Gearbox Overheat (again!)

P38_OTMS said:

I know this has been covered over and over again but no-one seems to have my specific issue.

Ever since I’ve had the car the gearbox overheat warning comes on as soon as the key is turned in the ignition - therefore clearly isn’t overheating.

I’ve changed the sensor, no change. Checked the wiring, all seems ok.

Brand new battery too so it’s not the weird low battery fault.

Just wondering if I need to do some sort of electronic reset to make the message go away? Or have I got two duff sensors?

Thanks!

James

Click to expand...

P38_OTMS said:

I’ve just blasted the connections with contact cleaner so looks like two duff sensors...

There’s no fuse or relay or anything relating to it? Assume not but if you don’t ask...

Click to expand...

P38_OTMS said:

Just tested it with resistance on the multimeter and it appears both sensors are open circuit.

I really don’t fancy chasing wiring all through the car... hopefully it’s the plug

Click to expand...

P38_OTMS said:

Yea haven’t got contiuity on my DVM. Will see if I can borrow one locally

Click to expand...

• Sensor unplug immediately triggers warning message, and also shows in Nanocom BECM Inputs as expected.
• DVM measure across sensor wires shows 0.4 ohms (meter reads same with probes shorted) when sensor working. Wiggling wires sends DVM reading to >> MegOhms. Sensor wires are duff, so gonna replace.
• Cooler input & outputs measure approx 50degC & 35degC after 10 minute drive, so fluid not overheating.

pwood999 said:

Also got problem with sensor on my transmission cooler. In my case the wire seems intermittent where it enters the sensor plastic body. I can trigger the dash warning just by wiggling the wires.

Bigger issue is one screw has snapped off, and the other will not turn. Squirted it with plus-gas and waiting for rain to stop so I can try again. Cooler looks like there just enough space on either side of the frame to carefully drill two new pilot holes for replacement sensor screws.

View attachment 179356

Click to expand...