Powertrain (Engine & Gearbox)Standard EOBD

P0164 - O2 Sensor Circuit High Voltage (Bank 2, Sensor 3)

Q: What are the symptoms of fault code P0164?

• Check engine light (MIL) illuminated • Increased fuel consumption • Rough idling (if rich condition is present) • Failed emissions test • Smell of unburned fuel from the exhaust

Q: What causes fault code P0164?

• Most likely: Faulty Oxygen Sensor (internal short) • Likely: Short circuit to battery voltage (12V) in the wiring harness • Possible: Faulty fuel pressure regulator or leaking injector (causing rich condition) • Rare: Corroded connector causing a bridge between pins • Rare: Faulty Engine Control Module (ECM/PCM)

Q: How do you fix fault code P0164?

STEP 1: Visually inspect the connector at Sensor 3 (Bank 2) for melted wires or corrosion. Clean if necessary. STEP 2: Use a scan tool to monitor O2 sensor voltage in Live Data. Voltage should vary between 0.1V and 0.9V. If stuck above 1.1V, proceed. STEP 3: Check the wiring harness. Measure resistance between the signal wire and ground, and between signal and 12V. There should be no continuity (Infinite Ohm). STEP 4: Check the heater circuit. If the heater element shorts internally to the signal wire, P0164 will trigger. STEP 5: If wiring is verified good, replace the O2 Sensor (Bank 2, Sensor 3).

Last updated:1 February 2026

Related:O2 Sensor (Bank 2, Sensor 3), Wiring Harness, ECM (Engine Control Module), Fuel Pressure Regulator

System

Powertrain (Engine & Gearbox)

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Technical Description

P0164 marks a condition where the Engine Control Module (ECM) detects that the Oxygen (O2) sensor voltage on Bank 2, Sensor 3 remains above the normal operating range (typically >1.2V). This sensor is located downstream of the catalytic converter and monitors emission efficiency. A high voltage signal usually points towards an excessively rich air-fuel ratio or an electrical short circuit to voltage within the sensor harness or the sensor itself.

Possible Causes

Faulty Oxygen Sensor (internal short)

Short circuit to battery voltage (12V) in the wiring harness

Faulty fuel pressure regulator or leaking injector (causing rich condition)

Corroded connector causing a bridge between pins

Faulty Engine Control Module (ECM/PCM)

Symptoms

Check engine light (MIL) illuminated

Increased fuel consumption

Rough idling (if rich condition is present)

Failed emissions test

Smell of unburned fuel from the exhaust

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P0164 - O2 Sensor Circuit High Voltage (Bank 2, Sensor 3)

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P0164 - O2 Sensor Circuit High Voltage (Bank 2, Sensor 3)

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Technical Description

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Symptoms

Recommended Solution

Workflow

Mechanic's Tip

Do you also have other fault codes?

Do you also have
other fault codes?