EPC warning light?

[Dappernut]

Has anyone with a facelift model experienced an EPC warning and the car dropping into limp home mode please?  Wondered if it is relatively common or just me.

[Porto]

On 20/03/2023 at 19:52, Dappernut said:

Has anyone with a facelift model experienced an EPC warning and the car dropping into limp home mode please?  Wondered if it is relatively common or just me.

Error gone next day all by itself.

[Dappernut]

Thanks for the feedback Porto.  In my car the EPC error seems to be intermitently provokable by manually overriding DSG gear whilst using adaptive cruise.  Certianly, that's the only time I've ever seen it.  The dealer says it's not possible for it to be related however and it must have been a coincidence when it's happened.  🤨

[Porto]

I really glad to hear that issue was fixed! 👍

[Ootohere]

@DappernutHow many miles has the car done?

 

Was that the Technician that said not possible to be related to using manual shifts? 

Like maybe getting a misfire!

Did they check for any logged fault codes?

Edited 8 December, 2023 by Rooted

[Dappernut]

13 minutes ago, Rooted said:

Did they check for any logged fault codes

 

They didn't mention, but I'd checked with an ODB11 and there was nothing logged.   ...which seems strange given it had put the EPC light on and gone into limp mode.  And yes, confirmed, allegedly EPC can not be related to manual shifts nor adatptive cruise.   ...even though I had it happen three times.

[Ootohere]

?

How many miles has the car done?

 

When Fabia Mk2 vRS had issues with the Water Pump / Supercharger Clutch it might show when you really accelerated hard and it might go into limp mode.

(Also slight coolant leaks.  But a plug on the way out could also have the EPC or Engine Emissions light on or both.)

 

But often for those that not booting their car hard and having it happen it could be when in Cruise Control that the EPC showed as you were going up a hill and the car dropped a gear and then the light came on or it went onto limp mode.)

 

Or it could just be they were running 95 ron and not super unleaded, and that was years before E10. 

 

I would try some E5 if you do  not already use that.

 

Edited 8 December, 2023 by Rooted

[Dappernut]

Last time it did it, about 12K miles.  Run almost exclusively on Shell VPower E5.  Using adaptive cruise, car would try to labour up a hill at about 40 mph in 7th gear behind another vehicle - hit left paddle to shift down and straight away EPC and limp.  Many miles of separate cruise, agressive booting and manual shifting and nothing.  It's only downshift in cruise when I thought the gear being held was way too high that's ever produced the fault.

[dandandan]

Have you noticed the oil temperature going up and down like in this other topic?

 

 

[Dappernut]

5 hours ago, dandandan said:

oil temperature going up and down

 

Nope, nothing like that for me.  Oil temperature stable.  That is to say, in line with what I'd expect given the ambient temperature, road conditions and how I'm driving. 

[Pugmanone1]

As all these systems run on the can bus system it’s totally possible for the EPC light to come on due to use of the DRG in manual mode. The use of Can Bus saves the car manufacturers a bit of money by reducing the amount of wiring used in a car, but the linking of totality unrelated devices to each other makes fault finding so much harder. 

[Dappernut]

Indeed.  We used to have a Ford C-Max with an intermittent failure to start problem that was eventually traced to a faulty rear hatch lock mechanism causing problems on the C-Bus.

[Pugmanone1]

12 minutes ago, Dappernut said:

Indeed.  We used to have a Ford C-Max with an intermittent failure to start problem that was eventually traced to a faulty rear hatch lock mechanism causing problems on the C-Bus.

Can-bus is a big problem for motorists. In America manufacturers are using it force owners to buy new filters for carbon reduction, miles before a new filter is needed. Air conditioning is switched off, or power steering is reduced. This is costing motorists thousands of dollars extra a year as garages need to fault find endless error codes not related to the real problem. I remember my next door neighbour had a Land Rover discovery which went into limp mode when it wanted. It cost him over £5000 to find out it was the radio at fault. All down to can-bus. 

[Dappernut]

Not fit for purpose, class action lawsuit eventually perhaps?  Pee off a senior lawyer enough, or let the ambulance chasers get a sniff of a big payday.  Careful what you wish for though.

[Breezy_Pete]

CAN is just a communication network, CAN Bus Explained - A Simple Intro [2023] – CSS Electronics

You guys seem to be trying shoot the messenger.

How the data conveyed by the bus is used seems to be the problem you think there is.

 

[Pugmanone1]

30 minutes ago, Breezy_Pete said:

CAN is just a communication network, CAN Bus Explained - A Simple Intro [2023] – CSS Electronics

You guys seem to be trying shoot the messenger.

How the data conveyed by the bus is used seems to be the problem you think there is.

 

Not at all, as stated can-bus throws up all sorts of problems. Andvghr only reason it's there is to cut down in wiring for car manufacturers. And of course the other problem is the very poor quality of the wire being used in the wiring looms and the over use of plastics.

[Breezy_Pete]

The CAN bus just sends the messages. The controllers are what tells you about the message contents. 

It's like you're trying to blame the phone line for someone telling you bad news.

[Pugmanone1]

4 minutes ago, Breezy_Pete said:

The CAN bus just sends the messages. The controllers are what tells you about the message contents. 

It's like you're trying to blame the phone line for someone telling you bad news.

Please explain to me how a radio can course the car to go into limp mode. Surly this is down to a drop in current and relayed by the can-bus.

[Breezy_Pete]

Only if the programmers wrote the software in the radio and engine ECU in such a way that it allows this to happen.

 

[Dappernut]

1 hour ago, Breezy_Pete said:

Only if the programmers wrote the software in the radio and engine ECU in such a way that it allows this to happen.

 

 

To be fair, I don't think the average user would really make a distinction between the bus itself and they the way attached components use that bus.  I'll happily accept however that most major car manufacturers don't make great software developers.

[Breezy_Pete]

Actually I suspect the software guys have done exactly what they've been asked to do.  But I guess that doesn't really contradict what you've just said.

 

Edited 4 January by Breezy_Pete

[Breezy_Pete]

Anyhow, to the problem.

Find a local VCDS user who may be willing to scan the car for you to see why the EPC light is being lit?

A generic OBD reader may have failed to pick up the stored info.

 

 

[J.R.]

4 hours ago, Breezy_Pete said:

The CAN bus just sends the messages. The controllers are what tells you about the message contents. 

It's like you're trying to blame the phone line for someone telling you bad news.

 

Very well put.

 

Don"t shoot the messenger springs to mind.

 

Can bus is frequently misquoted and misrepresented always by those who do not understand what it is, what it does and why it is present.

 

All the idiots selling so called can bus compatible LED bulbs dont help either.

 

One great benefit of the individual controllers that communicate via the canbus network is distributed intelligence, the individual systems can all continue working in a degraded mode (whatever that is in English) when the network is not functioning and/or other controllers have failed or lost power.

Edited 4 January by J.R.

[Dappernut]

On 04/01/2024 at 16:21, Breezy_Pete said:

why the EPC light is being lit

 

Power cycling the car gets rid of the EPC light and nothing seems to be getting stored.  Neither ODB11 nor the dealer could see anything.

[Breezy_Pete]

OK but if you can provoke it by driving behaviour, you can potentially read the code while it's lit?