Hi all, we have a 2013 SD4 HSE and just got a caravan (about 1.8T fully loaded, so well within towing capacity).

The issue I'm having is that after about 15mins of towing, the car seems to be entering some kind of electronic torque limiting mode.

Temps seem all within limints.
- Engine coolant 85*C
- Tx oil 95*C
- IAT and fuel are both around 40*C
- Locking mode is on
- Torque limiting says 2000Nm (which I understand to be unrestricted)

No codes on dash.
No codes on OBD2 reader.

Park the car up for 15 mins and its perfectly fine again.

In the worst instance, I unhooked the van and the SD4 struggled to get off the line, almost stalling.
TX oil only about 20k kms old.

Any suggestions would be much appreciated thankyou!

Update for this is that the txn oil and fuel filter are both only 20k kms old.

Have you treid manually selecting first as the car normally sets off in second unless it detects a trailer is connected. This is where coding a towball/lights helps, as opposed to just fitting them and not coding them?

The only time I had similar expierience to this was due to a patially blocked radiator, the engine temp was still around 90C but the transmission was cooking, which in the UK is good going. Been off-road in clay a "few" times and there was roughly 30% of the radiator not baked in pottery. Baked on clay doesn't jet wash off. Tangiers Orange - gone, missing her
Replaced by Ewok what a mistake - now a happy Disco Sport owner

Thanks Andy, I don't have the trailer coded it seems. Tried manually from first but still sluggish.

Had my mechanic out this afternoon and the car is running rich. He thinks it might be intake related.

More investigation to follow.

It's a diesel, so if it's running rich, there's a lack of air. Look for leaks in boost hoses.
Also if power is limited when it's hot, it could be due to an aftermarket fuel filter.

Also I wouldn't expect good acceleration with an 1800kg trailer on the back. The max towing capacity is 2000kg, so you're only 10% under the max limit. It would accelerate much more slowly with double the vehicle mass too move. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, the daily driver.
1972 Hillman Avenger GT, the project.

Diesel running rich, could be the butterfly valve in the air intake restricting the air intake - mine did with no fault codes.
Could be the air filter, there was an issue with the airbox drain valves improperly fitted / missing that allowed the air filter to become sodden after wading.
On your model are there swirl flaps in the intake manifold? these have been known to fail, common fix was to whip the manifold off and destroy (remove!) the flaps - if they do break with age, they find their way into the engine, not pretty. Tangiers Orange - gone, missing her
Replaced by Ewok what a mistake - now a happy Disco Sport owner