HomeTrouble CodesP2053

P2053 — Reductant Injection Valve Circuitopen Bank 1 Unit 2

Manufacturer-specificPowertrain (engine & transmission)

OBD-II code P2053 indicates that the engine control module has detected an open circuit in the reductant injection valve for Bank 1 Unit 2. This means the electrical path to the diesel exhaust fluid (DEF) injector is incomplete, preventing the selective catalytic reduction (SCR) system from injecting DEF to reduce nitrogen oxide emissions.

Symptoms

What causes it — most likely first

1. Failed reductant injection valve

The DEF injector itself can fail internally, causing an open circuit that prevents operation and triggers the code.

2. Wiring harness issue

Corroded, chafed, or broken wires in the reductant injection valve circuit can create an open electrical condition.

3. Poor electrical connection

Corrosion or loose pins in the injector connector can interrupt the electrical signal to the valve.

4. Blown fuse or open relay

A blown fuse in the DEF system power circuit can cut power to the injection valve, resulting in an open circuit code.

5. Failed Engine Control Module (PCM/ECM)

An internal failure in the control module driver circuit is extremely rare but could theoretically cause this code.

How it's diagnosed

  1. Scan for additional codes and document freeze frame data to understand the conditions when P2053 set.
  2. Visually inspect the wiring harness and connector at the Bank 1 Unit 2 reductant injection valve for damage, corrosion, or loose pins.
  3. Check the relevant fuses and relays for the DEF injection system and verify power is reaching the injector circuit.
  4. Test for battery voltage and ground at the reductant injection valve connector to confirm the electrical path is complete.
  5. Measure the resistance of the reductant injection valve to check for an internal open, comparing to manufacturer specifications.
  6. If all wiring, connectors, and the injector itself test normal, check the PCM/ECM connector and wiring for issues before considering module failure.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

Can I drive my vehicle with a P2053 code?

It is not recommended. The vehicle may enter a reduced power mode to protect the emissions system, and driving without proper DEF injection can result in a no-start condition after repeated attempts.

Does P2053 mean I need to replace my PCM/ECM?

No, replacing the PCM/ECM is almost never the correct fix for this code. Drivers are frequently misdiagnosed with a bad module, but the cause is overwhelmingly a failed reductant injection valve, wiring issue, or poor connection. Control module failure is exceptionally rare for this code.

Is the reductant injection valve the same as the DEF injector?

Yes, the reductant injection valve is the component that sprays diesel exhaust fluid (DEF) into the exhaust stream. It is commonly referred to as the DEF injector.

Can a bad DEF tank heater cause a P2053 code?

No, a DEF tank heater issue will typically set a specific code related to the heater circuit. P2053 specifically points to an open circuit in the Bank 1 Unit 2 injection valve itself.