Octavia 2.0 TDI: Intermittent Power Loss & Misfires

Hi.

"On my 2008 Octavia 2.0 PD TDI (BMM), I'm experiencing intermittent issues with the car, specifically occasional hesitations or power loss. This usually happens when overtaking, and there's a period of about 1-2 seconds where there's no power at all (I suspect that no fuel is being injected during that time). Of course, there are no error codes stored in the system."
When the problem occurs, the preheating and DPF lights illuminate, and approximately 1-2 seconds later, both lights turn off and everything returns to normal.

Are there any usual suspects? I suspect either a problem with the voltage supply from the engine control unit, or possibly a loose connection in the wiring of the PD injectors.

As I said, there are no errors in the memory, and it doesn't enter a failsafe mode. Of course, this behavior is not reproducible.

I also suspect there might be issues with the power supply. What surprises me is that, without power to the engine control unit, the glow plug lamp shouldn't be lit.
Also, also consider other possibilities as well, and also check for other fuses that might have loose connections, look for chafing on the wiring harness, etc.

Best regards, Rainer.

Hi.

"I checked the fuses, and they are all fine. I also didn't find any loose connections in the fuse box or main electrical panel. I haven't checked the rest of the cables in detail because I didn't want to disassemble everything. Currently, the problem isn't happening anymore, and everything seems normal. However, now the seatbelt buckle is malfunctioning, and the seatbelt warning light keeps coming on during the drive."

Thank you for the feedback! Were you able to confirm that the seatbelt warning is actually related to the lock and not a general fault (e.g., a worn spot/damage) in the wiring harness?

Best regards, Rainer.

Please check various grounding points, especially the battery's grounding cable.
Such problems can occur due to voltage fluctuations and brief power outages, and no error will be saved (since there is no power).

@Rainer:

Quote:

What surprises me is that without power to the engine control unit, the glow plug light shouldn't illuminate.

It can happen when the engine control unit (ECU) receives power again after a power interruption, and the check conditions are found to be normal (like during a warm start, where the glow plug indicator briefly illuminates).

Hi.
I will check the mass points again. Since this post, the error has not occurred again, which is, of course, typical .