VW Passat - Engine management & battery light on!

mama79

Hi

Hoping someone can help me. About 2 months ago the engine management light & battery light came in on in my 2004 VW Passat (1.6 petrol )I thought it was the alternator so I took it to my mechanic who did full diagnostics and replaced the battery. He said there didn't seem to be any issue with the alternator.

Yesterday evening the same lights have come on again. I'm going to take it back to him today if I can get out of work but just wondering if this is just a sensor that needs resetting or do any of you think its something more serious?

Any advice appreciated..

cheers

studdlymurphy

Is there any problem starting sluggish like the battery is anyway low?
Did the car get wet at any stage?
Diagnostics would be the best start I think

mama79

Hi & thanks for getting back to me.

Car is going fine. No hassles with starting it or anything. Just spoke to mechanic and he reckons the alternator may need rewinding? Not really sure what that means or more importantly what its going to cost me

studdlymurphy

70-80 euro should cover you

mama79

Hiya thanks for the heads up on price hopefully that's all it needs !

mama79

Hi

Bumping up this thread hoping someone can help out...the engine management & battery lights have come on again :mad:.

Following on from my previous post, the mechanic looked it over and replaced the alternator regulator and turned off the engine & battery lights. He said he was onto VW Ireland and they said it may be something to do with a wire that may have a broken connection and if it happened again to bring it back and they'll have to trace the faulty wire. He said the alternator and battery were fine.

The thing is the last two trips back to him have cost about €100 each and that's not something I can keep paying out every couple of weeks.

Am I better off with an auto electrician at this point?

Once again, all advice welcome..

thanks

jimgoose

mama79 wrote: »

Hi

Bumping up this thread hoping someone can help out...the engine management & battery lights have come on again :mad:.

Following on from my previous post, the mechanic looked it over and replaced the alternator regulator and turned off the engine & battery lights. He said he was onto VW Ireland and they said it may be something to do with a wire that may have a broken connection and if it happened again to bring it back and they'll have to trace the faulty wire. He said the alternator and battery were fine.

The thing is the last two trips back to him have cost about €100 each and that's not something I can keep paying out every couple of weeks.

Am I better off with an auto electrician at this point?

Once again, all advice welcome..

thanks

You need to get hold of any DTC codes stored by the cars computer, and post them up here. From there, the next step would be to locate someone who understands fault-finding and debug, and not just guesswork and parts-swappery.

tossy

mama79 wrote: »

Following on from my previous post, the mechanic looked it over and replaced the alternator regulator and turned off the engine & battery lights. He said he was onto VW Ireland and they said it may be something to do with a wire that may have a broken connection and if it happened again to bring it back and they'll have to trace the faulty wire. He said the alternator and battery were fine.

So the first time he said the alternator was fine and replaced the Battery,and the second time he replaced parts but said if the fault returns then it's down to a faulty wire....... Surely then he is only replacing parts and hoping for the best.


You need to get your car scanned with a diagnostic computer like VCDS and find out exactly what the ECU is telling you. Armed with that any competent mechanic should steer you right.

A 100e to change a battery is pricey at best.

Where are you based?

mama79

tossy wrote: »

So the first time he said the alternator was fine and replaced the Battery,and the second time he replaced parts but said if the fault returns then it's down to a faulty wire....... Surely then he is only replacing parts and hoping for the best.


You need to get your car scanned with a diagnostic computer like VCDS and find out exactly what the ECU is telling you. Armed with that any competent mechanic should steer you right.

A 100e to change a battery is pricey at best.

Where are you based?

Hi Everyone thanks for the replies...i'm in Cork. Working near enough to Cork City but live near Kinsale direction...
How do I get a hold of DTC codes..sorry if I'm a bit thick

tossy

mama79 wrote: »

Hi Everyone thanks for the replies...i'm in Cork. Working near enough to Cork City but live near Kinsale direction...
How do I get a hold of DTC codes..sorry if I'm a bit thick

If you were in Kildare i could have scanned it for you,maybe someone near Cork can offer or at least recommend a competent Mechanic.

jimgoose

mama79 wrote: »

Hi Everyone thanks for the replies...i'm in Cork. Working near enough to Cork City but live near Kinsale direction...
How do I get a hold of DTC codes..sorry if I'm a bit thick

DTCs are diagnostic trouble codes - the legendary "Fault Codes" logged by the on-board diagnostics (OBD-II) on modern cars. A competent mechanic can read them for you, or it can be done with a cheap-and-cheerful OBD-II scanner like a Memoscan U480.

