P2052

Code

Generic P — Powertrain

Reductant Injection Valve Circuit High Bank 2 Unit 1

Brand: Generic

Type: P — Powertrain

Views: UK: 25 EN: 45 RU: 33

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Causes

Open or shorted wiring in the reductant injection valve control circuit (Bank 2, Unit 1)
Corroded, bent or loose connector terminals at the valve or harness
Failed reductant injection valve (stuck open, internal open coil, or internal short)
Blown fuse or failed relay supplying valve power or ECM
Poor or missing ground for ECM or related control circuits
ECM/PCM driver transistor failure (output stage stuck high)

Symptoms

Malfunction Indicator Lamp (MIL) or Check Engine Light illuminated
Reduced or disabled SCR/reductant dosing; possible elevated NOx readings
Emissions test failure or warning messages for aftertreatment
Possible limp-mode or emissions-related derate depending on vehicle
No obvious change in engine running in some cases (electrical fault only)

What to check

Confirm freeze-frame data and related refrigerant/reductant system codes with a scan tool
Visually inspect harness and connector at the reductant injection valve for corrosion, damage, or loose pins
Check fuses and relays related to reductant system power and ECM power/grounds
Backprobe the valve connector and monitor voltage while commanding the valve ON/OFF with a scan tool
Measure coil resistance of the reductant valve with the harness disconnected
Perform continuity checks from the ECM control pin to the valve connector and for shorts to battery or ground

Signal parameters

Expected control circuit behavior (general): Off/open command ≈ battery voltage (~11–13.5 V), Valve ON (ECM grounds driver) ≈ ~0–2 V when actively switched
Typical coil resistance (dependent on valve design): commonly in the range ~5–30 ohms (check vehicle-specific spec)
Current draw when energized: typically several hundred mA to a few amps (varies by valve)
Fault indication: ECU detects voltage above expected (high) on control circuit when valve should be grounded/active

Diagnostic algorithm

Use a scan tool to confirm P2052 and review any other stored/emission codes and freeze-frame data. Clear codes and see if P2052 returns.
Visually inspect the reductant valve connector, wiring harness along its routing (look for chafing, pinched areas, corrosion, rodent damage) and secure grounds for ECM and related circuits.
With harness connected, backprobe the valve control pin. With the scan tool, command the valve ON and OFF while observing voltage: when commanded ON the control circuit should be pulled low (near 0–2 V); if it remains high (~battery voltage) the circuit is stuck high.
Disconnect the valve; measure the valve coil resistance with an ohmmeter and compare to vehicle specification. If open or out of spec, replace the valve.
With the valve disconnected, check continuity between the control wire and ECM control pin. Check for short to battery: measure resistance/voltage between control wire and battery positive. Check for short to ground as well.
Verify power and ground circuits: check fuses and relays that supply ECM and reductant circuit, and test ECM ground integrity.
If wiring and valve check good, consider substituting a known-good valve or using a bench test to energize the valve to confirm operation.
If wiring and valve are good and the fault persists, test or replace the ECM output driver only after confirming all other possibilities (follow vehicle-specific service manual precautions).
After repairs, clear codes and perform re-check drive cycle/functional test of reductant dosing to confirm the fault does not return.