Defender Puma 2.4 tdci power loss in 6th gear

[ClaudeG]

@Montari

My one was performing without issues in town and dirt road driving, but once you hit the open road, doing like 120 km/h, it had the same symptoms as yours.

I knew the loss of performance was due to it going into limp mode, but why?

I only figured it out when I had someone drive it and I sat passenger with my diagnostic tool, keeping an eye on live data. I noticed the coolant temperature going up and then when it reached a certain temp, it would go into limp mode.

While this was happening, the temp gauge did not move from its normal position. In fact, I’ve never seen the temp gauge gradually climb when there’s an overheating problem, it always goes from normal position all the way into the red in an instance. Not sure why it's like that, but it’s not very helpful. The way the temp gauge functions, basically just tells you “ok now it’s too late” it already overheated.

Anyway, after that, I went through the coolant system and found the radiator to be dirty, grass seeds etc. Cleaned it properly and made sure I bled the coolant system properly and correctly (this is very important) and in my case it sorted the problem out.

Good advice! If the cooling system is fine after checking, could be a bad map still. Maps cause temps to accelerate in high gears pushing pumas into limp.