What is P0540 fault code and what does it mean? What is the description of Intake Air Heater “A” Circuit Malfunction? How can you fix the fault code P0540? What are the symptoms and causes for the P0540 fault code
What is the P0540 fault code? What does it all mean?
If the powertrain controller module (PCM), detects that voltage signal from intake air heater “A”, circuit is not matching manufacturer’s parameters, then P0540 is set. This means that the voltage signal is either too high or too low.
An intake air heater system typically includes a heating element, fan motor to heat the engine, a temperature sensor and relay. To direct hot air to the intake, air ducts are also required. The intake air heater’s job is to heat the air that has been drawn into the engine during cold starts. Although they have different designs, it serves the same purpose. Because the hot mixture of fuel and air burns more efficiently than the cold, the volume of heated air drops. This reduces vehicle fuel consumption and therefore lowers emissions. The heating system only operates when the ambient temperature falls below the manufacturer’s set point.
The heating of the intake air is not possible in every vehicle. To compensate for the lower air density, these vehicles send additional fuel. This leads to increased fuel consumption and emissions.
Note: Fault codes marked “Circuit Fault”, indicate faults in the circuit, not the component. Sometimes, simply replacing components or sensors may not be enough to fix the problem. This separation of circuit and component reduces the number of possible causes, making fault finding much easier.
P0540 fault codes can be found on many vehicles, including, but not limited, to Chevrolet, GMC and Chrysler models as well as Ford, Mini-Dow, Dodge, Honda, Ford, Mini-Dow, and Nissan.
What causes the P0540 Fault code?
This code is usually caused by the IAT sensor not being properly connected after the filter has been replaced or removed for repairs. Before replacing any part, make sure to inspect the sensor.
These are the most common reasons that P0540 codes are triggered:
- – Defective heater relay
- – Shorted, damaged, melted, or ruptured wires to the heater “A” circuit. Or loose, corroded connections
- – Molten, burned electrical components around the heater
- – Heating element defect
- – Defective fan motor
- – Air ducts that are damaged or blocked
- Sensor for defective intake air temperature (IAT).
- IAT sensor-related cable and/or connector issues
- – The PCM is not working correctly or needs to be reprogrammed. This happens very rarely.
What are the symptoms of P0540 malfunction code?
Code P0540 is usually not accompanied by any symptoms. Severe symptoms that can affect vehicle driving are rare. You may experience different issues at sub-zero temperatures.
You may experience the following symptoms if your vehicle has the code P0540:
- – Illumination for the check engine light
- – Longer cranking time
- – Increased idle speed or stalling after the engine has cooled.
- – A slight rise in fuel consumption
- – IAT sensor fault codes can be set
How do I fix the P0540 fault code?
Before diagnosing P0540, it is important to inspect all wires, relays, or electrical components connecting to the heater. It is important to clear any codes and then test the vehicle again to verify if the code returns. If the code is not responding, it’s most likely due to the temperature (IAT), or the intake air heater.
Some repairs that could resolve the P0540 fault code are:
- Repairing a damaged heater relay
- – Replacing damaged or melted connectors, wires, and other electrical components to the heater/IAT sensor that are causing a short circuit
- – Replacing an inefficient intake air heater
- – Replacing an inoperative intake air temperature sensor
- – Replacing the damaged fan motor
- – Repair and replacement of restricted or damaged air ducts
- – Reprogramming or replacement of a faulty PCM
How Serious Is the P0540 Fault Code
Even if the code does not indicate any danger to driving safety, it is a serious problem and must be fixed. The vehicle could experience an increase in fuel consumption or a decrease of engine performance if the problem is not fixed. The engine may not start in extreme cold. Inefficient combustion of fuel can lead to excessive carbon buildup. It is best to have the problem diagnosed promptly and fixed as soon as possible.
