P0164: O2 Sensor Circuit High Voltage (Bank 2 Sensor 3)
Check engine light illumination; possible rough idle, minor power loss, reduced fuel economy
Overview
P0164 indicates a high voltage signal in the oxygen sensor circuit for Bank 2 Sensor 3, typically meaning the downstream O2 sensor is producing voltage above expected range due to sensor failure, wiring issues, or PCM faults.
Common Symptoms
- Check engine light (CEL) illuminated
- Rough idle or hesitation during acceleration
- Reduced fuel efficiency
- Increased emissions or failed emissions test
Most Common Causes
Sensor internally shorted or producing abnormally high voltage output
Short to power or poor ground raising circuit voltage
Extra air entering can skew sensor readings and cause high voltage
Poor signal interpretation or controller circuit failure
Diagnostic Steps
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Connect a professional OBD-II scanner to confirm P0164 and check for related codesExpected: P0164 stored; note any other oxygen sensor related codesInterpretation: Confirm code validity and any supporting faults
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Perform a visual inspection of Bank 2 Sensor 3 wiring and connectorsExpected: No corrosion, no broken pins, insulation intactInterpretation: Good wiring reduces probability of circuit faults
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Measure O2 sensor voltage with multimeter (signal to ground)Expected: Voltage should fluctuate roughly 0.1–0.9 V under normal conditionsInterpretation: If voltage is consistently high (>0.9 V), sensor or wiring issue likely
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Check for exhaust system leaks near the sensor locationExpected: No audible leaks or visible damageInterpretation: Absence of leaks suggests issue is electrical rather than physical air intrusion
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If wiring and sensor checks good, evaluate PCM O2 sensor driver with advanced diagnostic toolExpected: No abnormal driver flagsInterpretation: If PCM shows faults, PCM or its calibration may be considered
Repair Solutions
Most common repair; cost varies by vehicle and part brand
Cost depends on extent of wiring repair needed
Depends on leak location and labor involved
Consider only after ruling out sensor and wiring issues
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Incorrectly assuming catalytic converter failure without verifying O2 sensor circuit integrity
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