Honda Pilot Diagnostic Code

re 2004

Engine was replaced [no VIN available] 3 mos ago. All ok, runs great but engine light on and get code VTM-4.

Initially there were several other codes [I guess motor replacement is like surgery] with eng light, but mechanic fixed everything, except this persistent VTM-4. Haven’t asked him about this code yet. What’s happening? Thanx.

The VTM system on that vehicle is the traction control, and like on other vehicles, it is disabled when the onboard computer detects an engine problem. Some people have fixed it by cleaning or replacing the EGR valve, but there are other engine-related issues that will also cause problems with the engine’s performance and will disable the VTM.

This is something that you should get fixed before the winter, when you might need the traction control.

What are other more common engine-related issues which can disable the VTM?

Anything that causes the engine to run less-than-optimally can disable systems like traction control, vehicle dynamics control, and even cruise control. The list of problems that can cause an engine to run less-than-optimally is…very long…but some prime suspects would be old spark plugs, a bad ignition coil, bad sensors in various areas, and…believe it or not…even something like a bad purge valve in the evaporative emissions system.

OK. Thanx!

Another idea, maybe everything about the engine is ok but there’s a computer/sensor compatibility problem with the new engine installed in the old car. I guess if I had this problem I’d phone up one of the companies that repair ECM modules. They might be able to offer some advice. Being in the module repair business ever day, they know more about the subject of electronic compatibility problems than pretty much anyone else.

Interesting Geo.

There is no check engine code VTM-4. Could the VTM button be stuck ot something keeping it powered so that the button stays lit? Or with the unknown mileage, unknown condition of this vehicle just maybe there is actually a problem with the VTM that the mechanic does not know how to deal with?

This is a classic example of why engine swaps are very rarely done anymore…To be successful, the ECM for the donor engine stays with the engine and must be swapped too, if it’s possible to do that…

Actually, engine swaps seem to be quite common as mechanics don’t want to do rebuilds anymore. Blown head gasket? $3000 for a head gasket repair, or $1500 for a used engine swap. And, I guarantee they don’t swap ECMs when they do. The key is to swap the sensors to maintain compatibility.

No matter how carefully done, there always seems to be some little incompatibility that results in a CEL that refuses to behave…The kiss of death if you live in an emissions control area…

@Caddyman . . .

It’s not always possible to keep the ECM with the donor engine, at least not on recent model cars

The ECM is often “married” to the car, through software. While it’s possible to swap an engine from car to car, it’s not always possible to swap the ECM from car to car

I’m only a sample of one, but the used engine swap in my Compass last year went just fine. One pulley that came with the new engine was out of alignment, but replacing it with the old one made everything line up. Electronically, there was never a problem.

For 500 miles the check eng lite is on, car runs like a top, and there’s an intermittent lite (3 inches away from the check eng lite; a round dime-size amber lite in the dash area in front of the wheel) and it reads exactly: VTM-4. The green lite on the VTM button used to activate the VTM gear-shifting is not on, and while running at 5mph trying this button appeared to do nothing.