Test procedures on the trans temp warning light

lordhelemt

Well-known member
Dec 18, 2010
56
3
Anyone know the test procedures on the trans temp warning light?

Light is on even on a cold truck. Learned there was a sensor at the trans cooler and one on the Tcase. Trying to determine which sensor is turning the light on. Unplugged them hoping unplugging the bad sensor would shut the lamp off but with both sensors unplugged the warning lamp is still on. Any ideas?
 

lordhelemt

Well-known member
Dec 18, 2010
56
3
Does anyone know how to test the sensors?

I’ve managed to address and clear all the dash lights except for this one.
 

skucera

Member
May 13, 2014
5
0
Harrisburg, Oregon, USA
I had this problem on my old 2000 Disco 2 about five years ago. I used a laser pyrometer to measure the temperatures into and out of the transmission cooler, and they read about 148° out of the tranny when the light came on, so I figured I had a failed sensor. I read back then that transmission temperature sensors commonly fail on Disco 2's. I've never had one fail on any other car I've owned.

Anyway, I never did get around to replacing that sensor before I sold it to a local farmer, but I warned him about it. The bigger problems with that rig was the cracked windshield, and a collapsed tappet.

Good luck,
Scott
 

gthphotography

Well-known member
Aug 27, 2008
312
3
chicago
www.greghanrahan.com
My 04 had that happen. If I remember correctly, and please correct me if I’m wrong, but I don’t think that we have a working trans temp sensor in the D2. The wiring is there, but there is no sensor in the trans. I found my wires had come loose and were tripping Themselves. I cleaned them and potentially taped them off and shoved them up over the top of the trans. Never had another issue.