in the PCM’s memory, even for a second, as these diagnostic trouble codes demonstrate. It also looks at the voltage signal from the DIAFPS to determine if it is correct at initial Key On.

The code P02E6 Diesel Intake Air Flow Position Sensor Circuit indicates a general malfunction within the diesel intake air flow position sensor circuit. It could have been set because of mechanical (physical damage to the sensor itself, thereby causing an electrical fault) or electrical (DIAFPS sensor circuit) issues. These cannot be overlooked in the troubleshooting stage, especially when dealing with an intermittent problem.

Troubleshooting steps may vary depending upon manufacturer, type of DIAFCS motor/control and wire colors.

What is the severity of this DTC?

Severity in all cases will be not severe. Since they are electrical failures, the PCM can compensate adequately for them.

What are some of the symptoms of the code?

Symptoms of a P02E6 trouble code may include:

What are some of the common causes of the code?

Causes for this P02E6 code may include:

What are some P02E6 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 put out by the manufacturer and 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 mounted to the intake manifold or in a tube in the intake air stream. Once located, visually inspect the connector and wiring. Look for scraping, rubbing, bare wires, burn spots or melted plastic. Pull the connector apart and carefully inspect the terminals (the metal parts) inside the connector. See if they look burned or have a green tint indicating corrosion. Use electrical contact cleaner and a plastic bristle brush if cleaning of the terminals is needed. Let dry and apply electrical grease where the terminals contact.

If you have a scan tool, clear the diagnostic trouble codes from memory, and see if P02E6 code returns. If it does not, then the connections were most likely your problem.

If the P02E6 code does return, we 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. Check manufacturer’s specifications; 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 P02E6, this would most likely indicate a failed DIAFCS sensor, although a failed PCM could not be ruled out until the DIAFCS sensor had been replaced. If unsure, seek assistance from a trained automotive diagnostician. PCMs must be programmed, or calibrated to the vehicle to be installed correctly.

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