1.2 TDI starting problem

Dear all,

I bought an A2 1.2 TDI about 3 weeks ago (here in Switzerland, where I live) and now I have a problem starting my car since about 2 days. And so I would like to ask you some questions, please.
Whenever I entered the car (before I had this problem) I had to wait about 20 seconds before I could start the engine (I could hear a noise, which now I know it's probably the hydraulic pump for the gearbox, by reading different posts in this forum). First question: is it normal to have to wait this "long"?
The present problem I have is the following: to start the car first I wait for the hydraulic pump to do its job (like I used to), and then when I press the brake pedal (like I must) the "brake being pressed indicator" near the gearbox selector doesn't turn off (light stays on) and I can't start the motor.
Quite often I can overcome this by pressing quickly and with some extra strength the pedal brake (repeatedly), and then I can start the motor and everything seems fine. Note: during this procedure (and before starting the motor) the pedal brake gets "harder" and when the motor starts is goes soft back again.
Sometimes, the triangle warning and ABS indicator in the dash light up and stay on after I started the motor.
I read in this forum that the accumulator in the gearbox hydraulic system might be the source of related problems. What do you think?

I tried the test I read also here at the forum in which I should count the amount of gears I can change in Tiptronic mode (with engine off) before the hydraulic pump starts running again: it's about 2 (I can change from 1st to 2nd and then to 3rd without the pump re-starting).
Note: I can select all gears, without problem (as long as the "brake being pressed indicator" turned off, otherwise I'm stuck in STOP).
Note II: I didn't check what is the level of oil in the hydraulic system because I probably don't have the skills/time/knowledge to do the mentioned procedure given also here in the forum (unplug hydraulic pump connector and do a half-turn of the accumulator with a spanner).

When I bought the car I was given 3 months or 3000km guarantee in motor+gearbox, so I still can claim this problem if indeed it's related to the gearbox. So the other question I have is: do you think it's safe to drive back to the garage (about 250km)? Could my problem instead be related to the brakes (since sometimes the ABS indicator lights up) and I'm risking mine and others lives? :(

Thank you in advance for any help and tips.

PS: I already had a problem with the turbo system and so I had to drive in 'limp mode' all the way back to the garage (thanks to this forum I now know what is 'limp mode' and what probably was the turbo problem). I love this car and I had a hard time to convince my wife to agree in buying it together but until now it has been a bit hard dealing with these problems. That's live ;)
... the "brake being pressed indicator" near the gearbox selector doesn't turn off (light stays on) and I can't start the motor.

The brake light switch might be the cause, they're very problematic, and from what I gather, if you have an automatic and the brake light switch is bust, then the car will prevent you from driving since it thinks that the brake is still applied (or thinks that it has never been applied). Sometimes a brake light switch failure will cause various lights to turn on (glow plug warning light is the most common, the other lights are less common but does sometimes happen).

The brake light switch is roughly £ 10 / euro 12 or thereabouts, and you can change it yourself although it can be a fiddly job.

Note: during this procedure (and before starting the motor) the pedal brake gets "harder" and when the motor starts is goes soft back again.

This is normal - the brake servo uses the vacuum generated by the engine. If you pump the brake when the engine is off, you will lose the servo assistance.

PS I know nothing about the 1.2 specifically, these are just generic answers.
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With the gear selector in 'P', your foot needs to be on the brake pedal, as the brake pedal also operates the clutch. You can also start the engine in neutral without your foot being on the brake pedal. If the first option does not work and the second does, it is likely that your brake switch requires replacement. Not necessarily though as my Lupo 3L would recently not start in 'P'. A basic setting of the clutch/gearbox using vagcom cured the 'problem'. No adjustments were necessary apart from the gear linkage, which is part of the basic setting.

There is nothing to indicate that your accumulator requires replacement. Be aware though that vagcom (VCDS) cannot diagnose a failing or even failed accumulator!

If your brake lights work, it should be safe to drive the car.

Thank you very much MikeMars UK and RAB for your kind help. I have started already looking in the forum on how to change to brake light switch and I might be able to do it myself.
In the meantime, I have checked if the brake lights work and they do. I also can start the engine in neutral (without my foot being on the brake pedal) but to change from 'P' (which is the gear position I normally choose to park the car) to neutral I need to press the brake pedal (which I know it's normal) and that's where the problem lies since sometimes, like I described previously, the "brake being pressed light indicator" near the gearbox handle doesn't turn off and so I can't change gears (and neither the engine can be start). Note: when the light indicator turns off, I hear a small "click" sound somewhere close to the gearbox handle.
RAB, do you confirm that the fact that I have to wait about 20s before I can start the engine, after leaving the car overnight, is normal?
I would like to check the fluid level (after leaving the car stopped at least overnight) of the accumulator if it's something more or less easy to do. Could you give me some hints where to find it? Thank you.
I will keep you updated if I (or a garage) manage to solve the problem.

