Embedded Chiller Heating: Troubleshooting Guide

Hello,

I installed a coolant heater in my Golf 3 AHU.
Pins 6 and 26 of the MSG activate the relays.
I installed two relays and followed the original schematic exactly.
But it's not working.
I've already been to a VW service center, and they performed an actuator test.
'Then both relays are working!'
Could it be that something needs to be programmed?
And at what temperature does it turn on?
And I believe the temperature reading is coming from the air mass meter temperature sensor!

Best regards, Marco (Netherlands)

Hi Marco.
Dein Deutsch ist spassig; mein Niederländisch wäre wahrscheinlich noch witziger. AOkay, let's get back to the serious stuff.

The temperature signal likely does not originate from the mass airflow sensor (MAF), as that would cause the glow plugs to be constantly heated in the winter. The signal (or resistance) should instead come from the coolant temperature sensor located on the cylinder head.
Unfortunately, I can't tell you the exact temperature at which it typically switches. My suggestion is between less than +5°C (as an activation temperature) and +30°C (as a deactivation temperature).

Regards,
Hermann.

Hi Marco.
Dein Deutsch ist spassig; mein Niederländisch wäre wahrscheinlich noch witziger. AOkay, let's get back to the serious stuff.

The temperature signal likely does not originate from the mass airflow sensor (MAF), as that would cause the glow plugs to be constantly heated in the winter. The signal (or resistance) should instead come from the coolant temperature sensor located on the cylinder head.
Unfortunately, I can't tell you the exact temperature at which this typically switches. My suggestion is between less than +5°C (as an activation temperature) and +30°C (as a deactivation temperature).

Regards,
Hermann

I don't believe that the system must function in a standard way!
I connected everything as it should be!
Can't we program something to do that?

Best regards, Marco.

Sure, here is the translation of the text from German to English:

'P.S. Sorry for the bad German!'

Hi,

I just made a discovery!

Check out the encoding schemes for the control units in this thread.

https://community.dieselschrauber.org/en/viewtopic.php?t=4019

Such a coding scheme is based on binary, meaning:

Feature 1 * 1 + Feature 2 * 2 + Feature 3 * 4 + Feature 5 * 8 + ... + Feature n * 2^(n-1)

Feature x takes a value of either 0 or 1.

In the thread above, all the encodings are currently set to "straight" (i.e., Feature 1 = 0), with the exception of those from Voss, Gremlin, and myself.

Voss and Gremlin have automatic transmissions, while I have a manual transmission. However, what all our cars have in common is that they DO NOT have glow plug heaters!

My theory is: Odd encoding means GSH is off.

Can anyone confirm or refute this?

@Marco: Wie ist deine Codierung? Even odd numbers?

The actuator diagnosis also works for me; it doesn't report any errors, even though no relays are connected. This aligns with Marcos' statement that the actuator diagnosis causes the relays to click, meaning the outputs are activated in diagnostic mode.

What do you think?

ADDENDUM: According to https://community.dieselschrauber.org/en/viewtopic.php?t=2260&highlight=codierung, the specific area responsible for encoding switching/automatic functions, which would contradict this theory. However, this then raises questions about the programming of my MSG.

Here are more people importing from the Netherlands... what encoding are you using?

Best regards,

Jan.

Hello,

I'd rather stay out of Jan's code speculations; I'm not very tech-savvy.

@marco:
You can, as far as I know, simulate the activation conditions for the glow plug heater as follows.

Connect a fixed resistor of approximately 8 to 10 kOhms to the connector of the intake air temperature sensor (charge air temperature). This will tell the engine computer that the outside temperature is very cold, which is a criterion for activating the glow plug system (GSH).

The engine should be cool (not warmer than approximately 0°C).

Then simply start the engine, let it idle, avoid turning on any electrical devices (like lights), and wait for about 1 minute - at the very least, the relay for the low heating power should be activated by then.
The relay for high power comes approximately 20 seconds later. Initially, the relay for low power is switched off again, and then switched on again approximately 20 seconds later - provided that the alternator load still has available capacity.

That's roughly how things are going for me with my AFN.


Regarding the LiMa (alternator): Is the LiMa DF (direct frame) connection to the engine control unit okay (no error messages)?

There are essentially only two relevant coding schemes.

00001 = automatic
00002 = manual transmission

When the system is set to 'automatic,' the actuator test for the glow plug heating system is not displayed.

If the actuator test works (which, according to Marcos' workshop, it should), then the only possible sources of error are those suggested by Ulf.

- faulty temperature sensor.
- Starting temperature too high (unnecessarily heating up).
- DFM (field management) connection to the alternator is missing, not connected, has a broken wire, etc.
- Alternator overload (weak battery / too many consumers).

The operating status of the heating system can be checked in measurement block 16 of the engine control unit, and the lighting system load can also be read from there.

