P0158 – O2 Sensor Circuit High Voltage (Bank 2, Sensor 2)

DTC Data Sheet
SystemPowertrain
StandardSAE J2012 / ISO 15031-6
Fault typeCircuit High
Official meaningO2 Sensor Circuit High Voltage (Bank 2, Sensor 2)

Bank 2 downstream O2 sensor signal is stuck high — typically a permanently rich exhaust or contaminated sensor.

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⚠ High-Voltage Safety Note: This code relates to a hybrid or EV system. The sensor and wiring circuit itself is low voltage, but it is located near high-voltage components. Always follow manufacturer HV safety procedures before working in the motor electronics area. You do not need to open HV components to diagnose this circuit, but HV isolation and PPE requirements still apply.

P0158 Quick Answer

Bank 2 downstream O2 sensor signal is stuck high — typically a permanently rich exhaust or contaminated sensor.

What Does P0158 Mean?

O2 Sensor Circuit High Voltage (Bank 2, Sensor 2). Bank 2 downstream O2 sensor signal is stuck high — typically a permanently rich exhaust or contaminated sensor.

Symptoms

  • Check engine light
  • Black exhaust smoke if rich is severe
  • Possible co-codes: P0172, P0175

Common Causes

  • Bank 2 rich condition (leaking injector, high fuel pressure)
  • Sensor contamination (silicone, coolant, oil)
  • Failed sensor stuck high
  • Short to power on the signal wire

Diagnosis Steps

You’ll need a scan tool capable of reading live powertrain data, a digital multimeter, and access to the wiring diagram for the specific platform.

  1. Read bank 2 downstream voltage. Stuck above 0.9 V indicates rich or contamination.
  2. Verify upstream O2 behavior — if upstream is also rich, the issue is fueling, not the sensor.
  3. Check for fuel-pressure or injector leaks.

Possible Fixes

  • Address rich-condition root cause (injector, regulator)
  • Bank 2 downstream O2 sensor replacement when contaminated

Can I Still Drive With P0158?

The vehicle will usually still drive with P0158 stored, but performance, drivability, or emissions will be degraded. The PCM may inhibit emissions monitors and limit closed-loop fueling adjustments. Drive to a workshop, but don’t ignore the code long-term — degraded sensor data can mask other faults and shorten catalyst life.

How Serious Is This Code?

P0158 is a moderate-priority fault. It will not prevent the engine from running but unaddressed it can damage the catalytic converter, reduce fuel economy, or cause failed emissions testing. Address within a few drive cycles.

Brand-Specific Guides for P0158

Manufacturer-specific diagnostic procedures with factory data and pin-level details for vehicles where this code commonly sets:

Compare nearby o2 voltage trouble codes with similar definitions, fault patterns, and diagnostic paths.

  • P0152 – O2 Sensor Circuit High Voltage (Bank 2, Sensor 1)
  • P0157 – O2 Sensor Circuit Low Voltage (Bank 2, Sensor 2)
  • P0151 – O2 Sensor Circuit Low Voltage (Bank 2, Sensor 1)
  • P0161 – O2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 2)
  • P0160 – O2 Sensor Circuit No Activity Detected (Bank 2, Sensor 2)
  • P0159 – O2 Sensor Circuit Slow Response (Bank 2, Sensor 2)

FAQ

Will P0158 clear itself?

Only if the underlying fault was intermittent and self-corrected. Most root causes are persistent and require physical repair.

Can I clear P0158 without fixing it?

You can clear it with a scan tool, but it will return as soon as the fault condition reappears — typically within one or two drive cycles.

Is P0158 related to other codes?

Often, yes. Adjacent codes in the same circuit or system frequently set together — if P0158 is present, scan for related codes and address them as a group.