Speed ​​jumps when the car brakes

Vehicle cuts out when braking while driving

Hello everybody,

I have the following problem with my Opel Astra H 1.9 CDTI automatic and hope that you can help me:

Since I have had the vehicle, it sometimes happens that the vehicle cuts out while driving. Usually the problem occurs rarely and mostly when you have to brake a little harder. And by braking harder, I don't mean how to brake if something runs in front of the car or something;) Then I switch the vehicle to N and turn it on again, which works without any problems. In the past, this problem only occurred when it was very warm and the air conditioning was on and you steered at the same time. Corrects me, but this would suggest that the vehicle needs too much power at the moment, which it does not get at the moment and therefore runs out. The alternator was already defective and was replaced. In that case, however, the vehicle didn't even start. The battery is also over every 2 years and has to be replaced. I don't know if that means anything. The previous owner already had the problem (I suspect) because the EGR valve was also changed twice according to the invoices. Oh yes: and at the first start in the morning he always nags himself a lot. If the vehicle was then on and running, it starts normally and without any problems. It has already been tested by the manufacturer's workshop and nothing could be determined straight away. Among other things, it was tested whether consumers empty the car. I once had the feeling that the screen of the navigation system had flickered even though the cart was already out and locked there. But it seems to be normal with some models.

So far I have been able to live more or with the problem. Yesterday, however, it was the case that the vehicle in the left lane on the track simply went out. So hazard warning lights on and on the hard shoulder (thanks, that one was there). So gear back to N, switched on and on. Briefly thought that he had switched to an emergency program, like when the DPF is full. But since it drives normally again after a restart, I don't think it's the DPF, since the previous owner already had the problems (according to my guess - see above).

Today after work I got in the car and turned the key to 1 (or whatever) so that it would glow. I always wait diligently until the light is off (and a little more) before I turn on the tractor. Today he nagged twice briefly and everything was gone, as if the battery was flat. Then close again to 0, then to 1 due to preheating and then started normally via position 2. After about 10 km I went down a serpentine and then had to brake and turn into a street. What happened then? Correct, he went out again. After I broke one off without making the curve without steering assistance, back to N, restarted and geezed the remaining 40 KM home without any problems.

As I said, I would be really happy if someone has a comparable problem (of course I'm not happy that someone has the same problem: p) and can give a recommendation. Since the vehicle is no longer so great, it is no longer worth investing huge amounts of gravel in diagnostics and repairs.

And for everyone else: Sorry for putting such a big story down here. And respect to those who read and understood everything :)

Many greetings and thanks in advance

Die Becky

Similar issues
31 answers

Error codes are always important as a first point of reference! How you can read them out yourself is in the FAQs up here! Please do that first.

Dying diesel engine is funny. Would you then guess that there is a defective glow plug or too little diesel / diesel pump.

But first wait and see what the errors say.

@ masterjäger

Glow plugs certainly have nothing to do with it if it goes out while driving. At best, that would explain the mess at the beginning, but there is no question of glowing lights.


If the battery runs out every two years it is definitely not normal. For me it all reads as if there was suddenly little power while driving. Has the charge regulator been checked before?

I would rather look for the fault in the electrical system. Was the LiMa changed when the car was already in your possession?

Be careful when reading out the error codes, only engine-related ones are displayed, but their appearance may have another cause.

My guess:

The previous owner had already been annoyed with the car, and then sold it when the errors became too many / unrecoverable. Was this pointed out to you at the time of purchase or was it a dealership purchase?

No diesel will run out because of defective glow plugs.

No error codes?

The first thing to do would be to remove and re-solder the throttle valve (it closes during overrun and may not open again quickly enough).

EGR could also cause something like that (how long ago was the last change?).

Then it continues with live values ​​(rail pressure, air mass, ...).

Greetings Metalhead

So first of all sorry for the late reply. But you know that ... somehow found no time.

The history: the vehicle was a company car and everything was always repaired / attempted to repair. When the company car uter got a new vehicle, I struck. I had access to all invoices etc. and could also see that the AGR was exchanged. I know it's not the best vehicle, but I got it for a very good price.

The alternator was last changed in 2012. If it were defective, correct me, the box wouldn't start again, would it !?

I then read out the error codes:





P0606 control unit defective

P1120 Bank2 Probe1, Heater Circuit Open

P1122 Bank2-Probe2, heating circuit interruption

P1700 Brake pressure switch-F270 implausible signal

delete all, look again what comes again.

