Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P0541 Intake Air Heater A Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

Some diesels – typically Cummins engines in Ram pick-ups and commercial vehicles, and Iveco – heat the intake air with a grid heater in the intake manifold instead of or alongside glow plugs. It draws very high current through a relay (on recent Ram a solid-state relay) and is switched by the engine module before and after starting; CARB requires cold-start aids to be monitored. Cummins checks it by the manifold temperature rise, Iveco by the battery voltage dip when the relay switches. P0541 means the voltage in the monitored circuit stays too low – typically a control line or relay coil shorted to ground or open, so the relay does not switch and there is no preheating. No manufacturer document available to us uses this code; GM's Duramax LML has an intake heater but reports it under its own codes P154A–P154D.

Likely causes

Relay control line shorted to ground (chafing)
Relay coil open or solid-state relay faulty
Connector at relay or module corroded
Engine module driver

Symptoms

  • Check engine light on
  • Hard start in the cold
  • White smoke after cold start

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–400
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

intake air heaterheater relayheater wiringengine control module

Related codes

P0540P0542P0543P2607P2609

References: patents.google.com, patents.google.com, gsi.ext.gm.com, static.nhtsa.gov.