Older thread, but I just had same problem yesterday at around 9000’ on trail near Wold Creek Colorado.
loaded with 3 adults and 2 11 yr olds. Engine usually always get hot at these elevations, so I previously installed a pusher fan on front or radiator and helps tremendously. But, we had stopped for a break, and I turned fan off. As we headed back up the hill, I forgot to turn 2nd fan on. After a long, steep hill, I looked down, and both the high temp and low oil pressure lights were on, as well as 4 bars on the display. I had previously installed and in-line digital temperature readout on the radiator hose, but I think it is on return line going back to engine. Anyway, the temperature was reading 232°F (Highest I have seen it). It usually runs 190-205. I Turned the pusher radiator fan on, and stopped for a little bit, and temperature came down to normal, but took a little longer for the water temp and oil pressure lights to turn off. We turned around and headed back down the trail. I then noticed the EPS light was on, and would not shift out of first gear, either in high or low range. And then noticed the speedometer stayed on zero.
So, began heading downhill. Then noticed that when I let off the gas pedal, the transmission would into neutral, and I would coast downhill. NOT GOOD! But, if I gave it a little gas, the transmission low gear would kick in and slow me down. Now, that takes some coordinatio, to give it gas to slow down. But, after a while, I began using the brake to slow down. But that did not last long, as my brakes must have got too hot, too, and failed. I could push the brake pedal to the floor and bottomed out, and no slow down. Got interesting, to say the least, going down a steep mountail trail with not much room for error.
But, after a few minutes of more riding, and trail leveling out, the EPS light went off, the speedometer began working, the transmission began shifting, and the brakes came back. Everything was back to normal again.🤔
So made it back to trailhead safely, but wondering what the heck just happened.
I will be replacing brake fluid today after reading more about fading brakes. And after reading this post, I think there is really nothing else to do, other than remembering to turn on fan(s) when riding mountain trails.
I said ‘fan(s)’, because I had also installed a small 4” fan under the seat, next to the front drive shaft, taking air from around the front diff, under floorboard, and pushing it towards exhaust manifold area, hoping to keep engine and seat cooler. Never worked very well, but now knowing about the overheating under the seat causing the ECU to overheat, I will use it all the time.
Sorry for this long novel, but it is not something easily explained, and I had never heard of this happening before, until now.
