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P1166 Acura Code - Air/Fuel Ratio Sensor 1 Heater Circuit Malfunction

- Code Popularity: 8,909 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 2/3
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What are the Possible Causes of the DTC P1166 Acura?

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 Air/Fuel Ratio Sensor 1
  • Air/Fuel Ratio Sensor 1 harness is open or shorted
  • Air/Fuel Ratio Sensor 1 circuit poor electrical connection
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How to Fix the DTC P1166 Acura?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1166 Acura code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

When is the Code Detected?

If the element is not activated or the Engine Control Module (ECM) terminal voltage is a set value or less for at least a set time period when the power is drawn to the A/F sensor (sensor 1) heater, a malfunction is detected and the code is stored.

What are Code Possible Symptoms?

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

Code P1166 Acura 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 P1166 Acura - Air/Fuel Ratio Sensor 1 Heater Circuit Malfunction - AutoCodes.com
P1166 Acura Code - Air/Fuel Ratio Sensor 1 Heater Circuit Malfunction

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