P2052: Reductant Injection Valve Circuit High (Bank 2 Unit 1)

What it means

Reductant Injection Valve Circuit High (Bank 2 Unit 1): the signal voltage is above the expected range. This valve doses reductant (DEF/AdBlue) into the exhaust for SCR NOx reduction.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The Bank 2 Unit 1 reductant injection valve is an electrically operated injector that doses DEF/AdBlue into the exhaust. P2052 sets when its circuit signal is higher than expected, often because a wire is shorted to battery voltage or the circuit has an open that leaves the monitored signal high.

Common causes

Most likely first.

1. Short to B+
2. Connector pins corroded - high contact resistance
3. Supply wire pinched against B+ source

Symptoms

• Check engine light or NOx warning on
• AdBlue/DEF level or quality warning
• Possible no-start countdown after ignore period
• Failed emissions inspection (NOx)

How to diagnose it

1. Use freeze-frame data and a supported actuator test to confirm that the Bank 2 Unit 1 valve circuit is registering high.
2. Inspect the injector connector and harness for water, corrosion, backed-out pins, chafing, or contact with a power wire.
3. Test the valve control wire for a short to battery voltage and check for an open circuit using the vehicle wiring diagram and manufacturer's specification.
4. Check the valve winding and connector terminals to determine whether the injector itself contributes to the high reading.
5. If the wiring and valve pass, follow service information to test the control module driver before replacing it.
6. After repair, confirm that the Bank 2 Unit 1 circuit responds normally to a commanded dosing test.

Common fixes

• Repair connector damage, loose pins, or corrosion at the Bank 2 Unit 1 valve.
• Repair a control wire shorted to battery voltage or an open in the circuit.
• Replace the injector if its winding fails the specified electrical test.
• Repair a confirmed module driver fault and verify circuit response.

Can I keep driving?

If the vehicle is running normally, keep driving limited and arrange repair soon; the Bank 2 Unit 1 injector may not dose correctly, increasing NOx emissions. Continued operation can bring an SCR warning or a no-start countdown.