Caddy Max 2.0 140 No Communication with ECU

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Dave c
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Caddy Max 2.0 140 No Communication with ECU

Post by Dave c » Tue Oct 08, 2019 12:14 pm

Can anybody out there help me? 2011 Caddy started off 6 months ago when the exclamation mark came on and the cruise control was not working, when the vehicle stopped it would clear itself and would happen now and again, then I had an issue of the ABS light coming on ESP light coming on and I took it to my local garage and had it cleared.
A week or so later all the lights came back on including the yellow steering light again I had this cleared and the van was working fine again for a couple of weeks. I then went to start the van one day and it came up with the Button for Driver Assistant System Defective and Error Brake, it has been plugged in cleared again and it was all working fine then after another week all the lights came back on with all the errors and with the red steering light on the VAG will not communicate with the ECU it was never a problem when the steering light was yellow, we did get info off the VAG saying Failure to ABS module and lost communication with clusters so I went for replacing the ABS module first this then put all the lights out and the vehicle drove for about an hour before they all came on again.
So I sent the clusters off to be tested and it came back ok, as I started looking elsewhere ie wiring loom, fuses, relays, battery voltage I did lose the clusters, they went totally blank, I sent them off again and this time they came back saying they were non repairable so I bought new clusters & put them on, all dash lights are working but the fault lights are still there along with the annoying red steering light. I have had 4 different diagnostic checks now and we could not code the new clusters as we can not get into the ECU, so to bite the bullet I took it into VW but even they could not get into it! They suggested 4 hours labour on the wiring loom, which had already been done as I explained to them. So with the van now being off the road for 4 months I have replaced the ABS, replace the clusters, ECU has been tested and they say has no faults, I have replaced can gateway under the right hand side of the dash and now I don't know where to go!! Any help/suggestions would be much appreciated

**UPDATE**
Hi all, just an update, I have not been on here for a long time over the ongoing problems with my Caddy.... I have taken it to another garage in november who had it up on the ramp and it was tested for the steering rack modrum, all plugs and wiring underneath and still no joy. It was there for about 6 weeks and again nobody has a clue what it could be! It is now at another garage who was prepared to find the fault and if he didnt find the fault said he wouldnt expect paying, safe to say my money is still in my pocket and I am no nearer a solution. As a last resort this week I bought an ECU kit which included the ECU, the clusters the key with barrel, the gateway and the Body Control Modrum (the one that holds the relays under the dash) all these parts were off exactly the same vehicle only 6 months newer but they were off the 2.0TDI 140bhp we came to plug it in and still no communication with the ECU and the diagnostics. Basically there is no comms on the vehicle even with the ECU kit I bought. Any help at all would be appreciated as this van in going to send me into an early grave!!!
Last edited by Dave c on Thu Feb 27, 2020 10:17 pm, edited 1 time in total.

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Doc
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Re: Caddy Max 2.0 140 No Communication with ECU

Post by Doc » Tue Oct 08, 2019 12:27 pm

Without a proper investigation it's going to be difficult to say but it does sound like you have a wiring issue. Possibly a fuse or relay.
The problem with diagnosing a problem that comes and goes is very difficult as it may not be present when someone is working on it.
For me, a VCDS diagnostic scan would be first port of call, the fault codes usually have mileage, time, RMP logged and this can help determine which module cut off first.

Welcome to the forum by the way.
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I have genuine VCDS Hex V2 & VagCAN Pro for any of your programming needs.

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Re: Caddy Max 2.0 140 No Communication with ECU

Post by robblowen » Tue Oct 08, 2019 1:21 pm

@Dave c hi mate, not sure what you've tried so far and I'm not dead familiar with VAG systems but I have had a wide range of problems before similar to your list, theres a couple of possibilities I can think of.

1 - loose battery terminals, (not insulting anyones intelligence, it's the simple things that catch people out) the unconstant voltage can really mess with can bus systems and throw up some random problems/errors.

2 - knackered battery, I know you said you'd checked the voltage but have you done a drop test? This can throw up the same stuff as loose terminals.

3 - Voltage regulator, similar to the first 2 but I've known this to stop clocks working but still allow the vehicle to start on other vehicles.

4 - DPF, I don't know about VAG but I had a small DPF pipe from the pressure sensor on my wifes Qashqai, it threw up loads of system faults like egr, glow plugs, cruise control, radar, auto stop/start. The systems are all linked on the nissan system so the ECU can create the optimum driving conditions using all the parameters.

Hope you track down the problem dude and get it sorted.

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Dave c
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Re: Caddy Max 2.0 140 No Communication with ECU

Post by Dave c » Tue Oct 08, 2019 2:09 pm

Thanks for the replies, everything that you have mentioned has been checked sadly without any joy! Its had 4 Snap-on diagnostic checks, 1 VAG check and its been to the main dealers without getting into the ECU. The cause is the Red steering wheel light, if I can get this off I can get into it. ?

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Doc
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Re: Caddy Max 2.0 140 No Communication with ECU

Post by Doc » Tue Oct 08, 2019 3:29 pm

The red steering wheel light is either the steering rack or the angle sensor in the steering column. This might be a faulty sensor, power loss or communication loss.
Usually, if the sensor were to go faulty then it wouldn't repair itself. Power and communication faults tend to be more likely to come and go.
Seems you've really fallen foul of some misdiagnosis which has lead to a replace until repaired approach, this can be very costly.
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dan@biali
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Re: Caddy Max 2.0 140 No Communication with ECU

Post by dan@biali » Tue Oct 08, 2019 3:31 pm

As everyone has already said, you will probably need to get someone to really investigate this as we're all just guessing, but these are a few bits I found on the internet with similar faults appearing on the dash and I don't believe you've got all of these but maybe it helps point to the failure (like Doc is saying the wiring or Rob's idea its a power issue).