16.0, Additional Heater
16.1, Generator loading,
16.2, Auxiliary heat, (see label file)
xxxxxxxxx
; bit meaning from left to right.
; 1 Not relevant
; 1 Not relevant.
; 1 Coolant temperature sensor G62 or intake air temperature sensor G72 is faulty.
Engine start in the last 10 seconds.
Engine operating below 870 rpm.
; 1 Battery below 9 volts
; 1 Generator faulty
; 1. Coolant temperature > 70-80C or Intake Air Temperature > 5C
16.3, Activation, Hi/Lo
; xx
;bit meaning from left to right
; 1 High heat output, J360 on.
1. Low heat output, J359 model.
16.4, Voltage supply, from ECM.

CU Gremlin.

Hi Gremlin,

Quote:

There are essentially only two relevant coding schemes. 00001 = automatic 00002 = manual transmission When the system is set to "automatic," the actuator test for the glow plug heating system is not displayed.

Hmm... but what about 00005 then?

It seems like it's not a simple binary system, because if it were, the bit for the automatic function would be activated at 00005, which, according to your text, would prevent the actuator test from being displayed. However, I *am* seeing the actuator test displayed at 00005...

That's why the idea is that this still plays a role in the use of the GSH. The actuator test only indicates that the MSG *can* control the relays (if present), but not that it *actually does* control them.

Then, in the thread you mentioned, Bertil also had an engine control unit with the code 00012, but that was a PD unit.

Best regards,

Jan.

Hi Gremlin,


Hmm... but what about 00005 then?


My list only goes up to 00004; that would be an automatic without ABS.

It doesn't necessarily have to be binary or bit-encoded. While experimenting, I noticed that some control units (like the EDC, for example) don't always react to individual bits, but seem to interpret the entire value as an integer.


That's why the idea is that this still plays a role in the use of the GSH. The actuator test only indicates that the MSG *can* control the relays (if present), but not that it *actually does* so.


That's why I highlighted a line in the measurement block list .

CU Gremlin.

Hi Gremlin,

Quote:

That's why I highlighted a row in the measurement data block list.

I also noticed and understood that. However, that's not what I meant; I meant:

What happens with an MSG (Micro Servo Generator) that doesn't have a connected GSU (Gear Servo Unit) from the factory, but is also programmed with SG (Servo Generator) functionality, when these conditions are met? Does it supply power to the inputs, or does it not, because it is aware of this circumstance (e.g., through programming)?

When it gets warmer, and if I find the time, I can try it out.

Best regards,

Jan.

What happens with an MSG (Micro Servo Generator) that doesn't have a connected HGS (High-Gain Servo) from the factory, but is also programmed with an SG (Servo Generator) code, when these conditions are met? Does it supply power to the inputs, or does it not, because it is aware of this circumstance (e.g., through coding)?


I would say that the relevant inputs should be connected to ground, just like with the heating relay. If there isn't a relay connected, the EDC won't switch anything to ground.

So, the best approach would be to connect an LED with the appropriate resistor to the 12V supply and the EDC input, and then see what happens.

Cu Gremlin.

Hi,

Quote:

So, the best approach would be to connect an LED with the appropriate resistor to the 12V supply and the EDC input, and then see what happens.

I'll go ahead and test that now... I just didn't know that they were switched to ground, I was expecting 12V outputs.

However, I'm not entirely sure about Marcos' observations regarding this behavior, which is why I'm asking this seemingly trivial question. If the relevant piece of code is disabled through encoding, then nothing should happen.

"To put it another way: Has anyone ever installed a heated steering wheel in a car with a manual transmission that didn't originally have one, and did it simply work afterwards?"

Best regards,

Jan.

Gremlin wrote:

I would say that the relevant inputs should be connected to ground, just like with the heating relays. If there isn't a relay connected, the EDC won't switch anything to ground...

Hi Ralf,

At the very least, the relays that are relevant for exhaust emissions are not only activated by the EDC (Electronic Diesel Control), but also electrically monitored.
For example, if the connector for the AGR valve magnet has come loose, an error code will be logged.

I don't know for sure if the GSH relay is also being monitored. But if it is, then there should be a constant error message displayed on Jan's Ibi system.
Unless the engine computer is programmed to ignore it.

Hi,

Quote:

I don't know for sure if the GSH relay is also being monitored. But if it is, then there should be a constant error message displayed on Jan's Ibi system.

After the actuator test, I immediately read the error memory, but there were no error messages. Also, during the test itself, there was no feedback that would indicate a missing hardware component. Only the clicking sound and the dimming of the lights did not occur.

It is, of course, possible that such monitoring is deactivated during actuator testing.

Quote:

Unless the engine computer is programmed to ignore it.

Either that, or my previous assumption that the relevant routine in the MSG is being bypassed or circumvented through encoding.

As I mentioned... since my coding is different from Ulf's Ibi GP01 (or his wife's), there might be something going on in that area.

Best regards,

Jan.

Hello,

Thank you all for the information and help!
I'll try to figure that out!

Best regards, Marco.