P1143 – Heated Oxygen Sensor 1 Lean Shift Monitoring, Bank 1

P1143 Possible Causes

  • Faulty heated oxygen sensor upstream, bank 1
  • Intake air leaks
  • Heated oxygen sensor upstream circuit bank 1 is open or shorted
  • Poor electrical connection in the heated oxygen sensor upstream circuit, bank 1
  • Fuel pressure
  • Injectors

How to Fix Code P1143?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

  • Engine light on (or engine service warning light soon)

P1143 Meaning

The heated oxygen sensor 1 is placed in the upstream pipe. It detects the amount of oxygen in the exhaust gases compared to the outside air. The heated oxygen sensor 1 has a closed-end zirconia ceramic tube. Zirconia generates a voltage from about 1 V under richer conditions to 0 V under leaner conditions. The heated oxygen sensor 1 signal is sent to the engine control module (ECM). The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the abrupt change from 1V to 0V.

P1143 2002 NISSAN ALTIMA SEDAN – Heated Oxygen Sensor 1 Bank 1 Lean Shift Monitoring

P1143 2002 NISSAN ALTIMA SEDAN Possible Causes

  • Faulty heated oxygen sensor, bank 1
  • Intake air leaks
  • Open or short circuit in the heated oxygen sensor bank 1 harness
  • Poor electrical connection in the heated oxygen sensor circuit, bank 1
  • Fuel pressure
  • Injectors

How to Fix Code P1143 2002 NISSAN ALTIMA SEDAN?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Technical Notes

If there is no intake air leak, the most likely cause of code P1143 is the front O2 sensor bank 1.

When is the Code Detected?

The maximum and minimum sensor voltages are not reached at the specified voltages.

Possible Symptoms

  • Engine light on (or service engine soon warning light)

P1143 2002 NISSAN ALTIMA SEDAN Meaning

The heated oxygen sensor 1 is placed in the front pipe. It detects the amount of oxygen in the exhaust gases compared to the outside air. The heated oxygen sensor 1 has a closed-end zirconia ceramic tube. Zirconia generates a voltage from about 1 V under richer conditions to 0 V under leaner conditions. The heated oxygen sensor 1 signal is sent to the engine control module (ECM). The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the sharp change from 1V to 0V.

P1143 2003 INFINITI G35 – Heated Oxygen Sensor 1 Lean Shift Monitoring, Bank 1

P1143 2003 INFINITI G35 Possible Causes

  • Faulty Heated Oxygen Sensor, Bank 1, Sensor 1
  • Intake Air Leaks
  • Open or Short Circuit in Bank 1, Sensor 1 Heated Oxygen Sensor Harness
  • Poor Electrical Connection in Bank 1, Sensor 1 Heated Oxygen Sensor Circuit
  • Fuel Pressure
  • Fuel Injectors

How to Fix Code P1143 2003 INFINITI G35?

Start by checking the “Possible Causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Technical Notes

If there is no intake air leak, the most likely cause of the P1143 code is the Bank 1, Sensor 1 O2 sensor.

When is the Code Detected?

The maximum and minimum sensor voltages are not reached at the specified voltages.

Possible Symptoms

  • Check Engine Light On (or Service Engine Soon Warning Light)

P1143 2003 INFINITI G35 Meaning

The Heated Oxygen Sensor 1 (Bank 1, Sensor 1) is located in the front pipe. It detects the amount of oxygen in the exhaust gases compared to the outside air. The Heated Oxygen Sensor 1 has a closed-end zirconia ceramic tube. The zirconia generates a voltage from about 1 V under richer conditions to 0 V under leaner conditions. The signal from Heated Oxygen Sensor 1 is sent to the Engine Control Module (ECM). The ECM adjusts the fuel injection pulse width to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the steep change from 1V to 0V.

P1143 AUDI – Upper Limit Exceeded in Cross-Check Calculation of Load

P1143 AUDI Possible Causes

  • Faulty mass air flow (MAF) sensor
  • Vacuum leaks
  • Throttle system errors

How to Fix P1143 AUDI Code?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

  • Check engine light on (or service engine soon warning light)

P1143 AUDI Meaning

Load Calculation Cross Check Upper Limit Exceeded is the generic description for Audi P1143 code, but the manufacturer may have a different description for your vehicle model and year. Currently, we don’t have more information about the Audi P1143 OBDII code.

P1143 BUICK – HO2S Sensor Bank 1 Sensor 3 Low Voltage

P1143 BUICK Possible Causes

  • Faulty oxygen sensor, bank 1
  • Bank 1 oxygen sensor harness is open or shorted
  • Poor electrical connection in oxygen sensor circuit, bank 1

How to Fix P1143 BUICK Code?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

  • Engine light on (or service engine soon warning light)

P1143 BUICK Meaning

HO2S Bank 1 Sensor 3 Low Voltage is the generic description for Buick P1143 code, but the manufacturer may have a different description for your specific model and vehicle year. Currently, we don’t have more information about OBDII P1143 Buick code.