The red steering wheel light could mean power steering failure (thats what I think it will say in the manual. Are they electro mechanical in all Caddys or are some hyrdaulic? That could be the steering torque sensor on the rack and from what I'm reading, that can't be replaced independently of the rack. Is it a solid red light or is it flashing? If its flashing then that denotes steering column lock malfunction.

The original ! warning light could mean ABS malfunction or the vehicle is low on brake fluid but coming on with ESP light as well could be a sensor fault, a wiring issue or even the magnetic strip in the wheel bearing which is faulty/damaged. Cruise control uses the ABS sensors so thats why it stopped working.

The Button for Driver Assistant System Defective and Error Brake could be communication issue between the cluster and the ecu but it could also be due to low battery voltage - have you put a new battery in or just charged your one? - or could also be a loose or broken alternator control wire. Someone on another forum in a Golf I think had issues, they thought it was the cluster, it was sent for diagnostics and came back fine but still had lights on, they then "traced the loom from the instrument cluster back to the Ecu. What I was told was one of the wires had a resistance that was out of spec so possibly a short, they ran a new wire from cluster to ecu to replace the fault wire" and that solved it. Someone else had the same error message and the techs thought it was a defective steering column electronics control module.

Where are you based? We might be able to give you names of service companies that we trust in these situations to do a thorough investigation.

I found this on youtube where the cluster had loads of fault lights on it and it turned out to be a wheel speed sensor. In other words, it could be literally anything causing it and the dash lights could lead you down a different path!

[youtube]https://www.youtube.com/watch?v=Jg1kFR8FwqY[/youtube]
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Dave c
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Re: Caddy Max 2.0 140 No Communication with ECU

Post by Dave c » Tue Oct 08, 2019 9:49 pm

Hi, many thanks for your help and suggestions, I am based in Whitchurch in Shropshire and yes I am up to £700 now. The only thing we have not tried is what was suggested from you tube, I have seen that video recently myself but at the moment I am struggling to get it on a ramp, the only difference between mine and the you tube video is mine has the red steering light on not yellow, when mine used to be yellow, not permanent red as it is now the van would run perfect, steer perfect and all steering sensors off diagnostics were all set correctly. I have driven the van with the red steering light on with no issued with the power steering whatsoever but its when you turn off the engine and go to restart with the red light on there is no chance and this is also when all communication is lost. I do have my issue on you tube as well, please see attached you tube link....
https://youtu.be/j8i4_STjewI
Thanks Dave

Dave c
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Re: Caddy Max 2.0 140 No Communication with ECU

Post by Dave c » Thu Oct 10, 2019 8:11 pm

Hi never mentioned unplug both plugs off ECU,And the clocks still work with all faults and lights still there is this normal? I was expecting nothing to work with the ECU unplugged😫

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Doc
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Re: Caddy Max 2.0 140 No Communication with ECU

Post by Doc » Thu Oct 10, 2019 8:28 pm

Yes, the ECU relies on the instrument cluster more than the instrument clusters reliance on the ECU.
One plug, the smaller one, on the ECU doesn't go back to the car at all so unplugging that won't do anything for you.
Have you had and checks done on the steering rack wiring? Maybe next time all communication is lost you can try unplugging that to eliminate it from the equation. The plug for it is a 6 position plug located just behind the left side headlight.
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Re: Caddy Max 2.0 140 No Communication with ECU

Post by stan-the-man » Thu Oct 10, 2019 11:36 pm

Is there anything else that the diagnostics have problems connecting to in the van?


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Dave c
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Re: Caddy Max 2.0 140 No Communication with ECU

Post by Dave c » Sat Oct 12, 2019 12:24 pm

HI i have un done the 6 pin plug made no difference traced the wires but nothing ,The Diagnostics snap on will not connect to anything on the van
it is going in next week to a garage i know and they have allso book me a auto electrician so fingers cross we can get to the problem. thanks for your thoughts very much appreciated.

Dave c
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Re: Caddy Max 2.0 140 No Communication with ECU

Post by Dave c » Sat Oct 12, 2019 12:26 pm

stan-the-man wrote:
Thu Oct 10, 2019 11:36 pm
Is there anything else that the diagnostics have problems connecting to in the van?
Hi it will not communicate will anything on the van with the red steering wheel light on
thanks Dave
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Re: Caddy Max 2.0 140 No Communication with ECU

Post by Doc » Sat Oct 12, 2019 1:13 pm

If the diagnostics cannot communicate with anything then it must be your CAN gateway at fault. It is the only thing common to all 3 networks (drivetrain, Convenience, Infotainment) on your van.
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I have genuine VCDS Hex V2 & VagCAN Pro for any of your programming needs.

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Re: Caddy Max 2.0 140 No Communication with ECU

Post by stan-the-man » Sat Oct 12, 2019 1:18 pm

No Comms with units is most likely related to canbus. Was there anything fitted to the van prior to the issues showing.

Any extra wiring added, oem mods fitted etc.

So you did have successful diagnostics session when you managed to clear the faults for Abs etc and now not at all?





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Dave c
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Re: Caddy Max 2.0 140 No Communication with ECU

Post by Dave c » Thu Feb 27, 2020 10:17 pm

Hi I've change the canbus bought one with the same part numbers made no difference
The van as had nothing new to make it come a issue was running fine till crazy yellow lights started and then the dreaded red steering wheel light that was game over then thanks Dave

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