Power Cord/Glow Plug Flashing: Troubleshooting

I installed an intermediate connector for multi-wire connection on my Bora 110 PS TDI. Everything worked perfectly in the winter. Now (as it's getting warmer), the preheating lamp sometimes lights up shortly after starting. What could be the problem? The workshop can't find any errors without a chip.

Hi.

Regarding the term choice in the heading: Chiptuning is actually "used" to describe modifications to the software or maps in the engine control unit.
To avoid misunderstandings, I have renamed your post accordingly.

Regarding the issue: When starting up, an automatic pump dispenser check is performed, which detects any tampering.
Therefore, any interference should be introduced to the sensor signal only after this check, i.e., no earlier than approximately 20 seconds after the engine is started, which is what most power boxes and plugs do.

In your case, this delay might be too short, or it might not be implemented at all (in which case, it would be a design flaw).
Or, the tuning is set too aggressively, which can lead to the detection of implausible inconsistencies between the control signal and the feedback from the pump, even during normal operation --> adjust the connector to a slightly weaker setting.

The workshop should receive a message regarding the pump when querying the error memory.
If she has absolutely no idea what's going on, it suggests that she's not utilizing the error memory functions – a weak signal (unless the error has been cleared because more than 50 engine starts have occurred since the last time the plug was used).

You might be right about that. But why was there nothing at 20,000 km, and now (of course, only when it's a little warm) it happens occasionally? Could it also be due to the standard air filter?

Hello,

As Ulf already mentioned:
If the preheating indicator is flashing, there is definitely an error code stored in the system. If your workshop is unable to read this error code, you should consider finding a different workshop.
To further narrow down the error, you could post the result here.

Markus0 wrote:

But why was there nothing at 20,000 km in the winter, and now (of course, only when it's a little warm) it happens occasionally? Could it also be due to the standard air filter?

Hi.

The measured values for the plausibility check (setpoint generator, current of the flow controller) change slightly with temperature.

An error is detected when the tolerance band for "OK" is exceeded.
If the power plug (I assume it's plugged into the pump's cable) distorts the readings to the very edge of the error threshold, it's possible that normal temperature-related fluctuations could be the deciding factor in whether or not a fault is detected.

I don't think the air filter has anything to do with the problem.

I've also already turned the potentiometer down, but it still happens. If I unplug the cable and wait for about 10 hours, the message no longer appears (without the power cable plugged in).

Markus0 wrote:

I've also already turned the potentiometer down, and even then it still happens. If I unplug the cable and wait for about 10 hours, the message no longer appears (without the power cable plugged in).

Then it seems the connector may be interfering with several "sensitive" areas, of which only one function can be adjusted via a potentiometer.

My experience is that if the pump is in its "original" state when the engine is first started, the warning light remains off, even if the engine was running just one minute before with a faulty pump setting (and the warning light).
The (currently non-existent) pump error will remain active for another 49 engine starts or until it is cleared from the error memory. Nevertheless, the engine is running in the normal program.