P0111, P0112, P0113, P0114 | Air Temperature Sensor (Signal, Low Out/High Out) |
If you own a Land Rover, you might have encountered one of these OBD codes: P0111, P0112, P0113, or P0114. These codes indicate a problem with the intake air temperature (IAT) sensor or its circuit. In this blog post, we will explain what these codes mean, what are the possible causes and symptoms, and how to diagnose and fix them.
What is the IAT sensor and what does it do?
The IAT sensor is a device that measures the temperature of the air entering the engine. The engine control module (ECM) uses this information to adjust the fuel injection and ignition timing for optimal performance and emissions. The IAT sensor is usually located in the air intake duct or in the mass air flow (MAF) sensor housing.
The IAT sensor is a thermistor, which means its resistance changes according to the temperature. The ECM sends a 5-volt reference signal to the sensor and monitors the voltage drop across it. The higher the temperature, the lower the resistance and the higher the voltage. The lower the temperature, the higher the resistance and the lower the voltage.
What are the OBD codes related to the IAT sensor?
There are four common OBD codes related to the IAT sensor:
- P0111: IAT Sensor Circuit Range/Performance Problem
- P0112: IAT Sensor Circuit Low Input
- P0113: IAT Sensor Circuit High Input
- P0114: IAT Sensor Circuit Intermittent
These codes indicate that the ECM has detected a signal from the IAT sensor that is either out of range, too low, too high, or erratic. This could be caused by a faulty sensor, a wiring problem, a bad connection, or a defective ECM.
What are the symptoms of these codes?
The most obvious symptom of these codes is the illumination of the check engine light on your dashboard. Depending on the severity of the problem, you may also experience some of these symptoms:
- Difficulty starting the engine in cold weather
- Poor fuel economy
- Reduced engine power
- Rough idle or stalling
- Engine pinging or knocking
- Black smoke from the exhaust
How to diagnose and fix these codes?
To diagnose and fix these codes, you will need a scan tool, a multimeter, and a wiring diagram. Here are some steps you can follow:
1. Scan your vehicle with a scan tool and record the freeze frame data. This will help you identify when and under what conditions the code was set.
2. Clear the codes and test drive your vehicle to see if they come back. If they don't, it could be an intermittent problem that is hard to reproduce.
3. Locate the IAT sensor and inspect its wiring and connector for any signs of damage, corrosion, or loose connection. Repair or replace as needed.
4. Disconnect the IAT sensor connector and measure its resistance with a multimeter. Compare your reading with the specifications for your vehicle. If the resistance is out of range, replace the sensor.
5. If the resistance is within range, reconnect the sensor and measure its voltage with a multimeter while backprobing its signal wire. Compare your reading with the specifications for your vehicle. If the voltage is out of range, check for any short or open circuits in the wiring between the sensor and the ECM. Repair or replace as needed.
6. If the voltage is within range, check for any other codes related to the MAF sensor or other sensors in the intake system. If present, diagnose and fix them first.
7. If no other codes are present, suspect a faulty ECM and have it tested by a professional.
Conclusion
The IAT sensor is an important component of your Land Rover's engine management system. It helps optimize your engine's performance and emissions by measuring the temperature of the air entering it. If you have any of these OBD codes: P0111, P0112, P0113, or P0114, it means that there is a problem with your IAT sensor or its circuit. You should diagnose and fix this problem as soon as possible to avoid further damage to your engine.
