Technical Throttle control shorting error, multiecuscan

[andydiver]

Hi, my 2009 x250 2.3 throws an engine light every so often. Forgot to write the code down but is described as low reading on throttle control valve (short to ground in the explanation)
Happens every few hundred miles and self extinguishes the light after 5 clear runs.
Have checked the wiring route and connections under the passenger side light, had a good look about and no chaffing. I guess the throttle valve itself is between radiator and engine? No problem with how the van drives, this happens wet or dry. Is it worth digging deeper. .

 

[rolopolo]

I'd hazard a guess at needing a throttle control and loom if required, even if a Pierburg they go wrong still from water ingress or just clagged up with soot and gunge

 

[CDK]

If the valve got stuck in open or partly open position there would be more EGR related errors and you would have problems driving, so it probably is a partial short in the valve coil. The ECU detects an unusual high current, switches the warning light on and stores the code.
This is not a serious situation, but pay attention to the fuel consumption. I noted an increase of 10-15% when driving with the warning light on so I had no choice and had to go through the trouble of repairing the valve.

 

[PC Vehicle Movements]

I had this problem on my old van it turned out to be a broken wire in the loom from the throttle body

 

[andydiver]

I had this problem on my old van it turned out to be a broken wire in the loom from the throttle body

That's the kind of thing I am hoping. Need to put aside a day to have a good look but will put that off until that or some other reason forces the issue. . I infer that in the event the fault becomes persistent it will still get us home. Thanks for all of your responses

 

[PC Vehicle Movements]

the garage fitted a new throttle body but still not working it took them 10 mins to find the broken wire in the loom they just stripped it back out of the plastic casing and there was a load of green corrosion in one area so quite easy to find and repair

 

[andydiver]

So had a good look at this tonight and have found a failure point and fixed it I hope . Error code is P0638. It was getting a little worse with engine hesitation under load. There is a multi pin connection buried in the fuse box next to the air filter. The wires from the throttle valve buzz to there. The connection is likely to have sat in water over the years as is at bottom of plastic tray. Open up, find corrosion, scrubbed up and hopefully fixed. See pics. Likely a cause for other issues!!!
Had to follow the engine loom and it divides, one spur to a connection on the Ecu, the other spur loops round into the Base of that box and the connectors you see pulled up.

 

[andydiver]

This pic shows the pin making the bad connection buzzing though to the 4 pin connection on the throttle, grey wire.

 

[philgb]

Andy diver, quick question, how did you separate the blue/black connector block, struggling a bit and don't wish to break it! :bang:

 

[andydiver]

There was a blue part which wraps round the join line. It has a wedge action if you slide it to the side the connectors are prised open, opposite to close.

 

[philgb]

Thanks Andy diver, that worked a treat, the pins and sockets were all ok, cleaned them any way
Cheers

 

[andydiver]

No worries. Do you have an issue with the van or are you being pro-active? The loops of cables under the light in that area have been reported to have chaffing issues also.
Oh and the big connections to the Ecu next to that fuse box might also be worth opening for a look. The plastic lid / lever on the top of the connection lifts to prise them open once you have removed the splash cover

 

[philgb]

I have had the dreaded P0638 code for over 3 years in the camper. Thing is, it runs brilliant, fuel consumption is excellent, only noticeable thing is a slight hesitation in 4th gear when flooring the throttle, which I like to do now and then to clear the gunk out.
I do not want to spend hundreds of pounds on changing the throttle body unless I have to, that's why I followed your post.
I'l take the headlamp out and check for chaffing next.
my model is 2007 120 multijet 2.3
Thanks

 

[andydiver]

Yep, that's how mine was. Check the connection at the throttle body there is a short loom dropping from the long plastic wiring box at the front of the engine. I could just pull it out my hands are average size, you have to squeeze one side to release it.

 

[andydiver]

Update.... fiddling with the connection to the solenoid unit on the throttle body stopped the error for periods, then it comes back. Decided to fix once and for all. Not prepared to spend money, or take the front off to replace the whole unit, figured that the solenoid unit can be dropped off from underneath. Found the unit had too much water damage to feel comfortable to clean and put back. Found an old style replacement on ebay with the same throttle solenoid and have swapped it onto mine. I made up my own spade connections to it and potted them to avoid the now useless old connection.

 

[Johndw]

Hi Andydiver - I have a 2.3 Multijet based MH 2007 with only 22k miles. I have just done a 260 mile round trip ( first long run this year) and have been getting gross hesitation under power although tickover is fine. Tried full throttle and then zero throttle but it comes back after a short while. After this has happened and I stop for a road junction I can hear a pulsating/cycling noise in the back ground while the engine is ticking over. My local garage has suggested an air system clean but not sure if this will solve the problem. Any thoughts you have would be welcome. Thanks

 

[andydiver]

That is a similar symptom to mine when the throttle solenoid was dicky. In my case it would always throw a fault code and therefore the engine light would come on. Don't know if the unit can fail in a way not to throw a fault but is not unlikely. Does no harm to clean the wiring anyway you will see where in these pages and similar. If you can get the big black pipe off the throttle valve casting (right in front of the engine against the radiator) you can feel the big butterfly and check it springs open properly and without feeling restricted. Bugger to get off though, I cut the factory jubilee and put a new one on after. Oh and with multiecuscan you can run a specific test on it which might be revealing, well worth your own copy.

 

[adyjay33]

Hi, I know this is an old thread, but I have that yellow connector that is in one of your photos, and it is not connected to anything, do you know where it connects too please?
Thanks on advance.