P0540 — Intake Air Heater Circuit Fault
What it means: Intake Air Heater Circuit Fault.
How serious / can you keep driving: Serious. Power derate likely — plan to stop soon.
Check first: Check intake air heater fuses
Don't risk it — look up listed providers near you and give them this code when you call.
Listed providers nearest Oklahoma City, OK
Closest first. Tell them P0540 and what the truck is doing. RoadService.app lists these providers and does not employ them or carry out the repair.
- 0.0 mi away — based in Oklahoma City, OK · (405) 551-3320
- 0.0 mi away — based in Oklahoma City, OK · (405) 682-1362
- 0.0 mi away — based in Oklahoma City, OK · (405) 632-6010
Seen on: Heavy Truck/Diesel
What P0540 means
Intake Air Heater Circuit Fault. Common causes: Intake heater circuit fault.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- Intake heater circuit fault
- Failed grid heater
- open circuit
- fuse blown
First moves (roadside)
- Check intake air heater fuses
- test grid heater resistance
- replace if open
FAQ
Intake Air Heater Circuit Fault. Common causes: Intake heater circuit fault.
Serious — Power derate likely — plan to stop soon.
The most common cause is: Intake heater circuit fault. Other possibilities include Failed grid heater; open circuit; fuse blown.
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside P0540, or share the same subsystem.
- Engine Protection — Power Derate Active (SPN 1569 FMI 31)
- Intake Manifold (Charge Air) Temp — High (SPN 105 FMI 0)
- Turbo Boost Pressure — High / Overboost (SPN 1127 FMI 16)
- Boost pressure high (SPN 102 FMI 0)
- Boost sensor — voltage low (SPN 102 FMI 4)
- Intake manifold temp — voltage high (SPN 105 FMI 3)
- Intake manifold temp — voltage low (SPN 105 FMI 4)
- Injection control pressure low (HEUI — older engines) (SPN 164 FMI 1)
Same symptom: Won't start or won't crank
Other codes that end in a truck that will not light off, especially cold.
- Intake air heater voltage high (SPN 729 FMI 3) · Engine
- Crankshaft/Camshaft Correlation Bank 1 Sensor A (P0016) · Engine
- Glow Plug/Heater Circuit A (P0380) · Engine
- Intake Air Heater Circuit Low (P0541) · Engine
- Intake Air Heater Circuit High (P0542) · Engine
- Battery voltage low during crank (SPN 168 FMI 17) · Electrical, Charging & Network
Find a mechanic or related guides
General diagnostic guidance for diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.