Glow Plug control unit issues

[BigDaveW]

Hi all

 

My 2018 Superb L&K is throwing up a P064C intermittent error code which comes back after a few days. The control unit is stamped 527. I got hold of a second hand unit from a breakers which is stamped 457 and plugged it in. This one throws up P0673 (glow plug 3 circuit error)

 

So I have two questions

1. What is the actual difference between 527 and 457 Control units? (They are the same size and various searches seem to show them as both fitting my car)

2. Why would they show different codes?

 

Any help would be appreciated please - will maybe swap the glow plugs round at the weekend to see if the fault follows the plug in cylinder 3 when I move it

[Kevinmaj]

Hi mate,

 

I recently got a P0673 error on my 2018 Skoda Superb using my cheap OBD reader so wanted to let you know that Glow Plug 3 is the expensive one of the 4 with a pressure sensor i believe, so not sure you can just swap it out like you state (i'm not a mechanic).  I took my car into Skoda as advised under my Extended Warranty and they confirmed the code error using their readers and replaced the spark plug under warranty.  I'm very happy I took an extended warranty one out on the car now directly with Skoda.

[varooom]

What is the VAG part number on your original item?

The first picture I see 04L 907 xxx y but it's very blurry.

 

Not sure that you can just plop in different number item, not got time to research the difference atm.

[BigDaveW]

The 527 part is 04L.907.282.B

 

The 457 part is 038.907.281.B

[Shugmo]

I've had starting issues, on and off, for a couple of months but it has been ok for the last two weeks.

 

Today the flashing glow plug symbol on the dashboard.

 

Spoke to the garage and they said its more than likely to be the Control Unit, but cannot tell without diagnostics.

 

Is this located in the engine bay?

 

How do you tell from the fuse box layout, is it marked as it's not obvious to me.

 

Thanks

[BigDaveW]

1 hour ago, Shugmo said:

I've had starting issues, on and off, for a couple of months but it has been ok for the last two weeks.

 

Today the flashing glow plug symbol on the dashboard.

 

Spoke to the garage and they said its more than likely to be the Control Unit, but cannot tell without diagnostics.

 

Is this located in the engine bay?

 

How do you tell from the fuse box layout, is it marked as it's not obvious to me.

 

Thanks

In the pick I posted its the one saying 457

[varooom]

3 hours ago, BigDaveW said:

The 527 part is 04L.907.282.B

 

The 457 part is 038.907.281.B

Was busy, so seems you put a very old part on the car, dropped way back in 2013.

Better to get the newer 04L 907 282 B part number item.

 

[ApertureS]

Do not fit a 457! Just cause it looks the same and plugs in doesn’t mean it’s the right one… glowplugs work at varying voltages and in different ways depending on car.

As well as that they may be wired differently and the internal controller will output different signals and receive different signals.

 

This gen of tdi should have a a 527, id first be checking a specific manufacturer fault code to get more details and then check wiring for faults before replacing components 

[J.R.]

I doubt that it's anything more than a relay or relay timer inside, looks to small to contain the PWM circuitry, I would have to see a wiring diagram to be sure but its unlikely.

 

To my knowledge they are all relays but have different numbering and usually different pin polarisations to prevent the wrong type being fitted or put in the wrong location.

 

Often the coild and contact(s) pictogram is on the side so you could compare, otherwise I would trace my way through it with a multimeter to find the coil contacts, the common, NO and Nc contacts and compare the two.

 

I have often fitted a standard relay when a specially numbered and polarised VAG one has failed using male jumper wires with male and female connectors.

 

They only make them different and call them different names to make you buy the relay from them, some are indeed special relays, I am thinking of the one for the fuel injection pump on an old XR3i Ford that would only energise when it detected high voltage transients from the spark plugs, a safety measure.

[Gammyleg]

Ridiculous price for a relay!!

 

Many years ago one of the ABS relays on my Citroen failed and I was quoted similar price from main dealer to supply a replacement. "Common fault, can't be dis-assembled and not a serviceable part" they said..... Mmmm, really?

Took it apart, removed the rotted-out pin and replaced with a blade from an old fuse. Cost was ...er £0.00.

 

More in line with the topic, all the glow plugs on my 1.6tdi were replaced @ 50k miles. This was before my ownership so can't offer a reason as to why but presumably not too an uncommon event. 

[BigDaveW]

I put the old 527 relay back in and no faults for 48 hours. This is the same as before where the fault code would only appears after about 3 or 4 days.

 

Any ideas if how to diagnose something that intermittent?

 

Or why the 457 relay throws the glow plug fault immediately and the 527 doesn't? 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Shugmo]

So it appears that all my glow plug warnings, occasional sluggish start, were down to the battery only having 49% capacity.

 

Diagnostic test, new Yuasa battery and coding, £204.

 

Wasn't expecting a battery, so happy that the glow plugs all seem ok.

 

Here's to the next 100,000 miles.