How do you fix fault code P014B?

STEP 1: Inspect the exhaust system for leaks near the sensor. Even minor pinhole leaks can affect response rates. STEP 2: Inspect the sensor connector for moisture or corrosion. Measure heater circuit resistance (typically 2-20 Ohms). STEP 3: Use a scan tool to monitor Live Data. Perform a snap throttle test followed by deceleration. The voltage should drop instantly below 0.2V. If it lags, the sensor is contaminated or aged. STEP 4: Replace the O2 sensor (Bank 1, Sensor 2). Clear codes and perform a drive cycle.

Powertrain (Engine & Gearbox)Standard EOBD

P014B - O2 Sensor Delayed Response - Rich to Lean (Bank 1, Sensor 2)

Q: What are the symptoms of fault code P014B?

• Check engine light (MIL) illuminated • Decreased fuel economy • Failed emission test • Slight smell of raw fuel at idle

Q: What causes fault code P014B?

• Most likely: Fouled or aged Oxygen Sensor (Bank 1, Sensor 2) • Likely: Exhaust leak near the sensor (introducing ambient air) • Possible: Wiring harness damage or connector corrosion (high resistance) • Rare: Leaking fuel injector causing residual rich exhaust • Rare: Faulty Engine Control Module (ECM) software logic

Last updated:1 February 2026

Related:Syresensor (O2 Sensor), Catalytic Converter, Engine Control Unit (ECU), Exhaust Manifold

System

Powertrain (Engine & Gearbox)

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Technical Description

P014B is stored when the Engine Control Unit (ECU) monitors the downstream oxygen (O2) sensor on Bank 1 and determines its response time from a rich to a lean condition is too slow. This typically occurs during deceleration fuel cut-off (DFCO) events. A functional sensor should rapidly drop voltage (from approx. 0.8V to below 0.2V). If the switching time exceeds the calibrated limit, the ECU flagging the sensor as 'sluggish' or 'aged'. This can affect the monitoring of catalyst efficiency.

Possible Causes

Fouled or aged Oxygen Sensor (Bank 1, Sensor 2)

Exhaust leak near the sensor (introducing ambient air)

Wiring harness damage or connector corrosion (high resistance)

Leaking fuel injector causing residual rich exhaust

Faulty Engine Control Module (ECM) software logic

Symptoms

Check engine light (MIL) illuminated

Decreased fuel economy

Failed emission test

Slight smell of raw fuel at idle

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P014B - O2 Sensor Delayed Response - Rich to Lean (Bank 1, Sensor 2)

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P014B - O2 Sensor Delayed Response - Rich to Lean (Bank 1, Sensor 2)

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Technical Description

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Symptoms

Recommended Solution

Workflow

Mechanic's Tip

Do you also have other fault codes?

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other fault codes?