P2055 OBD-II Trouble Code: Reductant Injector Circuit High Bank 1 Unit 2

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P2055 code

P2055 is a diagnostic trouble code (DTC) for "Reductant Injector Circuit High Bank 1 Unit 2". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P2055 DIAGNOSTIC Get a fair and transparent estimate upfront

P2055 code definition

When the Powertrain Control Module (PCM) detects a variation in the voltage coming from the reductant injector air pressure sensor circuit, a P2055 trouble code is stored. Used most often in diesel engines, the reductant injector air pressure sensor circuit is also found in gasoline and turbocharged engines. A reductant injector system helps cool the exhaust, making it easier for the catalytic converter to reduce the emissions commonly found in the vehicle exhaust. Some other related codes include P2047, P2048, P2049, P2050, P2051, P2052, P2053, P2054, P2056, P2057, and P2058.

What the P2055 code means

A P0255 trouble code means that the reductant injector air pressure sensor has detected a malfunction. This, in turn, causes a code storage on the PCM and the Check Engine Light to come on. Bank 1 is the bank that contains the number one cylinder in the engine, while unit 2 is one of two things – the post diesel particulate filter, also known as the catalytic converter, and the downstream sensor. Keep in mind that multiple drive cycles might be required in some model of vehicles before the Check Engine Light is lit, though a P0255 trouble code is stored upon the initial incident.

What causes the P2055 code?

A P0255 trouble code is most often caused by loose or damaged wiring or connectors. Some other causes include a faulty sensor, a decrease in back pressure, a severe upstream exhaust leak, and the exhaust gas temperature sensor being shorted, either internally or to the ground.

What are the symptoms of the P2055 code?

The only visible sign of a P0255 trouble code is excessive black smoke emanating from the vehicle's tailpipe upon acceleration.

How does a mechanic diagnose the P2055 code?

Diagnosing a P0255 trouble code requires a mechanic to use an infrared thermometer with a laser pointer, a digital volt/ohmmeter, and an OBD-II scanner or code reader. In addition to the proper tools, a mechanic should perform the following steps when diagnosing this code:

  • Inspect all wiring and connectors for looseness and damage. This includes burnt, corroded, or otherwise damaged wiring and connectors.

  • Download any freeze frame data or stored codes by connecting the OBD-II scanner to the diagnostic connector.

  • Visually examine the exhaust gas temperature/pressure sensor and any associated circuitry.

  • Check the resistance of the exhaust gas temperature/pressure sensor using a digital volt/ohmmeter.

  • If the resistance of the exhaust gas temperature/pressure sensor checks out, leave the volt/ohmmeter attached and heat the sensor with a heat gun, observing the resistance level of the sensor as the temperature increases, making sure it decreases smoothly.

  • Use the volt/ohmmeter to check the PCM for continuity.

  • Clear the code and test the system to see if the code returns.

Common mistakes when diagnosing the P2055 code

A common mistake made by a mechanic diagnosing a P0255 trouble code is to mistake the oxygen sensor for the exhaust gas temperature sensor. Also, another misdiagnosis is for the mechanic to mistakenly think the oxygen sensor is somehow integrated into the exhaust gas temperature sensor, so they replace the oxygen sensor. Replacement of the oxygen sensor will not fix the problem in both of these cases, and the a mechanic can expect the code to return.

How serious is the P2055 code?

A fault with the exhaust gas temperature/pressure sensor within the reluctant injection system can lead to higher vehicle emissions.

What repairs can fix the P2055 code?

Repairing a P0255 trouble code can be a multistep process and often requires the mechanic to perform the following:

  • Repair any damaged wiring, connectors, or components.

  • Replace the exhaust gas temperature/pressure sensor if found to be at fault.

  • Replace and reprogram the PCM if faulty.

  • As a last resort, the mechanic can also install an inline resistor, of at least 2.5 ohms between the signal and ground wires of the PCM, and leaving the exhaust gas temperature sensor disconnected.

Additional comments for consideration regarding the P2055 code

Before removing any parts related to a vehicle's emission system, the mechanic should check local, state, and federal laws to make sure they stay within compliance.

Need help with a P2055 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.

trouble codes
Check Engine Light
P2055

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P2055 code.

SCHEDULE P2055 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

5,606

Rating Summary
5,180
205
50
34
137
5,180
205
50
34
137

James

40 years of experience
34 reviews
James
40 years of experience
Ford F-150 - Check Engine Light is on - Chagrin Falls, Ohio
Jim was great! Arrived on time, quickly diagnosed the problem and recommended further work. Very helpful, I’ll use Jim again and recommend to family and friends.

Roberto

11 years of experience
137 reviews
Roberto
11 years of experience
Nissan Titan - Check Engine Light is on - Spring, Texas
Roberto was very thorough with his explanation of repairs needed. I will contact your mechanic for future repairs.

Matthew

32 years of experience
839 reviews
Matthew
32 years of experience
Kia Optima - Check Engine Light is on - Yorktown, Virginia
Matthew Lerman was God Sent, and thank God for Your Mechanic,, you have my Vote Looking , Looking forward for more Business. Very Honest Guy

Robert

20 years of experience
38 reviews
Robert
20 years of experience
Honda Accord - Check Engine Light is on - Brentwood, California
He came earlier than on time and got the job done faster than I seen anyone else have . Solid honest hard working dude.


More related articles

B1330 OBD-II Trouble Code: Passenger Door Ajar Circuit Short to Ground
B1330 means there is an error with the passenger door ajar circuit, likely due to a malfunctioning passenger door ajar switch or a door latch jam.
P0295 OBD-II Trouble Code: Cylinder 12 Injector Circuit High
P0295 P0295 Code Definition Cylinder 12 Injector Circuit High What the P0295 code means The P0295 trouble code means that the Engine Control Module (ECM) detects resistance in the cylinder 12 fuel injector circuit as falling outside the normal range...
P0590 OBD-II Trouble Code: Cruise Control Multi-Function Input “B” Circuit Stuck
P0590 means an electrical issue with the cruise control multi-function input B circuit, commonly caused by a malfunctioning cruise control switch.

Related questions

Computer Problem? 2014 Honda Civic

Hello - I would first go to an auto parts store and have them check for any problem codes (this is normally free), whether the Check Engine light is on or not. Depending on the results of the code scan,...

P0420 code comes back repeatedly, emissions readiness issue. Takes about a week for Check Engine Light to come back on.

If this is the only code that keeps coming up, and the data stream on the oxygen sensors are reacting correctly, the only real other thing left would be the convertor. If there was a wiring issue, or a sensor...

Computer reads an issue with the oxygen sensor on a Subaru Forester 1999 2.0 Turbo. What is the problem?

Your 1999 Subaru Forester has pre and post catalytic converter oxygen sensors. The pre-converter sensor optimizes fuel trim while the post converter sensor monitors the efficiency of the catalytic converter. A failing pre-converter sensor will degrade vehicle MPG performance. Although...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com