P2237
O2 Sensor Positive Current Control Circuit/Open Bank 1 Sensor 1
The engine computer found a problem in the current-control circuit for the upstream oxygen or air-fuel ratio sensor on bank 1. This is usually an electrical fault in the sensor, connector, wiring, or PCM control path. Because this sensor is used for fuel control, the engine may run rich, lean, or unstable.
- SEV
- 3/5
- DRIVE
- CAUTION
- DIY
- $20-$180
- SHOP
- $120-$500
Quick answer
AI-CITATION READYWhat it means
Can you drive with it?
Most common causes
- Failed Bank 1 Sensor 1 oxygen or air-fuel ratio sensor
- Open circuit, damaged wiring, or poor connector contact in the positive current control circuit
- Corrosion, water intrusion, or heat damage at the sensor connector
Typical repair cost
DIY usually runs $20-$180. Typical shop repair lands around $120-$500, depending on the root cause.
01 / Definition
P2237 means the PCM detected an open circuit or fault in the positive current control circuit for Bank 1 Sensor 1. On many vehicles this is a wideband air-fuel ratio sensor rather than a simple narrowband O2 sensor, and the PCM monitors current flow instead of only voltage switching. The code usually points to a failed sensor, damaged wiring, connector corrosion, terminal spread, or a problem in the current-control path between the PCM and the sensor. Because this upstream sensor is critical to fuel control, the engine can run rich, lean, hesitate, or fall back to default fueling when the fault is present.
02 / Drive status
With caution. You may be able to drive short distances, but fuel control, emissions, and drivability may be affected. If the engine runs rough, hesitates, or the check engine light is flashing, do not keep driving.
03 / Symptoms
- Check engine light on
- Poor fuel economy
- Rough idle
- Hesitation or poor acceleration
- Hard starting or unstable cold-start operation
- Failed emissions test
- Possible companion fuel-trim or oxygen-sensor codes
04 / Causes
| 1 | Failed Bank 1 Sensor 1 oxygen or air-fuel ratio sensor | high |
|---|---|---|
| 2 | Open circuit, damaged wiring, or poor connector contact in the positive current control circuit | high |
| 3 | Corrosion, water intrusion, or heat damage at the sensor connector | high |
| 4 | PCM driver or current-control circuit fault | medium |
| 5 | Incorrect sensor fitment or harness repair causing the wrong current-control characteristics | medium |
| 6 | Exhaust leak or engine condition causing abnormal upstream sensor behavior | low |
05 / Diagnostic sequence
- 01Scan for all stored, pending, and history codes and save freeze-frame data before clearing anything.
- 02Check for related fuel-trim, heater, air-fuel ratio, or oxygen-sensor circuit codes first.
- 03Inspect the Bank 1 Sensor 1 connector and wiring for corrosion, broken pins, melted insulation, or stretched wiring near the exhaust.
- 04Verify the correct sensor is installed and that any prior harness repair did not swap terminals or change resistance in the circuit.
- 05Verify power, ground, reference, and current-control circuit integrity according to the service information.
- 06Use a scan tool to review upstream sensor behavior, commanded equivalence ratio or lambda, and fuel trims at idle and under light load.
- 07Check for connector contamination from oil, coolant, or water intrusion.
- 08Inspect for exhaust leaks near the upstream sensor that could affect sensor operation.
- 09Load-test suspect wires and terminals if voltage checks look normal but the circuit opens when the harness is moved.
- 10Replace the sensor if circuit integrity tests good but the sensor still fails output or current-control checks.
- 11If the problem remains, inspect PCM outputs and related circuit control only after external faults are ruled out.
06 / Repairs
| 1 | Repair open wiring, loose terminals, or connector corrosion in the Bank 1 Sensor 1 circuit | $20-$180 |
|---|---|---|
| 2 | Replace the Bank 1 Sensor 1 oxygen or air-fuel ratio sensor if it fails testing | $60-$300 |
| 3 | Correct wrong sensor fitment, poor splice repairs, or harness routing problems that keep the current-control circuit unstable | $20-$250 |
| 4 | Repair exhaust leaks or connector contamination affecting upstream sensor operation | $20-$300 |
| 5 | Diagnose PCM current-control faults only after the sensor and wiring test good | $150-$900 |
07 / Related codes
08 / FAQ
What is Bank 1 Sensor 1 on P2237?
It is the upstream oxygen or air-fuel ratio sensor on the side of the engine with cylinder 1.
Can wiring cause P2237?
Yes. An open circuit, connector corrosion, or damaged wiring is one of the most common causes.
Is P2237 the same as a bad O2 heater code?
No. This code points to the sensor current-control circuit, not specifically the heater circuit, although related heater or sensor codes may appear at the same time.
Will P2237 affect drivability?
Yes, it can. Because the upstream sensor is used for fuel control, the engine may idle poorly, hesitate, or use more fuel.
09 / Source and method
- DATA BASIS
- OBD-II REFERENCE + OBD2.HELP
- METHOD
- STATIC VALIDATION
- SAFETY
- INFORMATIONAL
This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.
Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.
Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.