P1172 - Rear A/F Sensor Bank 1 Sensor 1 Circuit Out Of Range High

Repair Importance Level: 3/3
Repair Difficulty Level: 2/3    What is this?
Table of contents

P1172 Possible Causes

  • Faulty Air/Fuel Ratio Bank 1 Sensor 1
  • Air/Fuel Ratio Bank 1 Sensor 1 harness is open or shorted
  • Air/Fuel Ratio Bank 1 Sensor 1 circuit poor electrical connection

How do I fix code P1172?

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's pins.

Cost of diagnosing the P1172 code

Labor: 1.0

The cost of diagnosing the P1172 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P1172 Description

The Air/Fuel Ratio (A/F) sensor 1 is installed in the exhaust system and detects oxygen content in the exhaust gas. The A/F sensor transmits output voltage to the Engine Control Module (ECM). A heater for the sensor element is embedded in the A/F sensor (sensor 1). It is activated and heats the sensor to stabilize and speed the detection of oxygen content by controlling current flowing through the heater. An increase in the current levels off as the applied voltage to the element electrode reaches a certain range because the amount of oxygen which is led through the diffusion layer is limited. The current amperage is proportional to oxygen content in the exhaust gas, so the air/fuel ratio is detected by the measurement of the current amperage. The ECM compares a set target air/fuel ratio with the detected air/fuel ratio and controls the fuel injection timing.
If the A/F sensor (sensor 1) voltage is low, the air/fuel ratio is lean, and the ECM uses A/F feedback control to issue a Rich command. If the A/F sensor (sensor 1) voltage is high, the air/fuel ratio is rich, and the ECM uses A/F feedback control to issue a Lean command.
OBDII Code P1172 - Rear A/F Sensor Bank 1 Sensor 1 Circuit Out Of Range High - AutoCodes.com

More Information

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