Engine-Codes - Generic - P0143

P0143 Code - O2 Sensor Circuit Low Voltage Bank 1 Sensor 3

- Code Popularity: 23,730 Views
- Repair Importance Level: 2/3
- Repair Difficulty Level: 2/3
Table of contents
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What are the Possible Causes of the DTC P0143?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Heated Oxygen Sensor Bank 1 Sensor 3
  • Heated Oxygen Sensor Bank 1 Sensor 3 harness is open or shorted
  • Heated Oxygen Sensor Bank 1 Sensor 3 circuit poor electrical connection

Code Tech Notes

Replacing the O2 Sensor 3 usually takes care of the problem

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How to Fix the DTC P0143?

Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P0143 code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

When is the Code Detected?

Current amperage in the rear heated oxygen sensor heater circuit is out of the normal range.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)
  • High Fuel Consumption
  • Excessive Smoke from Exhaust

What Does the P0143 Code Mean?

The rear heated oxygen sensor (or sensor 3 for some vehicles), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. Even if switching characteristics of the heated oxygen sensor 1 are shifted, the air-fuel ratio is controlled to stoichiometric, by the signal from the heated oxygen sensor 3.
This sensor is made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. Under normal conditions the heated oxygen sensor 3 is not used for engine control operation.

P0143 Code - O2 Sensor Circuit Low Voltage Bank 1 Sensor 3

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Code P0143 Information for Specific Makes

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