P2238

O2 Sensor Positive Current Control Circuit Low Bank 1 Sensor 1

Q: Is it safe to drive with P2238?

Yes, for the short term. The car runs in open-loop with slightly worse economy, but there is no stalling risk; repair it before it affects emissions or the catalyst.

Q: Can I just clear P2238?

It returns until the sensor or its current-control circuit is repaired, since the ECM monitors that circuit whenever the sensor is active.

Fuel & air metering (O2 sensor) Generic OBD-II Medium

What it means

P2238 means the ECM detected a low-voltage condition in the positive pump-current control circuit of the upstream wideband air-fuel (O2) sensor on bank 1, sensor 1. This circuit lets the sensor measure the exhaust mixture; with it faulted the ECM runs open-loop, so the car stays drivable but may idle rough and use a little more fuel until the sensor or wiring is fixed.

Medium

Can I keep driving? Drivable — with the upstream sensor circuit faulted the ECM runs open-loop, so expect slightly worse economy and possibly rough idle, but no stalling risk.

Real-world scan data

Seen in

247

scans in the past year

Found in

<0.1%

of scans

0.1%

of scans that found faults

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Slightly rough or uneven idle
Increased fuel consumption
Minor hesitation or surging

Common causes

Most likely first

Faulty upstream air-fuel ratio (wideband O2) sensor, bank 1 sensor 1Likely
Low voltage / short-to-ground in the sensor's pump-current control wiringCommon
Poor or corroded connection at the sensorCommon
Faulty ECM/PCM driverLess often

How to diagnose & fix

Work through it in order

Read freeze-frame and check for companion sensor codes (P2237, P2239, P2231).
Inspect the bank 1 sensor 1 connector and wiring for corrosion, chafing, or exhaust-heat damage.
Check the pump-current control circuit for a short to ground or high resistance.
Confirm the ECM is supplying the correct control signal to the sensor.
If the wiring is good, replace the bank 1 sensor 1 air-fuel/O2 sensor and retest.

FAQ

Quick answers

Is it safe to drive with P2238?+

Yes, for the short term. The car runs in open-loop with slightly worse economy, but there is no stalling risk; repair it before it affects emissions or the catalyst.

Can I just clear P2238?+

It returns until the sensor or its current-control circuit is repaired, since the ECM monitors that circuit whenever the sensor is active.

Read & clear P2238 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX