940 & 960 940 coolant temp sensor "fault"
1991 940 with B230, LH Jetronic 2.4
The car regularly sets a fault code for the Coolant Temp Sensor. The fault can be reproduced almost every time I drive the car.
Scenario: I live on a mountain with a roughly 4km long climb. Most of the climb I have the throttle at 3/4 to wide open. The code will usually be set when nearing the top of the climb or just after getting to the top. It also occasionally sets the code when accelerating at other times such as moving away from a standstill at traffic lights which it was it did this morning. Ambient temperature has no influence on the problem. Whether it's hot or cold outside the fault will occur.
This has been ongoing for many months. I installed a new Bosch coolant temp sensor early this year but it hasn't fixed the problem. A few weeks ago I removed the inlet manifold to get to the plug. I sprayed contact cleaner into it, tried to tighten the female connectors by pressing down on them with a small screwdriver then applied some electrical grease. This stopped the problem for about 2 weeks but then it returned. Last week I unplugged the connector then plugged it back in again and wiggled it around a bit and the problem stopped for a couple of days but then returned.
I've just been resetting the fault at the diagnostic box in the engine bay when it occurs but that's become tedious and annoying now so I want to try to fix it.
Based on my previous attempts to fix this it seems to be a loose connector causing the problem. Is there any way to tighten them more effectively than by the screwdriver method that I've already tried? I'm also wondering if replacing the female pins in the plug might be the way to go. Is there possibly some other cause for this I may not have thought about?
Thanks for any input.