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Help! Do I Have An Ecu Problem?


Argee
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Hi Everyone!  Thanks in advance for your assistance.

 

I have a 2003 2.5 CRD Grand Voyager (Why oh why did they stop making manual transmission versions??)

 

I have had it for a while and have been living with the fact that neither the air conditioning or the seat heaters work.

 

Regarding the air conditioning:

 

I previously replaced the leaky heat exchanger and had the system recharged and investigated.  I was told that the radiator fans should come on when the a/c is engaged but they didn't.  I checked the a/c pressure transducer and all 3 of the radiator fan relays that the diesel version is blessed with but I could not find a fault and could only think that the ECU was not providing an appropriate ground signal to get the relays to function.

 

I recently completed a pretty long drive and got stuck in traffic for a while and it was a hot day.  The car started to 'pulse' at idle and I noticed that the temperature was creeping up above it's normally low value and that the exhaust had a whitish hue to it.  I put the internal heater on full blast and the temp came down a little.  I suppose, I shouldn't be surprised that the radiator fans did not come on when the engine was getting hot too.

 

When I got home I did some more reading of the service manual and found out about the ignition key method to display fault codes.  I got a P0403 code which means either an open or a short in the EGR solenoid circuit. With the help of the wiring diagrams, I tested the continuity from the Intelligent Power Module through to the connector that attaches to the ECU hoping to find a broken wire - but it was fine.....

I also took the opportunity to recheck the Radiator fan circuit and noted that the Rad Fan electric motors had a pretty high resistance.  Hoping that I had found my fault, I stripped down and overhauled the electric motors in the fans (ignoring the statements that there are no user serviceable items inside!)  When I refitted the fans.......they still didn't come on.....

 

Does it sound like I have an ECU problem?  Are there any places around that can test them?  I did call my local Chrysler dealership, which is a few miles away in Guildford - only to be told that they didn't have diagnostic kit for Chryslers of the age of mine!!  (I wasn't too impressed by that!)

 

I've seen a few ECUs for sale on ebay - one is the exact spec of mine.  Do these need to be programmed with VIN numbers and matched to key fobs?    

 

I did stumble across an article that said that some older ECU software versions did not allow enough time for the EGR solenoid to cycle and would throw up a fault.  

 

Should I expect to see a radiator fan fault code when I do the ignition key wiggling?

 

As if I haven't asked enough already, does anyone have a clue about the problem with the front seat heaters?  Again, the circuitry seems to be fine - could that be another dodge ground signal too?

 

All advice very gratefully received!

 

Argee

 

 

 

 

 

 

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I would go to a dealer and get them to operate fan(s) and EGR using diag equipment, at least that rules out the fans/circuit of they work, they can hire the older equipment. If they say they cant or give some excuse then go elsewhere because they clearly cant be bothered.

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Might sounds like a daft question, when you had the fans off/stripped down, did you apply 12v to them and see if they actually spun?

 

From all your diagnostics you sound like you're almost there. I'd be surprised if the ECU wasn't sending a trigger to them.

 

I've also not heard of the fans coming on when the air-con is engaged. I can't say I've ever seen mine on in that situation. (2005 2.8crd so a very close model to yours).

 

On the seat heaters, since circuit seems to be sound, i'd be suspecting the connectors under the seat as i've found these to rattle loose easily. Again, why not disconnect them and stick your multimeter on them when switched to 'on' and see if you get a voltage through which would check everything including the earth bonding to the seats?

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Thanks for the reply AndyB2000,

 

Might sounds like a daft question, when you had the fans off/stripped down, did you apply 12v to them and see if they actually spun?

 

From all your diagnostics you sound like you're almost there. I'd be surprised if the ECU wasn't sending a trigger to them.

 

I've also not heard of the fans coming on when the air-con is engaged. I can't say I've ever seen mine on in that situation. (2005 2.8crd so a very close model to yours).

 

On the seat heaters, since circuit seems to be sound, i'd be suspecting the connectors under the seat as i've found these to rattle loose easily. Again, why not disconnect them and stick your multimeter on them when switched to 'on' and see if you get a voltage through which would check everything including the earth bonding to the seats?

 

I have to admit that I didn't actually put 12V across the fans....  I measured the resistance across each of the coils before and after I cleaned up all the brushes and commutator and they went from up to 380 Ohms down to low single digits.  I did notice that there were a couple of inductors and a capacitor next to the brushes, which I would think are to change the phase of the signal.......hmmm....that's now got me thinking.....they would surely only change the phase of an alternating current - I wonder if someone might have put the fans from a petrol variant into my diesel.....   From what I've read, the petrol fans get a variable pulse width signal from the fan controller, whereas the diesel fans either run in parallel or in series as a way of changing fan speed....   Does that sound right?  I think I do need to hook up 12V to them to see if they run or not.

