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P0181 – What Does It Mean and How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


P0181 is an OBD-II Code that refers to Fuel Temperature Sensor A Circuit Range/Performance


A P0181 code is a general diagnostic trouble code that occurs when the ECM/PCM detects a problem with fuel temperature sensor ‘A’ circuit. It is generally a sign that the signal is out of specifications. This indicates that the sensor voltage fell below or went above calibrated limit specifications during the self-test.


Common causes for this code include:

  • Damaged wiring or connectors, or loose sensor connections
  • Open or short circuit in the sensor wiring
  • Fuel temperature sensor itself is defective
  • Bad intake air temperature sensor


The symptoms of a P0181 code are:


To diagnose a P0181 DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Visually inspect wiring, connectors, and the sensor itself for damage or loose connections.
  3. Check intake air temperature sensor operation
  4. Test fuel temperature sensor ‘A’ with a multimeter
  5. Compare the results to manufacturer specifications
  6. If necessary, replace the fuel temperature sensor
  7. Clear codes and test-drive the vehicle to see if the code returns

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P0181 code:

  • Not thoroughly inspecting all the wiring and connectors for damage
  • Not testing the sensor with a multimeter
  • Failing to clear the codes and test-drive the vehicle after repairs are completed

How serious is this?

A P0181 code is a somewhat serious code because it can cause the engine to run lean and produce less power. Additionally, it can lead to decreased fuel economy. If the code is not diagnosed and repaired in a timely manner, it may cause further damage to the engine.

What repairs can fix the code?

The following are solutions that may fix this problem:

  • Broken or faulty wirings must be repaired or replaced
  • Damaged connectors should be replaced
  • Loose sensor connections should be tightened
  • Fuel temperature sensor may need to be replaced
  • Intake air temperature sensor should be checked for proper operation

Related codes

A P0181 is related to and may be accompanied by the following codes:

P0180 – Fuel Temperature Sensor A Circuit

P0182 – Fuel Temperature Sensor B Circuit

P0183 – Fuel Temperature Sensor C Circuit

P0202 – Injector 2 Circuit

P0200 – Injector Circuit Malfunction


In conclusion, the P0181 code is a diagnostic trouble code that refers to a problem with the fuel temperature sensor A circuit. This code is a somewhat serious because it can cause the engine to run lean and produce less power. The most common cause for this code is damaged wiring or connectors, or loose sensor connections. To fix this problem, a technician would repair or replace broken or faulty wirings, replace damaged connectors, and/or tighten loose sensor connections. Additionally, the fuel temperature sensor may need to be replaced.