2004 MDX problems - VTM-4/check engine
 

My mother's 2004 MDX started having some problems. It has 112K on it and the 105K service has been done.

Yesterday, while driving the VTM-4 light came on and check engine light. My mom pulled over right away, shut off the truck and restarted. The VTM-4 light went off and check engine light stayed on. We scanned the code today and it says it's misfiring in 5 cylinders.

I don't understand how the two are connected, maybe it's an electrical issue?

There have been some tough starts in the past, even before the 105K service when you start the truck in the morning, put it in reverse and it almost dies.

Have any of you had this issue before? The truck has been maintained to the T and is in very good shape. We've had it since 81K and have never had a problem.

Thats strange. Maybe a fuel issue? No idea how the VTM could be connected to that though.

That's the thing is that I don't see the two being connected at all.



Now the CEL went off by itself today. :wtf: I don't understand what's going on.

After doing some research online, I found that this may be a EGR problem. I'm really surprised that this would be it but sounds like it's a very common problem with MDX and that Acura actually extended the warranty on MDX EGR valves to 8/80K - if you are under 80K, I'd go in and have them replace it.

Might order one tonight, still hoping for the CEL to come back on so I can scan it again.

Sounds like it could be the egr / pcv valve. You should order a new pcv valve & reuse the egr valve, soak it in some dissolvent like seafoam to loosen up the gunk.. but you'll definitely need to pick that crap out though. :yuck:

I'm really hoping it is the EGR.

I don't have much time to mess w/it right now, been busy. I'm also hoping the CEL will come back on soon :rant:

Changed out the EGR valve and the truck is still having a misfire. I called a Honda shop by my house and they said that it needs a valve adjustment and need to clean out the throddle and egr port.

I'm thinking of taking it to them, I need to get this figured out.

when you replaced the valve, did you clean the port aswell?
if not then do so.

The VTM is usually unrelated. This will accompany alot of CEL codes, but means nothing. I think its a safe mode. With that much misfire, valve adjustment sounds right. Usually EGR is the main culprit, but you changed that.

Just picked the truck up from getting the valves adjusted and had them clean the EGR port while they were at it. So far, runs much better. I will report back on any MPG change.

I have a similar problem with my 2005. This past weekend, we had the timing belt replaced (we're at 110k miles). Didn't notice any immediate problems Sunday in the limited driving we did. Monday, my wife tells me that it feels like the transmission might be slipping? She said it did it one time Monday and one time Tuesday. Yesterday, she calls and tells me that the VTM4 light and the Malfunction Indicator Lamp came on while she was driving. She parked it while she ran errands with a friend, then came back to it and took it home. The VTM light went out but the MIL stayed on. I drove it a little yesterday and never noticed the "slipping" she mentioned, but the MIL stayed on. The manual says it could be a gas cap that was loose, so I tightened that, or it could be some emissions codes were lost because they unhooked the battery during the timing belt replacement to replace the water pump while they were in there.

We've had zero problems with anything since we got it a year ago, and as soon as the timing belt is changed, we have these weird problems. Anyone have any thoughts on this?

Thanks!

Update. My dad took the MDX to work this morning and averaged 24.3mpg (all hwy). This truck has never seen anything even close and it runs much better than it did before.

Trlblzr, this is EXACTLY what happened to ours. We even got the timing belt/water pump done right before it happened also by a family mechanic. Did you do it at the dealer?

Have you had the valves adjusted?

I spoke with the mechanic last night about it and he said the truck was running very lean (.81 or so) and is now around 1.00. I can honestly say I see a major difference in how it starts and drives. We were at the point that sometimes on cold mornings, we'd start the truck, put it in reverse and it would almost die.

Oh and BTW. I called Acura, they wanted $450 for valve adjustment. I had my local Honda shop do it, they charged $240 for valve adjustment and to clean the EGR port.

If anyone lives around here, I STRONGLY recommend this shop. I take my TL and RL there as well. They will only work on Honda's.

