P0158
O2 Sensor Circuit High Voltage (Bank 2 Sensor 2)
The engine computer is seeing too much voltage from the rear oxygen sensor on bank 2. This usually means the sensor is stuck rich, the wiring is damaged, or the sensor has failed. It can also be caused by an exhaust leak or an engine running too rich.
- SEV
- 3/5
- DRIVE
- CAUTION
- DIY
- $20–$120
- SHOP
- $150–$500
Quick answer
AI-CITATION READYWhat it means
Can you drive with it?
Most common causes
- Faulty Bank 2 Sensor 2 oxygen sensor
- Damaged, corroded, or melted wiring or connector at the rear O2 sensor
- Engine running too rich on bank 2 due to fuel system or injector issue
Typical repair cost
DIY usually runs $20–$120. Typical shop repair lands around $150–$500, depending on the root cause.
01 / Definition
P0158 means the powertrain control module has detected a high-voltage condition on the oxygen sensor circuit for Bank 2 Sensor 2, the downstream sensor after the catalytic converter on the bank opposite cylinder 1. The signal is staying above the expected range for too long, which suggests a sensor, wiring, exhaust, or fuel mixture problem rather than normal switching.
02 / Drive status
With caution. The vehicle may still run, but fuel economy and emissions can suffer. If the engine is running rich or the check engine light is flashing, avoid driving until it is diagnosed.
03 / Symptoms
- Check engine light on
- Poor fuel economy
- Rough running if engine is rich
- Failed emissions test
- Possible sulfur or fuel smell from exhaust
- Reduced catalyst monitoring accuracy
04 / Causes
| 1 | Faulty Bank 2 Sensor 2 oxygen sensor | high |
|---|---|---|
| 2 | Damaged, corroded, or melted wiring or connector at the rear O2 sensor | high |
| 3 | Engine running too rich on bank 2 due to fuel system or injector issue | medium |
| 4 | Exhaust leak, contamination, or sensor exposure to coolant/oil/fuel | medium |
| 5 | Blown fuse, poor ground, or power supply issue to the O2 sensor heater/circuit | low |
| 6 | PCM issue or incorrect PCM input interpretation | low |
05 / Diagnostic sequence
- 01Verify the code and check for related codes, especially fuel trim, misfire, and heater circuit codes.
- 02Inspect Bank 2 Sensor 2 wiring and connector for heat damage, corrosion, oil, or loose pins.
- 03Use a scan tool to view the sensor voltage and fuel trims; a stuck high reading should be confirmed.
- 04Check for exhaust leaks, especially near the sensor and upstream of it.
- 05Test the sensor heater circuit, power, ground, and signal wire with a multimeter according to factory specifications.
- 06Inspect fuel pressure and injector operation if the engine appears to be running rich.
- 07Replace the sensor only after wiring, exhaust, and mixture problems have been ruled out.
- 08Clear codes and perform a drive cycle to confirm the repair.
06 / Repairs
| 1 | Repair or replace damaged wiring, connector, or terminals at Bank 2 Sensor 2 | $20–$150 |
|---|---|---|
| 2 | Replace the Bank 2 Sensor 2 oxygen sensor if it is slow, stuck high, or out of specification | $50–$250 |
| 3 | Fix engine rich-running causes such as leaking injector, high fuel pressure, or faulty fuel pressure regulator | $100–$500 |
| 4 | Repair exhaust leaks or contamination issues affecting sensor readings | $50–$300 |
| 5 | Repair heater circuit power, ground, fuse, or PCM-related faults if present | $20–$300 |
07 / Related codes
08 / FAQ
What is Bank 2 Sensor 2?
It is the oxygen sensor located after the catalytic converter on the side of the engine that does not contain cylinder 1.
Can a bad oxygen sensor cause this code?
Yes. A failed rear oxygen sensor is one of the most common causes of P0158.
Will clearing the code fix the problem?
No. If the underlying fault is still present, the code will usually return.
Can a rich engine condition set P0158?
Yes. If the engine is running too rich, the downstream oxygen sensor can show a constant high voltage.
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.