Fault: Parking Brake etc.
Could low battery voltage cause this message about a fault with the EPB and actually prevent the car from starting even though it turns over and over? However, the electronic brake works perfectly by pressing the button which does light up when switched on and both rear motors activate. There are two possibly significant fault codes (unless they are simply caused by a faulty battery even though it shows over 12.45 volts from standing overnight) they are 01314 and 03182. This second code seems to indicate a fault with the clutch position sensor but these codes only appear intermittently and then the fault message disappears and the car starts okay - and yes, my foot is indeed pressed on the clutch as required to start.
Also, if I do replace the battery will it need coding to the car? The current battery is only two years old but was not coded.
B6 Passat 2010 140TDI.
Re: Fault: Parking Brake etc.
The EPB problem won't prevent the car from starting.
Fault code 01314 is - Engine Control Module - No Signal / Communication.
As you can't communicate with the ECU it looks like it is either goosed ( very unlikely ) or it is missing power.
As a preliminary, check all the engine bay fuses & cable connections on the front of the fuse box.
Charge the battery & check it doesn't drop below 12v as you try to start it.
If still a problem you will need a wiring diagram to check what power is missing at the ECU pins or an Auto Electrician who can do the same.
Re: Fault: Parking Brake etc.
Thanks for that - much appreciated. Having never had a problem before with this Passat this is somewhat perplexing and is still intermittent. If the fault EPB message appears it does not start despite turning over and over hence why I wondered about the code 03182 regarding the clutch sensor - as you know you have to press the clutch to be able to start the car but it could simply be insufficient power getting through.
However, I have looked at the ECU (without disconnecting it) and the connections are fine, it is dry and no dampness at all. The fuses appear okay, including the main ones - I even replaced the 460 relay (behind the lower dashboard panel) as a suggestion but it made no difference.
As regards the battery, I replaced it two years ago with a 64ah/640CCA Exide. First thing in the morning it shows 12.45 to 12.50 volts, ignition on it drops to 12.25v, starting the engine it briefly drops to 10.45 then immediately rises to over 14 volts so the alternator must be working okay - I'm told this is normal when starting although it is possible the battery is faulty. I did put it on 'recondition' mode overnight and for two or three days I had no messages or issues with starting. I've noticed that if I load the battery so that it drops to around 12.2v with everything then switched off it slowly rises to around 12.5 volts.
Being intermittent is frustrating - today I've just checked and it is okay but yesterday the message popped up once, switched off then back on again and the message disappeared and all was okay! Should the battery be over 12.6 volts from standing overnight? Maybe this is indeed the problem?
Re: Fault: Parking Brake etc.
Batteries when new sit at about 12.8v, then gradually drop over the years.
My battery which is at least 4 years old sits at 12.2v, but still reliably starts the car first turn of the key.
I do realise that it may not last this winter though.
It doesn't sound like your battery is the problem.
I'm guessing your intermittent loss of power to the ECU is a power connection probably shared by the EPB & so brings that fault code as well when faulty.
But it will be the ECU that is preventing the engine from starting.
It's probably not going to be easy finding this fault as it's intermittent.
But a wiring diagram would be my first requirement, then checking the power wires to the ECU ( 3 I think ) when it next fails.
Re: Fault: Parking Brake etc.
I would clean the various ground points in the engine bay, especially those attached to body work in case there is a bad contact and also the battery terminals and connectors just as a precaution if nothing else. I have a tool that cost a fiver that does the battery ones, then a spray to protect them.
Re: Fault: Parking Brake etc.
Yep, there's no corrosion on the battery terminals, clean and protected. I just don't understand why the EPB throws up a fault when it seems to be working perfectly, or maybe the clutch sensor switch is not functioning correctly, or maybe the battery has a fault that causes it to put out misleading warnings due to an intermittent loss of power or communication - I just don't know.
Re: Fault: Parking Brake etc.
Quote:
Originally Posted by
MDA123
Yep, there's no corrosion on the battery terminals, clean and protected. I just don't understand why the EPB throws up a fault when it seems to be working perfectly, or maybe the clutch sensor switch is not functioning correctly, or maybe the battery has a fault that causes it to put out misleading warnings due to an intermittent loss of power or communication - I just don't know.
Perhaps there is an issue with the clutch sensor or wiring that is causing the ECU to be told the clutch isn't down? The EPB may also be linked into other circuits for example if you have the autohold function which would be where a common link can be found. A short or bad ground somewhere in the starting circuit / clutch position sensor may trigger the EPB fault in these circumstances perhaps?
Look up SSP346 Self Study document on the EPB. It will provide diagrams of the linked circuits and how it all operates with other functions.
Re: Fault: Parking Brake etc.
Thank you - certainly a lot of information in that SSP346 document, including the clutch position sensor, although as regards the EPB and button this works perfectly. Press the button it lights up and both rear motors activate, press it again and they release - no warning lights on the dash. It's just that on another day I press the ignition and up pops that Fault: Electronic Parking Brake See Owners Manual and no matter how many times the starter is engaged the engine will not start despite the battery showing no signs of being weakened. Pull out the key and try again and then, but not always, the message has gone and away she starts! Sometimes I have to re-insert the key several times before the message disappears so leaving me wondering that one day I'll be stuck.
Re: Fault: Parking Brake etc.
You have an intermittent fault which suggests a contact or wiring issue but it could also be bad communication with the ECU. Naturally everything will work perfectly as it often does with bad or almost broken wires, chafing etc or with a less than effective electrical connection that is mostly there but occasionally not including that of an internally failing sensor.
With the 03182 code what was the additional message as this will give an indication of what might be wrong e.g. short to ground, short to plus etc. With older cars I have found good fuses and relays to lose contact even though testing fine across their test contact points on the top, it is the connection between the blades that is important and I have often had to remove many fuses and reseat them to improve or restore an effective connection. Some fuses can also have hairline cracks and work intermittently as a result.
You will need to approach this in a "Diagnose Dan" way and work through the problem testing circuits for power, ground, communication etc. as you go or hand the job over to an auto electrician as suggested in an earlier reply. Intermittent faults are some of the hardest to identify and resolve
Re: Fault: Parking Brake etc.
There were several 01314 ECM codes indicating No Signal/Communication - Intermittent with 03 ABS Brakes, 09 Cent. Elect., 19 CAN Gateway, 44 Steering Assist, and 53 Parking Brake with an additional 03182 Clutch Position Sensor fault under Parking Brake:-
03182 - Clutch Position Sensor (G476)
010 - Open or Short to Plus - Intermittent
Freeze Frame:
Fault Status: 00101010
Fault Priority: 3
Fault Frequency: 4
Reset counter: 209
Time Indication: 0
Freeze Frame:
Voltage: 12.20 V
Count: 57
Speed: 0.0 km/h
Hex Value: 0x1270
Hex Value: 0x0001
Hex Value: 0x0101
01314 - Engine Control Module
004 - No Signal/Communication - Intermittent
Freeze Frame:
Fault Status: 00100100
Fault Priority: 3
Fault Frequency: 11
Reset counter: 209
Mileage: 154831 km
Time Indication: 0
Date: 2016.01.15
Time: 18:49:05
Freeze Frame:
Voltage: 12.60 V
Count: 73
Speed: 0.0 km/h
Hex Value: 0x1270
Hex Value: 0x0001
Hex Value: 0x0101