Polo Glow Plug Error: Get Help Now!

I read the error codes from a colleague's car because the engine warning light came on again.

VW POLO 2005 TDI

Here's the result:

Tuesday, April 1, 2008, 12:35:36:39193
VAG-COM Version: RKS 704.1

Address 01: Engine.
Control unit part number: 038 906 019 NJ.
Component and/or version: 1.9L R4 EDC G000SG 6412.
Encoding: 00002
Workshop number: WSC 31414.
Extended information: WVWZZZ9NZ5D045273 VWZ7Z0D1135460
"One error found:"

17057 - Glow plug, cylinder 3 (Q12): electrical fault in the circuit.
P0673 - 35-10 - - - Intermittent.

Readiness: 1 1 0 0 0

The worst thing is that this problem hasn't appeared for the first time. We've already installed two new glow plugs, two preheating control units, and a new wiring harness. Unfortunately, the authorized workshop is unable to fix the issue.
Does anyone have any idea what this could be? Perhaps the engine control unit itself?

I found another error in the vehicle's electrical system. It might be related to something.
See here:

Address 09: Body Control Module.
Control unit part number: 6Q1 937 049 D.
Component and/or version: 0000 BN-SG. 1S34
Encoding: 09662
Workshop number: WSC 31186.
"One error found:"
01598 - Voltage of traction battery.
07-10 - Signal too weak - Sporadic.

It's a rather odd entry, isn't it?

Thank you very much for your help.

If the battery isn't providing power, I could imagine that an overly sensitive ignition control unit might interpret that as a fault with the spark plug.

Maybe try a new battery before replacing a bunch of light bulbs.

m;

Can you use a multimeter with a data hold function to measure the lowest voltage of the battery when starting the car? Ideally, do this in the morning: turn on the lights as usual and then immediately start the car.

I actually thought the same thing, but I was under the impression that a car repair shop would rule out such a problem first. Fortunately, the colleague extended his warranty.
Unfortunately, the warranty will not cover the battery, as it is considered a wear and tear item.

The car already has a long and complicated history. It's truly a dream object for people who use VAG-COM. A classic "Monday car" (meaning it's likely to have manufacturing defects).
Constantly having problems with various control units.
The ABS control unit is new due to several malfunctions. The engine control unit has also been replaced, and the air conditioning system is constantly causing problems.
I would literally burst out laughing if all those problems were caused by a faulty battery.

Tobi76 wrote:

I would literally burst out laughing if all those problems were caused by a faulty battery.

It's not that far out of the ordinary... Or maybe there's a bad connection at the ground or the battery...

So, the battery doesn't drop in voltage significantly. Therefore, the problem wasn't related to the battery.
I find it strange, however, that the workshop can't find the battery fault in the error memory.
As you can see, it's definitely there. See above. I didn't delete it so that the mechanics could find something.

I have now learned that the cables have not yet been replaced, as they can only be changed along with the entire engine wiring harness.
Personally, I wouldn't care at all; it's under warranty anyway. They can even replace the engine control unit if they want.

Regarding the required vehicle inspection (TÜV), which obviously wouldn't pass with a lamp like that, the company responded: "Then why don't you have the TÜV done with us? It will only cost 20 Euros more."

I would have switched to a different dealer a long time ago.
Can the warranty claims for the Garnatiefälle product be processed by any authorized dealer of your choice?

Hello, has the error been found yet?

Possibly update the MSG with a new data set, unless it has been chipped.

Currently, the software version should be 9810, just in case someone tells you "everything is okay, there's nothing newer."

Best regards, Rainer.

Hello,

If you hear the whole story, it's probably not actually about any spark plugs, but just misleading error messages. It's likely a bug in the electrical system, and the control units can't clearly assign it to a specific fault.

Basic faults that could cause the entire electronics to malfunction include things like the alternator regulator, the battery, and the wiring harness.

A faulty sensor could disrupt the electrical system with unsightly voltage spikes and mislead the control units. A battery with high internal resistance might not perform its filtering function adequately. A wiring harness chewed on by a rodent could potentially cause sleepless nights for the maintenance personnel (and later for the customer, as this is not covered by the warranty). Classic issues also include oxidized ground connections, which can put the entire vehicle electrical system in a state of instability, as well as oxidized cable connectors and couplings. Wasn't there a separation point between the engine compartment and the passenger compartment that was prone to oxidation?

I would start by checking the car for signs of badger activity and applying contact spray to all connection points. Don't forget the battery and alternator connections.

Hello,

Thank you very much for the numerous responses. The error has not yet been found. I have scheduled a meeting with a colleague for next week to review everything.
I once obtained the wiring diagrams, but they don't show a separate glow plug control unit. It seems everything in the Polo is handled by the engine control unit and the vehicle's onboard network. However, there are only two wires connected to the glow plugs, so two plugs are connected to each wire. Now I'm wondering how the control unit can tell which of the plugs is defective. Can anyone explain this?
Der Fehler wandert im Moment zwischen den einzelnen Kerzen. Strange, isn't it?
I'll start by checking the individual connectors. It would also be interesting to look at the main fuses.
How can I detect voltage spikes from the LIMA regulator, or is a changeover only helpful if I suspect a problem?
Since the car is still under warranty, my question is whether our modifications might have negative consequences for the warranty.

Tobi76 wrote:

I once obtained the wiring diagrams, but they don't show anything about a glow plug control unit. It seems that everything in the Polo is controlled by the engine and body control units. However, there are only two wires connected to the glow plugs, so two plugs are connected to one wire. Now I'm wondering how the control unit can tell which of the plugs is defective. Can anyone explain this?

It's very simple: You have the wrong wiring diagram.
If error messages appear for individual glow plugs, (in the Polo) as far as I know, there's always a separate glow plug control unit involved. The MSG 019NJ indicates that you have the BLT version: with an extra glow plug control unit.