What it means
Reductant Injection Valve Circuit Range/Performance (Bank 1 Unit 1): the signal is implausible or outside the valid 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 reductant injection valve doses DEF into the exhaust so the SCR system can reduce NOx emissions. The control module monitors the valve's electrical response and whether it behaves as expected during dosing. P202E sets when the Bank 1 Unit 1 valve circuit response is outside its expected range or performance.
Common causes
Most likely first.
- Reductant injection valve fault
- Open or damaged wiring
- Poor electrical connection
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
- Record freeze-frame data and check live reductant dosing commands and related SCR codes to see when the Bank 1 Unit 1 valve response became implausible.
- Locate the Bank 1 Unit 1 reductant valve using vehicle service information, then inspect its connector and nearby harness for corrosion, heat damage, loose pins, or chafing.
- Check DEF lines and the valve mounting area for crystals or leaks that could interfere with valve operation.
- With the valve disconnected as specified by service information, test its wiring for continuity, shorts, and poor connections between the valve and control module.
- Compare valve electrical response and commanded dosing using the manufacturer's diagnostic procedure to distinguish a valve fault from a harness or control issue.
- After repair, clear the code and confirm that commanded dosing and valve feedback are plausible during the appropriate system test.
Common fixes
- Clean and secure a loose or corroded Bank 1 Unit 1 valve connector.
- Repair damaged wiring or terminals in the valve circuit.
- Replace the Bank 1 Unit 1 reductant injection valve if it fails the specified electrical or operating test.
- Repair a leaking or damaged valve connection if DEF residue is affecting the assembly.
Can I keep driving?
The vehicle may remain drivable, but emissions control can be impaired and a NOx warning or DEF countdown may appear. Avoid ignoring warnings or delaying repair, since some vehicles can eventually restrict starting.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.