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P2041 OBD-II Trouble Code: Reductant Injector Air Press Sensor Circuit Intermittent

diagnostic check engine light

P2041 code definition

Found in both diesel and gasoline engines, the reductant injector helps reduce the noxious fumes expelled through the particulate filter in a diesel engine and the catalytic converter in gasoline fueled engines. When a malfunction is detected in the reductant injector air pressure sensor circuit by the Powertrain Control Module (PCM), a P2041 trouble code is stored.

Related trouble codes:

What the P2041 code means

A P2041 trouble code means that the PCM has received a variation in the system voltage from the reductant injector air pressure sensor that exceeds manufacturer's limitations. For some vehicle models, multiple drive cycles are needed before the Check Engine light illuminates.

What causes the P2041 code?

Causes of a P2041 trouble code include:

  • Loose, broken, corroded, or other damage to wiring connectors and other components

  • Faulty reductant injector air pressure sensor

  • Severe exhaust leak upstream in the system from the exhaust temperature sensor

  • Decrease in back pressure caused by the installation of an aftermarket off road exhaust system

What are the symptoms of the P2041 code?

The only symptom of a P2041 trouble code is excessive black smoke upon acceleration. Other than this, the only other signs of a P2041 trouble code is the lit Check Engine light and the stored trouble code.

How does a mechanic diagnose the P2041 code?

To successfully diagnose a P2041 trouble code, the mechanic needs an advanced scanner or code reader, a digital volt/ohmmeter, a heat gun, and an infrared thermometer with a laser pointer. In addition to the proper equipment, a mechanic needs to perform the following:

  • Visually inspect all related wiring, connectors, and components for any looseness, fault, or corrosion.
  • After repairing the wiring, connectors, or components, clear the trouble code and test the system.
  • If the code returns, connect the scanner and download any stored trouble codes and flash frame data.
  • The mechanic should also inspect the exhaust gas temperature sensor and the surrounding circuitry.
  • The mechanic should pay particular attention to the wiring and connectors near any hot exhaust components. The mechanic is looking for any heat damage cause by the hot exhaust parts.
  • After replacing any damaged parts, clear the code and retest the system.
  • If the code returns, the mechanic should check the resistance of the exhaust gas temperature sensor using the digital volt/ohmmeter.
  • If the sensor falls within specifications, leave the volt/ohmmeter leads attached and heat the exhaust gas temperature sensor using a heat gun.
  • If everything still checks out, turn the ignition to the ON position and test for reference voltage and a ground signal at the exhaust gas temperature sensor electrical connector.
  • If low voltage is detected, disconnect the PCM and check for continuity on the wire leading to the exhaust gas temperature sensor.
  • Continuity on this circuit might indicate that the PCM is at fault. In this instance, check the PCM for continuity and resistance.
  • Clear the trouble code and clear it before retesting the system to see if the code returns.

Common mistakes when diagnosing the P2041 code

Mechanics most often mistake the oxygen sensor for the exhaust gas temperature sensor. Replacing the oxygen sensor does not fix the problem with the trouble code soon returning.

How serious is the P2041 code?

Other than excessive black smoke from the exhaust pipe, a vehicle owner does not have to worry about any serious issues from the storage of a P2041 trouble code.

What repairs can fix the P2041 code?

Repairing a P2041 trouble code can include:

  • Replacing any faulty or damaged wiring, connectors, or components
  • Exhaust gas temperature sensor replacement
  • Replacing damaged wiring, connectors, or components caused by hot exhaust parts
  • PCM replacement and reprogramming

Additional comments for consideration regarding the P0100 code

If the vehicle owner has installed a high-performance exhaust system on the vehicle, the lack of back pressure, due to no catalytic converter, can cause the storage of a P2041 trouble code. To fix this problem, the mechanic can install an inline resistor, of at least 2.5 ohms, between the signal and ground wires. In addition, the mechanic should leave the exhaust gas temperature sensor disconnected. This causes the PCM to read the sensor resistance and pass it without storing a trouble code. Before removing any emission related components, the mechanic should check any local, state, or federal laws concerning this type of modification.

Need help with a P2041 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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