P2055: Reductant Injection Valve Circuit High (Bank 1 Unit 2)

P2055 is set when the control line of DEF injector 2 on Bank 1 is shorted to battery positive. In GM's 2025 diesel table (25OBDG04B) the power stage of metering valve 2 reports the short; with more than 11 V and 30 faulty readings out of 60 the ECM stores a Type A fault, just as P2049 does for valve 1. Deutz assigns failure type 12 (voltage above normal or short to the high source) to metering unit 2 on EMR5 engines. On Ford's 2023 diesels the code instead describes a coil resistance more than 2 ohm above expectation, which hints at corroded terminals or an ageing winding. Whatever the platform, a driver that detects overvoltage is disabled, so the second dosing point delivers nothing until the circuit is repaired.

Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.

Symptoms

• MIL on
• Second dosing point inactive
• Increased NOx emissions

Most likely causes

• Control line of injector 2 shorted to battery positive
• Coil resistance too high, corroded terminals (Ford definition)
• Defective output stage for valve 2

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the AdBlue/DEF level and quality, and do not add additives or water
2. Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
3. Look for white crystals around the injector and the tank
4. Check connectors and heaters with the scanner
5. Run the dosing test available on your diagnostic tool
6. Replace parts only when the test points to that component

Good to know

• Repair difficulty: medium
• It can trigger limp mode.
• It affects emissions.

What each character of P2055 means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 0: Subsystem depends on the code range
• 55: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2055?

Deal with it soon. If the instrument cluster shows a countdown, the car may not restart once it reaches zero.

What causes code P2055?

The most common causes are: control line of injector 2 shorted to battery positive; coil resistance too high, corroded terminals (Ford definition); defective output stage for valve 2.

Related codes

• P2053Reductant Injection Valve Circuit/Open (Bank 1 Unit 2)
• P2054Reductant Injection Valve Circuit Low (Bank 1 Unit 2)
• P2049Reductant Injection Valve Circuit High (Bank 1 Unit 1)
• P2058Reductant Injection Valve Circuit High (Bank 2 Unit 2)

Sources

• gsi.ext.gm.com: 25OBDG04B
• serdia.deutz.com: DTCList MD1 DE EN
• fordservicecontent.com: obd summary diesel 2023

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.