When it is raining or really humid air, my Octavia 1.5 TSI jerking during the drive. It feels like it lose power for a milisecond and then drives normaly. Sometimes it will happen only once during drive, but sometimes it will do that couple of times. Beside that, car is working perfectly, no errors and when its not raining, this problem is not appearing.

It is doing the same in every driving mode, with ans without traction control turned on, spark plugs are new, car battery is new. Also I've checked injectors, oil separator, pressure sensor, coils... everything is fine and it left me with only one question: How can rain affect a car?

There is probably moist accumulation somewhere because it's not happening when I drive longer or when it's not first drive in the morning. This is happening ocasionaly for a longer period of time when weather conditions are like this, it's not getting worse/better, just the same whenever it rains.

Car is Octavia 1.5 TSI DSG 2019 with 113.000 km.

Maybe not related but you do not mention the air filter and it being checked and clean and dry.

I'd suggest looking at sensors in engine air intake as a possibility of being affected by rain - although they'd be downstream of the filter.

Has the air filter ever been replaced?

Air filter is changed couple months ago, this was happening before and after replacement. But I'll check it anyway.

I'm having the same issue. 2014 1.6Tdi Octavia with 360,000 km on the clock. Well maintained car and driving very well, but, it does exactly this when wet. No other symptoms, just an apparent loss of power. Dropping a gear or sticking the foot in to try and drive through it doesn't work. The car can go from 100 to 85kph or 120kph to 105kph quickly until it recovers.

My thoughts are:

1. Is it a boost issue, is the turbo or actuator misbehaving and boost is dropping momentarily.

2. Is the DPF crammed and needing cleaning/replacement - I must plug it in to see measureed and calculated soot levels. I seems to regen alot (fans and heat from underneath) so I'm thinking it's this, and there's a back pressure created that's choking the engine...

3. 1 & 2 would happen all the time though, not just in the wet....

4. Is the wet affecting a wiring connection somewhere, but what could be in a position where water would get at it and cause a problem...?

5. Could it be an ABS problem, somehow linked to the hill hold function, that's engaging the hill hold? (maybe I could code out hill hold for a while and see if it makes a difference)

Any thoughts from the wise folk on here are much appreciated.

B

On 25/04/2025 at 17:26, Octavia2019 said:

When it is raining or really humid air, my Octavia 1.5 TSI jerking during the drive. It feels like it lose power for a milisecond and then drives normaly

Traction control....

41 minutes ago, BlueWagon said:

Traction control....

Definitely adding to the list, thanks @BlueWagon Any idea if a VCDS scan should show errors with the wheel speed sensors or module? Yes yes, will plug it in this evening anyway

My Octavia 1.4 (64 Plate) has a possibly similar fault to that on this thread: only when raining, travelling at speed it will regularly (sometimes every 5 mins) suddenly brake hard and pull to the right. Taking my foot off the accelerator resets it and the car will pick up speed again. I have taped over what I think is a rain sensor behind the rear view mirror at the top of the windscreen. However, that has not sorted the problem. Is that actually a rain sensor? Are there other rain sensors I have missed? What other sensors linked to the Braking system can be affected by rain?

That rain sensor on the windscreen is only for the auto wipers, so that will have no effect on the brakes.

I suspect that one or more of the wheel speed sensors is being affected by the rain.

Thanks for the tip PetrolDave. I'll get it looked into. Diagnostics doesn't seem to have revealed anything in the past maybe because they were completed in the dry. Does it pulling to the right indicate that the driver side front wheel sensor is the fault or should I just get them all replaced?

Pulling to the right suggests a right side wheel is being braked - either because a right side sensor is reporting too fast OR because a left side sensor is reporting too slow.

Another thought - is this happening when hitting deep standing water on one side?

Gee PetrolDave, you know stuff! Would make sense.

Warrior193: no, it pulls right when its just raining. Doesn't even need to be heavy rain. Its not the usual brake effect when you hit standing water on one side. Thanks for the thought though.

I'm going to plug the car in as soon as I get a chance and see if there are any errors to read. Is it possible that there are wheel speed sensor faults being logged in the background without dash lights? Or if there was a faulty sensor(s), is the car just reacting to the incorrect information it's being given, and there is no reason for a fault to be logged?

I must also check DPF soot levels as at my mileage it's high on the list of suspects.

30km test spin in the wet at the weekend, 100km cruise and 9 occurances of this issue all spaced evenly throughout the spin. I turned ACS off via the head unit at the halfway point and it made no difference. Wife was driving in the dry yesterday without any issue.

Wet ->problem -> 'probably' speed sensor

Could be something simple like water getting into one of the connectors.

16 minutes ago, ords said:

Could be something simple like water getting into one of the connectors.

Thanks. Will add wheels off and full check to the list

My Octavia's sudden braking and veering to the right issue is still present. My mechanic does not believe it is the wheel speed sensors at fault. He maintains that the diagnostics would report errors, which it is not. He's now wondering if it is linked to the ABS pump and uneven braking by the front brakes. So the car believes the ABS should be applied slightly when its wet to keep the brakes dry, and the fault is then with the front brakes unevenly transferring that to braking the two front wheels. It needs to be checked in the workshop, but it does have a certain logic worth pursuing. Thoughts?

I replaced both front speed sensors which has had no effect on the issue.

@Melnic your comment sounds like a possibility. I wonder if my mechanic will have the skill to run the correct diagnostics on it....

Rear sensors could be an issue, but most likely not. An ABS pump with 360Km on it might be more suspect. I have no understanding how this system operates though so not willing to start troubleshooting