P2608: Intake Air Heater B Circuit High
What to do
Cold starting will be poorer and there will be more white smoke on a cold morning. Nothing here threatens the engine.
Ask for the heavy stud terminal on the heater itself to be checked and retightened before anything is bought. It sits on the inlet manifold, heats and cools thousands of times, and works loose — and because it looks like part of the manifold rather than part of the wiring, it is the connection people walk past.
If any work has recently been done on or around the inlet manifold, say so. That cable has to be moved to reach several things, and one left off or not properly tightened produces exactly this.
What this code means
The second intake air heater's control circuit reads above its valid range — an open circuit, a disconnected connector, or a short to supply.
An open circuit is the usual finding, and on this family it has a characteristic location: the heavy stud terminal on the heater itself. It sits on the intake manifold, is exposed to heat cycling and engine bay moisture, and is normally secured by a nut that relaxes slightly over years of expansion and contraction. A terminal that has worked loose arcs, corrodes and eventually opens — and it is the one connection on this circuit that nobody thinks to check because it looks like part of the manifold rather than part of a wiring loom.
A code appearing after work on the inlet manifold, the fuel filter or anything else that required that cable to be moved is a loose or unrefitted stud until proven otherwise, and retorquing it is the entire repair.
The consequence is the same as the rest of the family: worse cold starting, more smoke, rougher running until warm.
Likely causes
Start here
- Corroded or loose connector · easy
- Open circuit in heater wiring · moderate
- Failed intake air heater element · moderate
Less common
- Failed intake air heater relay · moderate
- Wiring shorted to voltage · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about P2608.