Sam Russell

I had a problem with my Passat which was caused by the chamber in front of the windscreen filling with water and corroding the wires going to the ECU. The chamber houses the ECU and the battery and servo and all the main wire harness. VW conveniently have two drain holes in there to keep everything nice and dry - one under the servo and the other under the battery! Check for water on the floor behind the driver's seat which is where it ends up.

It is a known fault with the B5 chassis and VW know about it, hence their coded warning about a broken wire.

Take the car to a VW dealer if this is the problem as they will fix it, or sell the car.

tossy

Sam Russell wrote: »

Take the car to a VW dealer if this is the problem as they will fix it, or sell the car.

Great advice :rolleyes:

Sam Russell

tossy wrote: »

Great advice :rolleyes:

He has already gone to a mechanic and had a new battery and a new alternator. What else does the mechanic need to change before he finds the fault? At least the VW dealer has the kit to diagnose the fault and ask VW for backup if the fault is elusive. It might be expensive going that way but it should be fixed. The alternative is to sell the car at auction.

tossy

Sam Russell wrote: »

He has already gone to a mechanic and had a new battery and a new alternator. What else does the mechanic need to change before he finds the fault? At least the VW dealer has the kit to diagnose the fault and ask VW for backup if the fault is elusive. It might be expensive going that way but it should be fixed. The alternative is to sell the car at auction.

even with a lnoger explanation it's still dreadful advise.

Don't bring a 10 year old passat to a VW main dealer to diagnose a problem that might take some time,that's financial ruin waiting to happen. Any decnet mechanic or garage has the kit to diagnose the fault.

Rather than stick with a mechanic who changes parts and hopes for the best,just change mechanic.

Sam Russell

tossy wrote: »

even with a lnoger explanation it's still dreadful advise.

Don't bring a 10 year old passat to a VW main dealer to diagnose a problem that might take some time,that's financial ruin waiting to happen. Any decnet mechanic or garage has the kit to diagnose the fault.

Rather than stick with a mechanic who changes parts and hopes for the best,just change mechanic.

I am basing this on my experience.

How do you select a mechanic who can fix a problem like this? It is expensive to go through 4 or 5 'swappers' at €100 or €200 a pop. There are too many faults that can cause this type of problems and a shortage of mechanics that can fix it. Lambda sensor, MAF sensor, the other lambda sensor, various tempersture sensors, the air filter, the fuel filter, the ECU, a relay, another relay, etc., etc., and then they start again because the parts swapped by the previous guy was not 'genuine VW' and so spurious.

Heart breaking, as well as wealth breaking.

mama79

Hey everyone thanks again for all the replies...its maddening that the car drives great but this light keeps
showing.

Re the dealership tip to be honest the husband had a very bad experience when he took his 2003 Vw Passat to a VW dealership in 2007 for a basic service. To cut a long story short they told him that the car needed about 2.5k worth of work and was totally unroadworthy. They said that the power steering amongst other things was gone but then changed their mind when he said that they'd only serviced the car 6 months prior...think they were trying to sell him a new car....
Sorry for the rambling post if anyone can recommend a decent mechanic/ auto electrician in cork who can get to the bottom of this I'd appreciate it.

jimgoose

mama79 wrote: »

...if anyone can recommend a decent mechanic/ auto electrician in cork who can get to the bottom of this I'd appreciate it.

John Dooley, on the Bandon Road on the right before you come to the viaduct. He does a lot of big Mercs of all ages, as well as other stuff. Kevin there is handy enough with the diags. There's also Ian Ahern of Munster Jag in Spur Hill. Top man, Jag tech with 12 years or so under his belt. Others may recommend more.

mama79

Thanks Jimgoose I might give them a shout today...:)