 

I was told that the fans should come on when the a/c is engaged to help the cooling cycle....perhaps that's not right then... I wonder if I've got a dodgy compressor.

 

I will try to find the seat heater connectors and check them out.

 

Many thanks for the help :-)

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Hi Argee,

 

Good call on the 12v (and also interesting point on the petrol v diesel, good thinking as I've seen this also and it has puzzled me many times before!) to the fans, so we know the fans themselves spin.

I'm going to test the theory later on when aircon is switched on and cooling if the fans should come on, so will post back to compare notes then.

 

So now it's back to wiring looms and potential ECU. Trick is, forcing the fans to come on, as without triggering the circuit for 'fans turn on' you can't be sure when testing. You've also tested the relays I see, when you say tested, continuity ok and when energised with 12v they throw over and continuity good (am wondering if they've arced too much and won't carry a good current). In fact, there is probably a way to jumper the relay in the fusebox to give it 12v to force it to throw over and go on.

BUT, I'm not 100% on that, I'd have to do a bit of reading of the wiring diagram to make sure it won't fry things, so for now maybe take a look yourself, see what you think and I'll do a little reading and see what I can find.

(I do know you can force the air con clutch relay manually using a wire jumper, as I've done that in the past. Assumption is the same!)

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Aha, I've found a youtube video on this, which I suspect some of your info might have come from:

https://www.youtube.com/watch?v=AdIYm9kM5E0

 

That refers to an older model though, 1997 and he states in the video that he can turn the air con on to force the fans to run (that way testing the sense pin on the solid state relay in that case).

However a lot of the detail in that video is also reproduced here:

http://www.supremepundit.com/2013/12/how-to-fix-a-radiator-control-module-of-a-dodge-gland-caravan-2000-1999-1998-1997-1996-2001-2002-2003-2004/

 

Which includes your model I believe in the 2003-range. In the diagnostic images just before half way down the page it has information on testing, step 5 is the one I was referring to which is testing by jumpering the relay signal wire, however I'm not 100% on that element (and don't want a fried ECU!).

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Hi Argee,

 

Just travelled home and checked my 2005 model 2.8CRD auto, engine idling (temperature gauge just below half after a 20 min drive as usual) and coolant fans weren't on (expected).

Turned aircon down to LO and forced aircon on (star symbol) and after a minute both coolant fans do indeed come on. Turn aircon back up to normal temperature and after a minute the fans turn back off, so you are indeed correct that the aircon causes the fans to switch on.

 

So I stand corrected, when aircon is switched on the coolant fans do indeed get triggered, so at least you have a positive way of testing the system out, so now you can check the trigger to the relay to see if it's getting the signal to switch the fans on, etc. (And don't need to try the jumpering method I mentioned either)

 

Hope that helps a tiny bit more.

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Thanks andyb2000 for the video! I think the vehicle he was working on was (not surprisingly for the US) a petrol version which has the single rad-fan relay mounted low down inside the engine compartment. My diesel has 3 separate relays mounted just below bonnet level at the right side of the engine compartment.

I took my Chrysler to a dealer yesterday for them to hook up some proper diagnostics. I'll fond out the deal (and the cost!!) in a few days and let you know. I'm hoping it's something really simple that I've missed!

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Update!

Last year I finally got a 'report' from the main dealer.... On the fan issue, I was told that the air con compressor was not putting out enough pressure to trigger the ECU to activate the fans.... I still haven't sorted that out as I had other issues. The car wad putting out a lit of white smoke, and they said that it was not economical to repair. They also said that it had sn oil leak and offered to steam clean the engine to help identify the source.

I decided to pay the £60 charge for steam cleaning. As it turns out, they charged me to just wipe off the bottom of the sump and didn't clean else..... I must add that they didn't charge for any of the in-depth diagnosis.

When I finally got the old Smokey girl home, I started reading up and doing my own diagnoses.

I found that the exhaust was really hot. That led to me discovering that the vacuum hose to the EGR valve had deteriorated. About 20p fixed that and returned the exhaust temperature to normal......but it was still smokey.

Next was to get the injectors out and tested. I took them to a diesel specialists and found out that they were way out of tolerance and putting out far too much fuel... Being hopeful I splashed out around £500 for a set of refurbished and adjusted injectors. This made the engine run much more smoothly, and with a little less smoke....but still enough to provide visual cover for a battalion of infantry!!

After talking to a work colleague, my next investigation was the turbo... I picked up a cheap pc boroscope and found lots of oily gunge on the intercooler side of the turbo.

A couple of weekends of work produced a very oily turbo. I picked up a refurb kit for around £50 and then the same company had a rotor balance service for £50. After another weekend's work I got it all back in and....hardly any smoke!!! ? Even less as it burned off.

Of course then I noticed that I had some welding to do to both rear sills...

..and....last week it passed an MoT and is now back on the road! ? Very satisfying?

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