P2206

Code

Generic P — Powertrain

NOx Sensor Heater Control Circuit Low Bank 1 Sensor 1

Brand: Generic

Type: P — Powertrain

Views: UK: 25 EN: 45 RU: 26

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Malfunction Indicator Lamp (MIL) illuminated
Reduced emissions control performance or failed emissions test
Possible limp mode or reduced engine performance on some vehicles
Irregular diesel particulate filter (DPF) or SCR system behavior (diesel vehicles)
Stored diagnostic trouble code P2206 (and possibly related NOx heater codes)

Read freeze frame and live data with a scan tool; confirm P2206 presence and any related codes
Visual inspection of sensor connector and wiring for damage, corrosion, melting, or disconnection
Check relevant fuses and relays for the NOx/heater circuit
Backprobe heater supply and control wires with key on to verify battery voltage and control signal
Measure heater element resistance at the sensor (with sensor disconnected)
Perform continuity checks from ECM connector to sensor connector for supply, control, and ground

Heater supply voltage: near battery voltage with key on (typically ~11–14 V) at the fuse/relay feed
Heater element resistance: typically low (often around 1–30 ohms) — vehicle-specific; an open or very high resistance indicates failure
Heater current: when driven the ECM may allow several hundred milliamps to a few amps (vehicle-specific)
Control signal: may be a switched ground or PWM driver from ECM; expect switching activity when heater is active
Diagnostic threshold: ECM flags 'low' when measured voltage/current across the heater circuit is below a programmed threshold

Retrieve trouble codes and any freeze frame data with a scan tool. Note related codes for other NOx sensors or heater circuits.
Perform a visual inspection of Bank 1 Sensor 1 harness and connector. Repair obvious damage, water ingress, or corrosion.
Check fuses and relays that supply the NOx heater. Replace any blown fuses and retest.
With ignition on (engine off), backprobe the sensor connector to verify battery supply voltage at the heater supply pin and check for proper ground or control signal at the heater control pin.
Disconnect the sensor and measure heater element resistance across the heater terminals. Compare to vehicle-specific specification; an open or very high reading indicates a bad sensor.
Perform continuity and short-to-ground checks for heater supply and control wiring between the sensor connector and ECM. Repair shorts/opens as required.
If wiring and supply are good but heater does not draw expected current when commanded, test ECM output for proper switching. If ECM output is confirmed faulty, follow OEM procedures for ECM diagnosis/repair.
After repairs or sensor replacement, clear codes and perform a drive cycle or required relearn procedure. Verify code does not return and that heater operation is normal in live data.
Safety note: disconnect battery before performing connector repairs or when instructed by OEM procedures; avoid damaging emission control components.