As such, the story has something to do with negative pressure. Many Z19DTH have massive jumps in speed when braking, yours even seems to run out.

I don't really have it in my head now, but I can remember so darkly that there was something out of that direction.

Cool, that would really go in that direction. Can really confirm that felt. The automatic shifts from the 6th to the 4th and then also brakes the engine. Strangely enough, it is no longer like this from the 4th and it then goes completely into the "disengaged" state. The situation is similar when braking. He "disengages" and the speed goes down to idle. And then sometimes I have the feeling that the drop in speed is too strong that it no longer catches up. Do you also remember what can be done about it?

Oh, and how do you delete the error memory? ;)

With an Opcom or Tech2 (Opel).


@ steel234 wrote on April 1st, 2017 at 8:53:50 PM:

Many Z19DTH have massive jumps in speed when braking,

Since the Z19DTH on the Astra H was never available in combination with an automatic transmission, it has to be a DT with 120PS. DTJ and DTL were only available as switches.

And P1700 is not brake pressure switch like above, but:

P1700 Service indicator light request from the gearbox control unit

Also P1120 and P1122 do not match!

P1120 Accelerator pedal sensor 1 signal too high

P1120 Accelerator pedal sensor 1 signal too low

P1120 Accelerator pedal position 1 sensor out of range

P1120 Accelerator pedal position 1 and 2 sensor incorrect ratio signal

P1122 Accelerator pedal sensor 2 signal too high

P1122 Accelerator pedal sensor 2 signal too low

P1122 Accelerator pedal position 2 sensor not in the target range

P1122 Accelerator pedal position 1 and 2 sensor signal incorrect ratio

So the problem will come from the accelerator!

There are also several codes for P0606, so you should know the exact one!

Replace P0606 control module

P0606 capacitor voltage 1 voltage too low

P0606 capacitor voltage 1 voltage too high

P0606 Control module malfunction

P0606 System voltage too high

P0606 control unit re-initialization

However, P0606 could be a consequence of the fault in the accelerator pedal! I would start with the accelerator to find the fault!

So, 6 weeks ago the accelerator pedal sensor (only as a whole pedal) was replaced for a mere 320 flakes. Apart from the fact that accelerating is a little more difficult than with the pounded pedal, everything is fine so far. The suitcase never ran out. But datt doesn't mean anything at first. I am only convinced when a year has passed without escapades.

For now, thank you very much for your help. Hopefully I will not get back to you with feedback until after about a year.

If something happens again beforehand, I will take the fuse box apart and clean it (WD-40 should work wonders there). I read somewhere that it could be because of that. Again, I will report back.

Hello Becky,

is there anything new on the subject? Did that fix the problem?

I have exactly the same problem with my friend's Astra H (Z19DT with AF40, BJ2007), but without any error code.

Even after going out there are none.

The only thing I noticed was that the transmission control unit software was updated and that of the engine control unit was not. Can there be problems here due to different software versions?

I've already re-soldered the throttle valve, and the EGR valve has already been replaced. Neither resulted in any change.

Thanks and Greetings,



at some point the car didn't start anymore. The yellow angel said that this was a known problem and opened the fuse box and drained it. Liquid had collected then.

As already mentioned, the fuse box seems to be the evil. I also read that you should open the fuse box and gently press the contacts together, as the contact can sometimes be lost. I'll take a look at the fuse box after my vacation.

So take a look at the fuse box to see if it has accumulated moisture and check the contacts.

Please let me know if it helped you.

I wish you success.

PS: here is the link under which I read about the fuse box:


Hmm, I almost ruled out water in the fuse box (engine compartment) because I had it outside before.

But I'll still take a closer look at it after my vacation. At the same time I bought another, used throttle valve and want to exchange the two electrolytic capacitors there.

The box has had the problem since I got it (started with approx. 110 tkm, now 175 tkm) In the beginning, however, only when braking hard. If it is really warm outside, the error now also occurs in overrun mode.

Somehow it almost feels like bad application to me. Maybe because there aren't very many Z19DT with automatic. With switches, the problem we have here is probably not even noticeable.

PS: I also looked at the topic from the link. The control unit plug also seems plausible to me, since the ECU in the wheel arch really gets dirty.