Vectra's Triple Trouble: Overheating, CEL & Warning Lights

Hey there! I had a similar issue with my 2000 Vauxhall Omega (diesel) last year. I've got some experience working on cars, but this one had me stumped at first. My symptoms were pretty much identical to yours, engine light, overheating, coolant issues. Turned out the cable connection to the water pump was faulty, causing communication errors. Took it to my regular workshop, and they diagnosed it pretty quickly. The fix cost me around 155€, and it's been running perfectly since. Before I can give you more specific advice, has the coolant temperature been fluctuating? Are you noticing any coolant leaks? Which engine variant does your Vectra have? These details would help me understand if you're dealing with the same problem I had. Cheers!

Thanks! My mileage is at 103368 KM and had the last service about 6 months ago. Yes, the coolant temp has been all over the place lately, especially during longer drives. Haven't spotted any obvious leaks under the car, but the coolant level keeps dropping mysteriously. I'll check out that water pump connection you mentioned, sounds like it could be the culprit. Hopefully it's something simple like in your case. The repair cost doesn't sound too bad either. I'll get it looked at this weekend and let you know what they find. Cheers for the help!

Hey again! Thanks for those extra details, definitely sounds familiar to what I went through. Since you mentioned the fluctuating temps on longer drives, that's exactly what happened with my Omega before I got it fixed. Just to share a bit more from my experience, I initially thought I was losing coolant through a leak, but like you, couldn't spot anything obvious under the car. Quick tip: before you take it to the shop, maybe check the connection to the water pump yourself if you're comfortable doing that. In my case, there was visible corrosion on the connector, which was causing the dodgy readings. If you see anything similar, it'll at least give your mechanic a head start. By the way, after my repair, I kept an eye on the coolant level for a few weeks just to be sure. If your issue is the same as mine was, you should notice the coolant level stabilizing pretty quickly after the fix. Keep us posted on what they find, always interested to hear if it's the same gremlin I dealt with! Stay safe on the road!

Thanks so much for all that detailed info! It's really helpful to hear from someone who's been through the same thing. I had a quick look under the hood this morning and, would you believe it, I can see some nasty corrosion on that water pump connector you mentioned! I've booked it in with my mechanic for Saturday morning and showed him the photos I took of the connector. He seems to think you might be spot on with the diagnosis. Fingers crossed it'll be a straightforward fix like yours was. Really appreciate you taking the time to share your experience, you've saved me a lot of worry and potentially some cash too by pointing me in the right direction. I'll definitely keep an eye on the coolant levels after the repair, just like you suggested. Thanks again. You've been a huge help!