Nope, we haven't done that in the year we've owned it. Ours was done by a family mechanic, not our regular mechanic. Our regular one is a former Honda Certified Tech from one of the local dealers, but he was just a little too expensive on the belt replacement. I'll ask him about the valve adjustment. Did that get rid of your warning lights and all?

The warning lights were cleared months ago and never came back on. My dad forgot to write down the codes :doh: and I didn't know what was wrong with their car. First we tried the EGR valve and that didn't do much (common problem anyways and it was $80 to replace - no big deal).
There were no CEL light or any codes present but you could feel the motor not running right, it had some hesitation and a little shake to it. Looks like it may be gone now with the valve adjustment.

I believe valve adjustment is part of the 105K service. Anyone know?

Nope, in fact I don't believe a valve adjustment has a service interval, it's an as needed service. Typically a new engine will break in early and a valve adjustment is done to spec in the valves (typically the exhaust valves) within 15k miles. That was a great price for a valve adjustment.. it's not difficult but it takes time.. your mechanic is dirt cheap compared to most shops.

The 105k service should include timing belt service, drivebelts, plugs, pcv valve, refill coolant... maybe some other fluid replacements as well.



Did you get the plugs changed as well and adjust the PCV valve or replace it all together? I'd pull any DTC's you have and get the timing checked to make sure it's in spec before considering a valve adjustment.

Also when you describe slipping, do you mean as a transmission where it will rev excessively before shifting or something more along the lines of power loss / low rpm?

Nope, not yet. The rest of the 105k is coming shortly. We just had an opportunity for the timing belt and took it :-)

Sounds like the "slipping" she's describing is more like power loss @ low RPMs. I haven't had the problem when driving it. We had our mechanic pull the codes last night and had misfires in a couple cylinders showing. Going to get those looked at tomorrow and see what's going on.

It might be misfires that are plaguing you which can be egr or pcv valve related or it very well could be the exhaust valves. I would first verify your timing with a reader, if it's okay, remove your egr valve and clean it up. Give it a soak and scrub in some seafoam and clean the exhaust inlet port with some deep creep.. Then I would buy a new pcv valve and replace that as well. See if it runs better after the treatment and before replacing the plugs.

If it's a no go.. take the plugs out and do a leakdown / compression test to look for issues.. if that looks okay then go ahead and replace the plugs, be careful with the coil packs, make sure you seat them over the plug correctly (it shouldn't push back much, it's a spring trigger) and don't use dielectric grease. It sucks to not be running well but I'm sure you'll be able to find the culprit. Worst case, timing is off and you bent some exhaust valves, or you need a valve adjustment. GL bud.. :xfingers: it's a cheap & easy fix.

Thanks for your help! I'll give those a go :)

Jason

I remember when my dad took it to get scanned, his was showing multiple cylinders misfiring as well. I believe it was 5/6...

Good luck.

holy crap. this happened to my 03 (128k) this weekend. CEL and VTM lights came on outta no where. Shut the car off then turned it on, and the CEL stayed on. I got a master tech that works on my car on the side, taking my car to him this week to see what he says. I will report back if I got the same problem as you.

Let us know what the code is. Have you ever changed out your EGR Valve?

looks like our code is P0339 Cam & Crankshaft Sensor... either our sensor went bad or it got knocked outta whack while the timing belt was being replaced. anyone have experience with that?

and of course after I made my original post, the CEL light went off.. wtf?! lol

^Ours never came back on either but the truck runs noticeably different and much better might I add :thumbsup:

Thanks for the info everyone. I'm in the midst of buying an 06 MDX with 80k miles on it. The truck looks MINT & drives great but of course the 80k scares me some.

We have two MDX's in the family, bought both of them from Honda finance with 80K on them. One's an 03 and one's an 04. I wouldn't be too worried about the mileage as long as it's in good shape and maintenance has been kept up.

^ too bad it sold, we snoozed. Guess it wasnt meant to be but it was CLEAN. The search continues, I think we are liking the black with the darker tan interior.

Ok, my CEL/VTM-4 lights has been coming on for the past month now. The consensus in this thread points to the EGR valve.
Well, I installed a new EGR valve this past weekend, but the lights still come on!

