P22C1

Code

Generic P — Powertrain

O2 Sensor Negative Current Control Circuit High Bank 2 Sensor 2

Brand: Generic

Type: P — Powertrain

Views: UK: 21 EN: 34 RU: 31

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Faulty bank 2 sensor 2 (wideband/UEGO)
Open, short or high-resistance wiring in sensor negative current/control circuit
Corroded or loose sensor connector or grounding point
Failed sensor heater or supply circuit fault
Exhaust leaks near the sensor or damaged sensor harness from heat/abrasion
Contaminated sensor (oil, coolant, silicone or fuel additives)

MIL (check engine light) illuminated
Possible failed emissions test or elevated tailpipe emissions
Stored O2 sensor-related fault codes and freeze-frame data showing abnormal sensor values
Possible poor fuel trim behavior or drivability issues (less common with downstream sensor)
Reduced fuel economy (in some systems)

Read and record all stored/related DTCs and freeze-frame data with a capable scan tool (include live data and fuel trims)
Confirm which physical sensor is Bank 2 Sensor 2 (downstream) before proceeding
Visually inspect sensor connector and wiring for damage, corrosion, burns, or pin platen issues
Check for exhaust leaks near the downstream sensor that could affect readings
Inspect ECM grounds and power feeds related to sensor circuits
Using a scan tool, monitor sensor parameters (pump current, sensor voltage, heater status) while engine is warm and under known conditions

Sensor type: downstream O2 (Bank 2 Sensor 2) — often UEGO/wideband on modern systems
Sensor output: linear UEGO signal; expected to vary near nominal values when system is healthy (specific values vehicle-dependent)
Pump/negative current: normally controlled around zero with small positive/negative excursions; sustained high negative current triggers the fault
Heater circuit: when commanded on, heater supply should be near battery voltage and the heater current within manufacturer spec
Control/reference signals: ECM should command and measure pump current; abnormal reading suggests wiring, sensor or ECM issue

Confirm the code and freeze-frame data with a scan tool. Record live data for Bank 2 Sensor 2 (pump current, sensor voltage, heater status, and comparison to Bank 1 Sensor 2 if available).
Perform a thorough visual inspection of the sensor connector, wiring, and nearby heat sources. Repair any obvious damage, corrosion, or chafing.
Check power and ground circuits: verify sensor heater supply fuse/relay, measure voltage at the connector with key on/engine off and while commanded on. Verify ECM ground integrity.
Measure continuity and resistance between the sensor negative/current control pin and the ECM pin; check for shorts to battery, ignition, or chassis ground.
Perform a wiggle test on harness and connector while watching live data to reveal intermittent faults.
If wiring and power/ground are good, test or bench-test the sensor per manufacturer procedure (measure pump cell current behavior or swap with a known-good identical sensor if available and harnesses are the same).
Check for exhaust leaks or catalytic converter damage that could cause abnormal downstream readings; repair as required.
If sensor replacement is required, install a correct OE or OE-equivalent downstream sensor, clear codes and road-test to verify. If new sensor shows same fault and wiring is confirmed good, suspect ECM fault and consider module diagnostics or replacement.
After repairs, erase codes and confirm no reoccurrence after a full drive cycle and that emissions-related monitors complete.

Damaged or chafed wiring to Bank 2 Sensor 2 causing intermittent short to voltage/ground
Connector corrosion or water intrusion at the sensor
Sensor element failure (pump cell or internal electronics) after prolonged service
Failed heater or blown fuse affecting sensor performance
Exhaust manifold/header or gasket leak upstream of the sensor causing abnormal readings