Bipper preheating lamp issue

The symptoms you're describing suggest a potential issue with the preheating system. A defective preheating control unit aligns with the illumination of both the preheating and check engine lamps, as well as the observed smoke upon acceleration. Before condemning the unit outright, have you inspected the wiring harness and connectors associated with the preheating control unit for any signs of corrosion, damage, or loose connections? A thorough visual inspection, followed by a continuity test of the wiring, might reveal the root cause without needing immediate component replacement.

Thanks for the quick reply! I did a quick look at the connectors, but didn't do a continuity test. Can you tell me more about how to do a continuity test, and what readings I should be looking for?

Given your observations and the preliminary checks you've performed, it is increasingly probable that the preheating control unit or its associated wiring is the source of the problem. While further diagnostics could be pursued, considering the age of the vehicle and the cost of components, I would strongly suggest visiting your local mechanic. Based on the symptoms you've explained, you can expect a repair cost of around 95€.

Thanks a bunch for the advice! Took it to the shop, and you were spot on. It was indeed the cable connection to the preheating control unit. They cleaned it up and it's all good now. Cost me 95€ as you predicted!