Important correction to what I said in my last post: brake light switch don't work whenever the "brake being pressed light indicator" doesn't either. So the problem could be a bad electrical wire contact or a bad brake light switch could do the same?
The hydraulic pump should start immediately the driver's door is opened. 20s is a little long but may indicate plenty of capacity in the accumulator, which is a good sign. Pressure can be lost overnight. This does appear to be a brake switch problem.

To check the hydraulic fluid level, remove the bonnet first. Looking from the front, the hydraulic unit is to right, at the top rear of the engine compartment. Unplug the electrical connection and with a 24mm spanner loosen the accumulator by half a turn. The accumulator is a roundish container mounted at an angle. A chain type filter wrench is a useful alternative to the spanner. Check the level in the box-like reservoir; it should be within the 'window' towards the top. Do not overfill. Re-tighten the accumulator and reconnect the plug.

Thank you once again for you advice MikeMarsUK and for your very clear instructions RAB.
I inspected the region near the pedal brake and I found out that I can see the switch just above it, without taking out any panel. Probably I can even remove it directly. Since the switch sometimes works (and now I understand what it is in reality, because I my head it was something like a fuse...) I thought that maybe the problem is that the small "piston" that detects the pedal being actuated is getting stuck in its initial position (i.e. like I'm not braking). So I decided to spray it with some oil (WD-40) and see if it helps. It seems to have helped since now it practically works all the time (it failed once in more than 20 tests and that was just after the spraying). In the meantime I'm going to buy a new switch (just in case) and keep doing some tests.
Note: maybe when the switch is stuck in the initial position and the ECU (or something) detects pressure in the braking system, then the ECU triggers the triangle warning and ABS dash lights (or sometimes gets confused and even triggers the glow light turns on like I saw once?).

Anyway, once I have time I'll check the accumulator and its circuit oil level (OK, now it's clear to me that this probably has nothing to do with the main problem I had but I have the feeling that the hydraulic pump works overtime).


I have a audi a2 1.2 tdi that are starting to have some problems. When I bought it one year ago I made that test to check how many gears i could change before earing the pressure motor and it was normal (about 7 gear changes).

Today when making a steering alignment I noticed a loss of fluid that ccome from the gearbox so I made that tes again... and every 2 gear changes )1st to 2nd and 2nd to 3rd) the pressure pump starts again!! So I have a leakage...

Any idea how I can solve this problem? Can I top up the system with hydraulic fluid (I don't want to stay on the road..) after checking the level?

Most of the spares are available from VW/Audi or here on ebay: http://stores.ebay.de/DER-3LITER-PROFI?_trksid=p4340.l2563

The proceedure is in the Audi workshop manual which can be bought on CD or you can find other threads on how to replenish the fluid. It is best to change the seals on the bottom of the gear change unit and also renew the hyd hoses, O rings and vital clip that looks like a hair clip!

These cars go on if you look after them - one on mobile.de with 400,000 km!
Find out positively where the leak is and fix it. Do not take anything apart unnecessarily, particularly the actuator. The other possibility is that the accumulator is failing: note that the Audi diagnostic system (and Vagcom) are totally unable to diagnose this, resulting in many completely unnecessary replacements of much more expensive components.

To check the level, disconnect the electrical connection to the pump unit and undo the accumulator half a turn. The fluid should be at the top of the 'window' of the reservoir. You might need a torch to see the level. Top up if necessary, re-tighten the accumulator and reconnect the plug.

If topping up makes a difference to the number of gear changes, it's down to a leak. If not, it's the accumulator.


I want to thank you all for the comments you've made on this subject as they helped me to quickly find and solve the issue on my A2 3L.
Same symptoms as Miguel Silva described, engine didn't start, brake pedal light wouldn't go off, after a few attempts to start the engine ABS and ESP warning lights would turn on and I could hear three beeps from the dashboard.
The way to solve it was quite simple, a new brake pedal switch 1J0 945 511 A for 13.55€ (3rd party, inc. VAT), and no need to remove any screw. Spot the sensor, which is actually above your foot when braking, twist it 90deg counterclockwise (bayonet connection), push it back to the interior of the dashboard then rotate it inside the dashboard with the wiring on the upper side and pull it down. You may now access the plug that can be removed by pressing the levers on both sides. If the plug seems to be sticked you may twist it left and right. Connect the new one and assemble it back.
This took me 5min and I was impressed because I even took a T25 screw from the bottom of the dashboard I didn't need to. I was expecting 4h of work and to tear a lot of parts down.
Problem solved so far.
Regarding the faulty part, I noticed it was full of some sticky grease (I bought my A2 it on 3rd + hand) that prevented the slider on the sensor to shuttle back and forth, getting easily stuck when on the most retracted position, that stands for no brakes applied, therefore no engine start.

Hello and welcome... its always nice to hear positive feedback and I,m pleased that the A2OC has been able to help you. Rab is thought of as our resident helpful A2 3L expert and his knowledge has been an invaluable assistance to 3L owners.

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