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P2048 OBD-II Trouble Code: Reductant Injector Circuit Low Bank 1 Unit 1

diagnostic check engine light

P2048 code definition

The P2048 code is a generic powertrain code related to the exhaust system. In this case, it means that the reductant injector circuit located on bank 1 unit 1 of the exhaust has a low circuit.

Codes related to the P2048 include:

What the P2048 code means

A code P2048 will be stored when the engine control module (ECM) finds a fault or malfunction in the reductant injector air pressure sensor circuit. In order to reduce noxious gases expelled from the diesel particulate filter (DPF) in a diesel engine or catalytic converter in a gasoline engine, the reductant injector is used. The bank of the engine that contains the number one cylinder is bank 1, and unit 1 is the pre-diesel particulate filter or upstream catalytic converter sensor.

Most often used on a diesel vehicle, reductant injection systems can be found on all types of vehicle exhaust systems. They utilize water, a chemical agent, or a combination of all three items in order to reduce exhaust emissions through reducing temperature and/or pressure in the DPF or catalytic converter. If a vehicle’s ECM notes an exhaust temperature, pressure, and/or noxious gas concentration higher than allowed preset parameters, the reductant injector will be activated and the reductant compound is sprayed into the DPF or catalytic converter.

As a vehicle’s exhaust gas temperature goes up, the level of resistance in the sensor decreases, which allows a feedback voltage signal to the ECM to also go up. With the engine off, as the exhaust temperature goes back down, circuit resistance increases and the feedback voltage signal to the PCM also goes down.The voltage variations are seen by the ECM as the exhaust gas temperature and it will adjust ignition timing or the air/fuel ratio to needed levels. If the downstream levels fail to display significant reduction, a code will be stored and a service engine soon lamp may be illuminated

What causes the P2048 code?

Several problems may cause a P2048 code including:

  • Damaged, corroded, loose, or defective electrical wiring and related terminals and connectors
  • Damaged or defective exhaust gas temperature sensor
  • Short to ground in exhaust gas temperature sensor
  • Exhaust leak upstream from exhaust gas temperature sensor

What are the symptoms of the P2048 code?

Symptoms of a P2048 code may include:

  • Check engine or warning light may illuminate
  • Vehicle may emit dark smoke when accelerating
  • May be no symptoms aside from a stored P2048 code

How does a mechanic diagnose the P2048 code?

A mechanic may use several methods to diagnose a P2048 trouble code, including:

  • Utilize an OBD-II scanner to check for a stored P2048 trouble code
  • Visually inspect all wiring and related electrical components for signs of wear, corrosion, or damage
  • Visually inspect the exhaust system for signs of leaks
  • Visually inspect the exhaust gas temperature/pressure sensors and circuitry
  • Disconnect exhaust gas temperature sensor connector and sensor
  • Check resistance of exhaust gas temperature/pressure sensor, which should read around 150 ohms
  • Perform a continuity test on sensor wire

Common mistakes when diagnosing the P2048 code

There are times that theoxygen sensor may be identified as the fault, and replaced in error. It is recommended to thoroughly diagnose and repair the exhaust gas temperature/pressure sensor when a code P2048 is stored.

How serious is the P2048 code?

Because a vehicle’s safe and driving operation most likely will be impacted and excessive emissions can be released due to faults that store a P2048 code, this code is considered a potentially serious code. When this code appears, it is recommended to immediately take your vehicle to your local service center or mechanic for repair and diagnosis.

What repairs can fix the P2048 code?

Several repairs can fix a P2048 trouble code and include:

Additional information related to a P2048 code

A P2048 code may be stored due to the installation of an aftermarket exhaust system that is causing backpressure on the system. It is recommended to check local, state, and federal laws before updating your vehicle’s exhaust system with aftermarket materials.

Need help with a P2048 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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