P2202

Sensor Circuit Low Bank 1

P2202 is a generic OBD-II powertrain diagnostic trouble code: Sensor Circuit Low Bank 1. It is logged by the engine control unit when the scr/adblue monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P2202
Group
Powertrain
System
SCR/AdBlue
Severity
Warning (MIL on, possible limp mode)
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What P2202 means

P2202 is a generic SAE powertrain code that sets when the engine control module (ECM) or diesel control unit (DCU) detects a voltage signal from the upstream NOx sensor (Bank 1, Sensor 1) that falls below the expected operating range. The NOx sensor is a critical component of the Selective Catalytic Reduction (SCR) / AdBlue emissions system, measuring oxides of nitrogen in the exhaust stream before the SCR catalyst.

A 'circuit low' condition typically means the ECM is reading a voltage on the NOx sensor signal wire that is at or near ground potential, indicating either a short to ground in the wiring harness, a failed sensor element, or an open in the reference/supply voltage feed. Because this code directly impairs SCR dosing control, most modern diesel vehicles will illuminate the MIL and may progressively restrict engine output.

P2202 is one of four sibling codes covering the Bank 1 Sensor 1 NOx circuit: P2200, P2201, P2202, P2203.

Common causes

Most-frequently reported root causes when P2202 is logged.

  • 1
    Wiring harness short to ground on the NOx sensor signal or supply circuit
  • 2
    Corroded, damaged, or water-ingressed NOx sensor connector
  • 3
    Failed NOx sensor element (internal short or open circuit)
  • 4
    Broken or chafed wiring between the NOx sensor and ECM/DCU
  • 5
    Faulty ECM/DCU NOx sensor input circuit (rare)
  • 6
    Poor ground connection at the sensor or engine harness ground point
  • 7
    Aftermarket or non-OEM NOx sensor with incompatible signal characteristics

Symptoms drivers notice

MIL (Check Engine / Engine Management light) illuminated
AdBlue/DEF system warning or SCR fault message in instrument cluster
Increased NOx emissions (SCR dosing disabled or inaccurate)
Possible engine torque/speed derate after extended fault persistence
Possible AdBlue consumption anomaly (over- or under-dosing)

How to diagnose P2202

A typical diagnostic flow when this code is present.

  1. 1
    Perform a full scan and record all stored and pending codes
  2. 2
    Inspect the NOx sensor wiring harness and connector
  3. 3
    With the ignition on, measure the supply voltage and ground at the NOx sensor connector
  4. 4
    Measure the signal wire voltage at the connector with the sensor unplugged
  5. 5
    If wiring checks pass, substitute or test the NOx sensor
  6. 6
    Clear codes and perform a drive cycle; if P2202 returns without P2201/P2203 and wiring is confirmed good, replace the NOx sensor
  7. 7
    After repair, verify with a scan tool that NOx sensor live data reads plausibly

Vehicles where we've handled P2202

Platforms in our catalogue with confirmed P2202 coverage.

BMW 530XD
2017
BMW X5
2018–2019
AUDI A4 20D
VW TRANSPORTER
BMW 320D
2016
AUDI A6
2015
AUDI A7
BMW 530XD 30D

Related powertrain codes

Frequently asked questions

Can I drive with code P2202 active?

Short-term driving is possible. Many Euro 5/6 and EPA-compliant diesel vehicles impose a progressive torque derate after a set number of drive cycles with an active SCR fault.

Will P2202 clear itself if the fault is intermittent?

If the underlying cause is intermittent, the code may move from active to pending and eventually clear after the required number of clean drive cycles.

Is P2202 the same as a failed NOx sensor?

Not necessarily. A circuit low code points to a voltage on the signal wire that is too close to ground, more commonly caused by a wiring short or corroded connector.

Does P2202 affect AdBlue/DEF consumption?

Yes. When the ECM cannot read a valid NOx signal it typically defaults to a fixed or zero dosing strategy.

Disabling P2202 in software

RaceTune can permanently disable P2202 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

ECUs with a P2202 disable in our catalogue

Confirmed coverage from our recipe database — we support many more families. Upload your file and our identifier will match it automatically.

  • Bosch EDC17C60 verified 2 software versions
  • Bosch EDC17C74 verified 2 software versions
  • Bosch EDC17C50 verified 1 software version
  • Bosch EDC17C56 verified 1 software version
  • Bosch EDC17CP44 verified 1 software version
  • Bosch MD1CP002 verified 1 software version
  • Bosch MD1CP004 verified 1 software version
  • Bosch MD1CS001 verified 1 software version

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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