P0142 The bank 1 sensor 3 oxygen sensor circuit is giving the computer a signal outside what it expects

O2 sensor circuit malfunction, bank 1 sensor 3

Severity not verified — if the car runs badly, have it inspected

The sources read for this code do not rate its urgency, so no severity is claimed. TroubleCodes.net describes the usual symptom as a check engine light, sometimes with poorer fuel economy or running; have it diagnosed rather than ignoring it.

Source: how we rate severity

P0142 in short

P0142 is a generic code for an oxygen sensor circuit malfunction on bank 1, sensor 3. The computer sees a voltage or signal from that sensor outside its limits. Wiring faults, blown fuses, a fouled or failed sensor and, rarely, the computer are the listed causes.

The Delaware DMV list and TroubleCodes.net both title P0142 as an O2 sensor circuit malfunction on bank 1 sensor 3. Bank 1 is the cylinder 1 side, and sensor 3 is a third sensor on that bank.

TroubleCodes.net describes the fault as the computer seeing a voltage or signal from that sensor that falls outside specification. It suggests recording codes, inspecting wiring and fuses, then watching sensor temperature and signal in closed loop.

Listed causes are damaged, shorted, open or corroded wiring, blown fuses, defective or fouled sensors and, rarely, a failed computer.

Most likely causes

These are general causes for this code across vehicles. None is specific to one make or model.

  1. Faulty or contaminated bank 1 sensor 3

    Common general cause
    Why it ranks here
    TroubleCodes.net lists the oxygen sensor itself as a leading cause, with a typical life under five years on some of its pages.
    What would change this
    Rises if the sensor's resistance is out of specification or its live data is stuck. Falls if the sensor tests within spec and the wiring is faulty.
    How to test the oxygen (o2) sensor

  2. Damaged, burned, corroded or disconnected wiring, connector or fuse

    Common general cause
    Why it ranks here
    The page lists wiring, connector and fuse faults caused by heat, road debris or corrosion.
    What would change this
    Rises if the harness is damaged or the connector is corroded or loose, or continuity fails. Falls if all circuit tests pass.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read all codes and freeze-frame data with a scan tool and record them before clearing.

    Low riskTool: OBD-II scan tool

    • IfOther oxygen sensor codes are stored

      It meansCheck shared wiring and fuses first.

      Go to step 2

    • IfP0142 is the only code

      It meansInspect the sensor wiring and look for exhaust leaks.

      Go to step 2

  2. With the exhaust cold, inspect the fuses, harness, connector and sensor for damage or corrosion and check the exhaust for leaks near the sensor.

    Use cautionTool: flashlight; fuse tester

    Warning:Exhaust parts and the sensor stay hot long after the engine is off and can cause serious burns. Work only on a cold exhaust and never under a car held up only by a jack.

  3. Use a multimeter to check circuit continuity (about 1 ohm or less end to end, and over 10 kilo-ohms to ground) and the sensor's internal resistance, then compare live sensor data.

    Use cautionTool: digital multimeter; scan tool

    Warning:Disconnect the sensor before testing resistance and keep the probes off live circuits. Use the figures for your own vehicle where the manual gives them; TroubleCodes.net's values are general.

Symptoms

  • Check engine light, with or without other symptoms
  • Rich or lean running
  • Lower fuel economy
  • Hesitation or rough idle

How to fix

  1. With the exhaust fully cold, inspect the sensor wiring, connector and fuses for damage or corrosion.

  2. Check the exhaust between the converter and the sensor for leaks.

Parts and cost context

  • Oxygen (O2) sensor:Replace the sensor only after wiring, fuses and exhaust leaks are checked. Use the part made for that bank and position. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Land Rover

  • 2015–2022 · Discovery Sport

    Supported by vehicle data

    Land Rover bulletin SSM75635 concerns Ingenium I4 2.0L petrol engines logging P0142, the oxygen sensor circuit bank 1 sensor 3. Whether it is still current is not verified.

  • 2022 · Range Rover

    Supported by vehicle data

    Land Rover bulletin SSM75635 concerns Ingenium I4 2.0L petrol engines logging P0142, the oxygen sensor circuit bank 1 sensor 3. Whether it is still current is not verified.

  • 2019–2022 · Range Rover Evoque

    Supported by vehicle data

    Land Rover bulletin SSM75635 concerns Ingenium I4 2.0L petrol engines logging P0142, the oxygen sensor circuit bank 1 sensor 3. Whether it is still current is not verified.

  • SSM75635Status unverified

    Ingenium 2.0L petrol logging P0142 (sensor 3, bank 1 oxygen sensor circuit)

    2015–2022discovery-sport, range-rover, range-rover-evoque · issued · NHTSA 10206277

    Land Rover service bulletin about Ingenium 2.0L petrol engines logging P0142. The summary is only the title and gives no repair.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Toyota

  • 2003–2004 · Camry

    Supported by vehicle data

    Toyota bulletin 01603 covers an ECM calibration update for a check engine light with P0142. Whether it is still current is not verified.

  • 01603Status unverified

    ECM calibration update for MIL on with P0142

    2003–2004camry · issued · NHTSA 10005251

    Toyota bulletin about a calibration update to the engine control module for a check engine light with P0142. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Ford

  • 2000 · Mustang

    Supported by vehicle data

    Ford bulletin 13816 says some 3.8L engines built before November 11, 1999 may show a check engine light with P0142 among several other oxygen sensor codes. Whether it is still current is not verified.

  • 13816Status unverified

    3.8L engines built before November 11, 1999: MIL with several oxygen sensor codes including P0142

    2000mustang · issued · NHTSA 612832

    Ford bulletin about some 3.8L engines built before November 11, 1999 that may show a check engine light with P0135, P0136, P0141, P0142, P0150, P0155, P0156 and P0161. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P0143The bank 1 sensor 3 oxygen sensor is reporting a voltage that is too low

    Same system Possible — needs testing

    P0143 is the low-voltage code for the same bank 1 sensor 3 circuit and starts with the same wiring and sensor checks.

  • P0144The bank 1 sensor 3 oxygen sensor is reporting a voltage that is too high

    Same system Possible — needs testing

    P0144 is the high-voltage code for the same circuit; check wiring, connectors and the sensor for all three.

All Oxygen sensors codes

P0142 questions

What does bank 1 sensor 3 mean?

Bank 1 is the side of the engine with cylinder 1. Sensor 3 is a third oxygen sensor on that bank; TroubleCodes.net describes it as monitoring exhaust oxygen downstream of the catalytic converter, so look at your vehicle's wiring diagram for its exact position.

Sources and review

  1. P0142 trouble code page — TroubleCodes.net
  2. SSM75635: Ingenium 2.0L petrol logging P0142 (sensor 3, bank 1 oxygen sensor circuit) — Land Rover
  3. 01603: ECM calibration update for MIL on with P0142 — Toyota
  4. 13816: 3.8L engines built before November 11, 1999: MIL with several oxygen sensor codes including P0142 — Ford
  5. On-Board Diagnostic Trouble Codes (generic code title list) — Delaware Division of Motor Vehicles
Last reviewed
Written by
Saurabh K.
Editorial review
Pending
Technician review
Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

My Car

Pick your car and code pages will point out notes and bulletins for it. Saved only in this browser.

Fill this in from your VIN

Used once to identify your engine; not stored.