P02EC Diesel intake airflow control system - high airflow detected

OBD-II DTC Datasheet

Diesel Intake Air Control System - High Air Consumption Detected

What does this mean?

This Generic Transmission / Engine Diagnostic Trouble Code (DTC) usually applies to all OBD-II equipped diesel engines, but is more common in some Chevy, Dodge, Ford and GMC trucks.

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

The Diesel Intake Air Control System (DIAFCS) is usually bolted to the intake manifold in the intake air flow. The DIAFCS system monitors the amount of incoming air flow by changing the signal to the engine controlled by the powertrain control module (PCM). The motor opens and closes the throttle valve, which regulates the air flow.

The PCM knows how much clean filtered air is entering the engine based on the diesel engine intake air position sensor, also known as the MAF sensor. When the airflow control system is activated, the PCM should notice a change in airflow. If not, there might be something wrong with the DIAFCS or something wrong with the MAF sensor. These codes are set if this input does not match the normal engine operating conditions stored in the PCM memory, even for a second, as these DTCs demonstrate. It also looks at the voltage signal from the DIAFCS to determine if it is correct when the key is initially turned on.

Code P02EC Diesel Intake Air Control System - High Air Consumption Detected is set when the diesel engine intake air control system detects high air consumption. This could be due to mechanical (physical damage to the control system itself, causing electrical failure) or electrical (DIAFCS motor circuit) problems. They should not be overlooked during the troubleshooting phase, especially when dealing with an intermittent problem.

Troubleshooting steps may vary depending on the manufacturer, type of engine / DIAFCS control unit and wire colors.

What is the severity of this DTC?

The severity in all cases will be low. If mechanical problems are the cause, then a typical failure is low idle. If it's an electrical failure, the PCM can compensate adequately.

What are some of the symptoms of the code?

Symptoms of a P02EC trouble code may include:

Fault indicator light is on
Only low idle speed possible
Flashing electronic throttle control symbol
No Regeneration of the particulate filter to burn off soot deposits (does not burn soot from the DPF catalytic converter) - complaint about a possible loss of power

What are some of the common causes for the code?

Reasons for this P02EC code may include:

Open in the signal circuit to the engine / control system DIAFCS - possible
Short to voltage in DIAFCS engine/control signal circuit - Possible
Short to ground in signal circuit to engine/DIAFCS control unit - possible
Faulty motor/DIAFCS control - likely
Failed PCM – Unlikely

What are some P02EC troubleshooting steps?

A good starting point is always checking the Technical Service Bulletins (TSB) for your vehicle. Your problem may be a known issue with a known manufacturer-released fix and could save you time and money while troubleshooting.

Then locate the DIAFCS engine / control system on your vehicle. This engine / regulator is usually bolted to the intake manifold in the intake air flow. Once found, visually inspect the connector and wiring. Look for scratches, scuffs, exposed wires, burn marks, or molten plastic. Disconnect the connector and carefully inspect the terminals (metal parts) inside the connector. See if they look burnt or have a green tint indicating corrosion. If you need to clean the terminals, use an electrical contact cleaner and a plastic bristle brush. Allow to dry and apply electrical grease where the terminals touch.

If a mechanical code has been set, use an air intake cleaner and a clean rag to wipe off carbon deposits behind the engine control throttle valve. Spray the cleaning agent onto a rag and wipe off any deposits with a rag. NEVER spray these deposits into the engine as they can cause poor performance, misfiring and insufficient intake cleaner, catalytic converter damage and possibly engine damage.

If you have a scan tool, clear the DTCs from memory and see if P02EC code returns. If this is not the case, then there is most likely a connection problem.

If the P02EC code does return, we will need to test the DIAFCS and its associated circuits. With the key OFF, disconnect the electrical connector at the engine / DIAFCS control unit. Connect the black lead from the DVM to the ground terminal on the DIAFCS engine / control harness connector. Connect the red lead from the DVM to the engine terminal on the DIAFCS harness connector. Turn on the engine, turn it off. Check manufacturer specifications; the voltmeter should read 12 volts. If not, repair the power or ground wire or replace the PCM. If you are unsure, check the manufacturer's specifications for full test procedures on your specific vehicle.

If the previous test passed and you continue to receive P02EC, it will most likely indicate a failed engine / DIAFCS control, although the failed PCM cannot be ruled out until the DIAFCS engine / control is replaced. If you are unsure, seek help from a qualified automotive diagnostician. To install correctly, the PCM must be programmed or calibrated for the vehicle.

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