Hello friends, the topic “Terrain Response System faulty” has been mentioned here quite often.

I don't have any error messages (unfortunately), but I've had the feeling for over a year that something was wrong with the system.

Problem: I start the car and it drives normally. The next time I start it, it drives sluggishly and lamely, as if someone is holding the car. The throttle response is delayed and the engine runs hummly.

The next day, everything is back to normal or bad again. Pure coincidence, you can't reproduce it.

This morning: The car was running very slow and strained again, delayed throttle response. As if there was a heavy trailer hanging on it. At the traffic lights I then selected the various TRS programs, no improvement. But: In the “Sand” program, the car ran like a Porsche, totally light and agile. Back in the other programs: Tough and lame, even in the standard “Street” program.

I then googled and found a video where someone pulled the plug from the pressure sensor on the throttle valve and plugged it back in when the TRS error occurred.

This is what I did: unplugged it. “Low engine power” error. Plug in, error gone. Car runs like new with power without braking feeling!

Is it possible that some sensor delivers poor values depending on the day or the weather? ABS sensor, ABS ring, ESP System or something similar.

What if an ABS sensor delivers a value where the car “thinks” a wheel is spinning and therefore switches on the all-wheel drive and reduces engine power. Would that be plausible? Because I mean, this wheel monitoring is switched off in the "Sand" program and that's why the car drives light-footed and agile on the road.

The error memory shows nothing when I read it.

Thank you very much and kind regards!

PS: Sorry for my English, sometimes I use Google Translate

I would be checking the throttle body. It's not uncommon for the plastic gears to strip, giving inconsistent air flow to the engine. If the ECM doesn't measure enough air via the MAF, then it'll limit the amount of fuel delivered to the cylinders.
It's not a TR issue, just that TR requests a different power curve map be used in different settings. In sand mode, the throttle is held fully open, and EGR is closed to ensure maximum torque is always available, increasing throttle response.

If a sensor is unplugged or faulty, EGR functions are terminated, and the throttle will again be opened fully. The fact it works better after sensor disconnection to me is pointing to the throttle body being faulty. 2009 Rimini Red SE TD4. Soon to be sold.
Hyundai Ioniq 5 Ultimate on order.
Gone. 2006 Tonga Green i6 HSE.

Hello Nodge68,

I am very pleased with your answer!

I've actually suspected the throttle valve for a long time. That's why I rebuilt all the sensors, removed it and cleaned the housing (full of black dirt). And closes the EGR-pipe with a plate (with a little hole).

When the car runs poorly, I also have the following symptoms:

- Delayed throttle response (1-2 seconds and then go)
- Sluggish acceleration
- Jerking
- Hummy engine running
- Low performance
- High diesel consumption

But shouldn't an error then be displayed?

Does a defective throttle valve also affect the turbo or VTG control? And also on the EGR, as you write?

Thanks alot!

Nodge68, one more question. The plastic gear is even available as a spare part for just 10-25 euros/pound.

Should I order this and test it?

I'd take the side cover off to prove the gears are worn. However if there is an issue with damaged gears, then I'd replace the whole assembly, as the feedback potentiometer will also be worn, which can't be replaced.
Also a replacement throttle body requires calibration using suitable diagnostic equipment. An uncalibrated replacement throttle body can also give symptoms of a failure one, so any replacements need proper calibration. 2009 Rimini Red SE TD4. Soon to be sold.
Hyundai Ioniq 5 Ultimate on order.
Gone. 2006 Tonga Green i6 HSE.

just a thought,if i use heated seats or heated screens when i start ,on a very cold day,when battery is very low,we get reduced performance,no warning on dash,stop and re start and back to normal.so we leave charger on,or start car 10mins before to charge battery.

Yes, I agree. A new throttle body from Pierburg costs around 110 euros/pound.

I have JLR SDD for programming , so far no problem.

I drove again yesterday afternoon. The car ran well at first, then very badly again. Delayed throttle response and sluggish, buzzy, loud.

I then switched TR from “Street” to “Sand”. And the car immediately ran better. Much quieter, faster, you could say: normal, just as it should be.

I'll test it and report back!

Hi. Have you fixed or diagnosed the sluggish problem? I feel I have the same problem with a delayed acceleration. Thank you.

Hello, unfortunately I haven't made any progress yet.

Since I unplugged the pressure sensor and plugged it back in, the car has been running very quietly and 90% better than before.

The throttle body doesn't make the noise it's supposed to make when the little gears are broken. No errors in the ECU either.

But what strikes me is that I've been hearing a whining noise for some time now, like a dry bearing. However, the noise is not always there and cannot be reproduced.

But if the noise is there, the engine is running poorly. But at the moment the noise is not there and the engine runs great.

I want to take a look at the timing belt and tensioner, but I don't have much time at the moment.

I'll let you know when I know something new!