P2605 code meaning
Intake Air Heater B Circuit/Open
Powertrain system Generic code P26xx codes Check engine light
What P2605 means
P2605 points to an open circuit at intake air heater B, a second heating element in the intake of a diesel engine; the control unit finds no current path through the element, its relay or the cabling. Volvo's EMS code lists keep heaters A, B and C apart. An August 2020 Volvo software change log for heavy-truck engines names P2605-13 among the codes tied to a preheater relay robustness problem, and a 2022 Volvo/Mack instruction for 11 L and 13 L engines asks for terminal tension checks at element and relay and a software check before relay and supply cable are renewed together. CARB expects intake air heater circuits to be watched for current and voltage drop. P0543 is the open-circuit code of heater A, P2CE1 that of heater C. Harder cold starts and white smoke follow.
P2605 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2605
- Hard starting in cold weather
- White smoke after a cold start
- MIL on
Common causes of P2605
- Most likelyLoose, corroded or burnt terminal at heater element or relay
- PossiblePreheat relay no longer switching
- PossibleHeater element B burnt through
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Intake air heater bHeater relayWiring harness
What each part of P2605 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 6 | Area: computer (engine control module) and output circuits. |
| 05 | The exact fault in that area. |
What to do next
- Note P2605 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2605
What does P2605 mean?
P2605 means "Intake Air Heater B Circuit/Open". P2605 points to an open circuit at intake air heater B, a second heating element in the intake of a diesel engine; the control unit finds no current path through the element, its relay or the cabling. It is a generic code, so it means the same on every make.
Is it safe to drive with P2605?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2605 fail an emissions test?
Yes, it can. P2605 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2605 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P2605 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.