Powertrain, generic (extended)

P2607 Intake Air Heater B Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2607 says the signal from the circuit of intake air heater B stays too low, which normally means a grounded control or feedback line, or a relay output pulled down. No manufacturer documents P2607 publicly. The closest published equivalents are Deutz, whose MD1 code list files an under-voltage or ground short at the preheating relay of heater A as P0541, and Volvo, whose 2020 engine software list contains the low-side code P2CE3-11 for heater C but none for B. CARB asks for the heater circuit to be monitored for current and voltage drop, which is how such a low reading becomes visible. P2608 is the high-side counterpart, P2605 the open circuit, P2606 the plausibility check. With heater B unusable, cold starts take longer and the engine smokes white at first.

Likely causes

Control or feedback wire chafed through to ground
Internal short in the preheat relay
Moisture or corrosion in a connector of the heater circuit

Symptoms

  • Hard starting in cold weather
  • White smoke after a cold start
  • MIL on

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–600
Time0.5–3 h

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

Parts involved

intake air heater bheater relaywiring harness

Related codes

P2605P2606P2608P0541P2CE3

References: law.cornell.edu, serdia.deutz.com, static.nhtsa.gov.