P2202 NOx sensor circuit low (bank 1)
P2202 comes back because a low NOx sensor signal is usually down to a wiring short or a failed sensor, and neither goes away with a reset. We test the circuit at your home, yard or depot and tell you which it is.
Why P2202 comes back after clearing
The official wording is NOx sensor circuit low (bank 1). The sensor's signal is sitting below the lowest figure the ECU will accept, which points to an electrical fault in the sensor, its module or the wiring.
The ECU checks that signal throughout every journey. Clear the code and the same low reading is picked up again almost immediately, often with the AdBlue countdown carrying on.
The usual causes behind P2202
| Cause | How it's checked |
|---|---|
| Wire shorted to earth between the sensor module and ECU | Circuit tests along the loom |
| Failed NOx sensor or its attached module | Module data and sensor status on live data |
| Corroded pins in the connector | Connector inspection |
| Supply fault to the sensor module | Supply and earth voltage checks |
Symptoms
- An emissions or AdBlue warning that returns after every reset
- A countdown message telling you the engine won't restart soon
- No obvious change in performance
Using the vehicle with P2202 showing
The vehicle usually runs normally, but without a working NOx sensor the countdown keeps going on many vans and cars. Get it diagnosed before the figure gets low.
Vans and fleets with P2202
A countdown running down on a working van is a problem waiting to happen. We test NOx sensor circuits on vans at your yard or depot between jobs, and businesses using us regularly can open a trade account.
How we stop P2202 coming back
NOx sensor circuit test, £100 + VAT
We check the sensor module, wiring and supply and tell you which part has failed, so the dealer or SCR specialist fixes the right thing. We don't carry out AdBlue or SCR repairs ourselves.
Reviews
Why does P2202 come back after it's been cleared?
The low signal is still there, and the ECU monitors it constantly, so the code is logged again within minutes.
Can a remap cause P2202?
No. P2202 is an electrical fault in the sensor circuit, which a properly set-up remap doesn't touch.
Can another fault set off P2202?
A supply fault shared with other modules can cause it, and codes such as P2200 often appear at the same time.
Can you check P2202 on our vans at the depot?
Yes. We'll test each affected van on site and tell you which need a sensor and which need wiring work.
What should I tell you when I book for P2202?
The registration, the full code, the countdown figure and any other warnings showing.
Is an AdBlue delete an option for a van on the road?
No. AdBlue deletes are only for vehicles used off-road or for export, and Is AdBlue delete legal? covers why.
Stop P2202 coming back
Book a fault check and we'll test the NOx sensor circuit at home, at work or at the depot.
More fault codes explained
Eccles, Manchester M30 0SF