What else could be the cause? I don't have a code reader. My regular mechanic charged me $40 3 weeks ago, to diagnose said problem!

The truck runs fine(with the light on). And I actually get better gas milage, since the truck only operates in FWD mode whenever the VTM-4 light is on, lol!

Both lights are still on?

Yup!

I disconnected the battery to clear the CEL, but a few minutes after I started driving, it came back on.

Did you clean the EGR port when you changed the valve?

I sprayed some carb cleaner in there. Maybe I didn't clean it good enough?

What's the best way to clean it?

Hey Vas25TL, I see you are in Milwaukee area. I have an '05 MDX that has exactly the symptoms you described earlier. VTM and Check Engine both on, occasionally the VTM will go off. I replaced all the plugs because the vehicle failed emissions test and codes were misfires in 5 out of 6 cylinders. What Honda dealer did you take your vehicle to for service? Wilde?

I took it to Car-isma motors.

Check them out, they're in Cedarburg. They are an independent shop that ONLY works on Honda's. They won't even touch a Passport since it's made by Isuzu.

I had my valve job done by them, $150 less than dealer wanted. They have been in business for quite some time, use only Honda Genuine parts and is ran by a father/sun and a team of techs.

http://car-ismamotors.com/


I take all my cars there...they are the most honest shop I've ever taken anything go. I took my older TL there for a ball joint squeak once. Any dealer would have sold me on a new ball joint. They took a syringe and put some oil in there. It's been 8 months, not a squeak out of it...

Thank you guys for the feedback on this thread. I've been chasing this one forever and couldn't figure it out. The misfire codes started to support the valve adjustment as the culprit. I once had an S2000 with bent valves and that code kept coming up.

MDX runs so much smoother now, more MPG, more power, super quiet at idle, does not die when cold. It wasn't the EGR, dirty throttle body, bad MAP sensor, binding pulley, or any of that, it was simply the valves needing adjustment. All but one lifter was out of spec.

I took it to a shop here in San Diego 858-558-8808 and got it fixed right away without being run around with all the lame band-aids mentioned above. They found that the idle was super low 500 RPM instead of around 750. I said no, to another shop that wanted me to get the throttle body recalibrated or replaced & EGR replaced $1000.I had to get it dropped off overnight because the guy was anal about it being dead cold when the adjustment was done. Intake manifold & valve cover gaskets were changed, which added costs, but eliminated chances of leaks later.

I had a weird binding sound when starting the car, and it wasn't a pulley but came down to the starter not retracting completely, they took it out, cleaned it, re-lubed & voila!

Thanks again VAS

Ok, I took the MDX to my mechanic and the CEL shows a P0325 code(knock sensor 1 curcuit).

I googled that(a few minutes ago) and found out that there seems to be a problem with the insullation that covers the wire for the connector that goes to the knock sensor. Whatever material the insullation is made of, seem to attract rodents! I read stories of rats chewing through the wiring harness!

While replacing the EGR valve(to no avail), I did notice rat(not mice, lol....I live in the urban jungle) poop on the battery, and hair on the intake manifold cover!!

It seems I'm gonna have to replace both the sensor and the wire connector. Or, should I just replace the wire connector? After all, the CEL did come on a few minutes after I started the truck early one morning. So obviously, a rat must have feasted the night before!

just replace the wire / connector.. no need to replace the sensor

Yep, just as I thought!

Took the X in yesterday, and told my mechanic that I thought a rat must have chewed the wire that connects the knock sensor to the wiring harness. I brought a new sensor, (cause I figure I might as well just change it even if it was only the wire being chewed off) cause it's a big job to get to the sensor. Don't want to pay twice for taking stuff apart!

When I went to pick up the X today, the mechanic told me that the wire was indeed chewed up and part of the connector(part that's fused to the sensor) too!! He said it must have been a really big rat, lol, for it to be able to chew up the hard plastic connector part!

Well, drove for a hour and everything's all good now! No CEL!

Where is the knock sensor and the EGR...are they a hard to find or difficult to access?

I have an 04 MDX Navi/RES

Thanks