Air-Fuel Ratio Sensor Circuit High Voltage Bank 1 Sensor 1 (Honda)
What does P1158 mean?
The P1158 code means the vehicle's onboard diagnostic system has detected: Air-Fuel Ratio Sensor Circuit High Voltage Bank 1 Sensor 1 (Honda). This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Engine running lean
- Misfiring or rough idle
- Poor fuel economy
- Hesitation under load
Probable Causes (Ranked by Likelihood)
- Faulty air-fuel ratio sensor producing high voltage Very High
- Open circuit in A/F sensor ground wire High
- Rich running condition causing sensor saturation Moderate
- Fuel pressure too high (stuck fuel pressure regulator) Moderate
- ECM reference voltage issue Low
Step-by-Step Diagnostic Procedure
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Monitor A/F sensor voltage on a scan tool -- should fluctuate around a central value
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Check the sensor ground circuit for continuity
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Test fuel pressure and compare to Honda specifications
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Inspect for leaking fuel injectors that could cause rich condition
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Replace the A/F sensor if voltage is stuck high
Frequently Asked Questions
What causes high voltage from the A/F sensor?
High voltage typically means the sensor is detecting a rich exhaust condition. However, a faulty sensor with an internal open circuit can also produce a fixed high voltage reading regardless of actual exhaust conditions.
Can a fuel pressure regulator cause P1158?
Yes. A stuck-closed or leaking fuel pressure regulator can cause excessive fuel pressure, which leads to a rich condition. This causes the A/F sensor to read high voltage consistently.
Should I use Honda OEM A/F sensors?
Honda OEM Denso sensors are recommended for best compatibility and longevity. Aftermarket sensors may work but Honda engines are particularly sensitive to sensor quality. Budget an extra cost for OEM reliability.