P0540
Intake Air Heater Feedback Circuit
Generic code
Vehicle Speed and Idle Control System
High severity
Hard repair
Free on OBD DashX
Want real-world data on P0540?
See which problems come with P0540, how often it shows up in other vehicles, and how to fix it — step by step.
- Real-world fix data
- How often it happens
- Step-by-step repairs
What P0540 means
- The fault code P0540 indicates that there is an issue with the circuit that controls the intake air heater for bank A. This may cause issues with starting the engine, reduced engine power, or poor fuel economy.
Possible symptoms
- Difficulty starting the engine in cold weather
- Reduced engine power or acceleration
- Poor fuel economy
- Illuminated check engine light
Possible causes
- Failed intake air heater relay
- Faulty wiring or connections in the circuit
- Loose or corroded electrical connections
- Failed intake air temperature (IAT) sensor
Related parts
- Air Heater: Air heater warms the incoming air if it is cold. Problems lead to poor fuel economy
Possible solutions
- Replace the intake air heater relay
- Check and repair any damaged wiring or connections
- Tighten or clean any loose or corroded electrical connections
- Replace the intake air temperature (IAT) sensor if necessary
Free on OBD DashX
P0540 on OBD DashX
Real-world causes, how often this code shows up, and the fix — step by step.
Open P0540 No sign-up needed · available in 10 languagesScan your own car
Read and clear fault codes, live data and service resets with the CaRPM app.