P1143 CADILLAC – Bank 1 Sensor 3 HO2S Low Voltage

Code P1143 CADILLAC: Causes, Symptoms, and Repairs

1. Meaning of Code P1143 CADILLAC

The code P1143 is a diagnostic trouble code (DTC) related to the oxygen sensor (HO2S) Bank 1, Sensor 3.

Function of the Oxygen Sensor (HO2S)

  • It measures the amount of oxygen in the exhaust gases.
  • It sends this information to the engine control module (ECM).
  • The ECM then adjusts the air-fuel mixture to optimize combustion.
  • A voltage that is too low means the sensor is not working correctly.

This code can indicate a problem with a faulty HO2S sensor or damaged wiring.

2. Possible Symptoms of Code P1143

  • Check Engine Light illuminated
  • Increased fuel consumption
  • Irregular idle
  • Increased pollutant emissions

3. Possible Causes of Code P1143

Code P1143 can be caused by:

  • Faulty oxygen sensor (Bank 1, Sensor 3)
  • Open or short circuit in the HO2S sensor harness
  • Poor electrical connection in the HO2S circuit

4. How to Repair Code P1143 CADILLAC?

1. Check the condition of the wiring and connectors

  • Visually inspect the HO2S sensor harness.
  • Look for cut, melted, or corroded wires.
  • Check the connector pins (broken, bent, or corroded).

2. Test the oxygen sensor with a multimeter

  • Disconnect the sensor and measure the voltage with a multimeter.
  • The voltage should vary between 0.1V and 0.9V when the engine is hot.
  • If the voltage is stuck or absent, replace the sensor.

3. Check the sensor signal with an OBD-II scanner

  • Read the HO2S sensor’s real-time values.
  • If the values remain constant, suspect a faulty sensor.

4. Clear the Code and Test the Vehicle

  • Clear the error code with an OBD-II scanner.
  • Perform a road test to check if the code reappears.

Conclusion

The code P1143 CADILLAC is often caused by a faulty oxygen sensor or a wiring problem. An accurate diagnosis following the steps above will resolve the issue and improve engine performance and fuel consumption.

P1143 CHEVROLET – Bank 1 Sensor 3 HO2S Lean or Low Voltage System

P1143 CHEVROLET Possible Causes

  • Faulty oxygen sensor, bank 1
  • Bank 1 oxygen sensor harness is open or shorted
  • Poor electrical connection in oxygen sensor circuit, bank 1

How to Fix Code P1143 CHEVROLET?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

  • Engine light on (or service engine soon warning light)

P1143 CHEVROLET Meaning

HO2S Bank 1 Sensor 3 Lean System or Low Voltage is the generic description for Chevrolet code P1143, but the manufacturer may have a different description for your vehicle model and year. Currently, we have no further information about Chevrolet OBDII code P1143.

P1143 CHRYSLER – Fuel Rail Pressure Malfunction Positive Pressure Deviation

P1143 CHRYSLER Possible Causes

  • Poor fuel pressure
  • Faulty fuel rail pressure solenoid
  • Fuel rail pressure solenoid harness is open or shorted
  • Poor electrical connection in the fuel rail pressure solenoid circuit
  • Air in the fuel system

How to Fix Code P1143 CHRYSLER?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

When is the Code Detected?

The Engine Control Module (ECM) has determined that the fuel rail pressure is too high for a specific condition

Possible Symptoms

  • Engine light on (or service engine soon warning light)

P1143 CHRYSLER Meaning

Fuel Rail Pressure Malfunction – Positive Pressure Deviation is the generic description for Chrysler code P1143, but the manufacturer may have a different description for your vehicle model and year. Currently, we do not have more information about the Chrysler P1143 OBDII code.

P1143 DODGE – Fuel Rail Pressure Malfunction Positive Pressure Deviation

P1143 DODGE Possible Causes

  • Poor fuel pressure
  • Faulty fuel rail pressure solenoid
  • Fuel rail pressure solenoid harness is open or shorted
  • Poor electrical connection in the fuel rail pressure solenoid circuit
  • Air in the fuel system

How to Fix P1143 DODGE Code?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

When is the Code Detected?

The Engine Control Module (ECM) has determined that the fuel rail pressure is too high for a specific condition

Possible Symptoms

  • Engine light on (or service engine soon warning light)

P1143 DODGE Meaning

Fuel Rail Pressure Malfunction Positive Pressure Deviation is the generic description for P1143 Dodge code, but the manufacturer may have a different description for your vehicle model and year. Currently, we don’t have more information about the P1143 Dodge OBDII code.

P1143 GMC – HO2S, Bank 1 Sensor 3, Lean or Low Voltage System

P1143 GMC Possible Causes

  • Faulty oxygen sensor, bank 1
  • Bank 1 oxygen sensor harness is open or shorted
  • Poor electrical connection in oxygen sensor circuit, bank 1

How to Fix GMC Code P1143?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

  • Engine light on (or service engine soon warning light)

P1143 GMC Meaning

HO2S, bank 1 sensor 3, lean system or low voltage is the generic description for GMC code P1143, but the manufacturer may have a different description for your vehicle model and year. Currently, we have no further information about OBDII code P1143 GMC.