How to repair a MK5 Golf with Brake Pressure Sensor G201 Failure
If your car has FULL service history go to the dealer. I believe this procedure is done for free. You can at least enquire about it even if you car has partial history. You may be able to get it done on goodwill which could save you some of the costs involved.
Now, after owning my Golf for coming up 2 years, this is one of the points of failure I have recently encountered. For reference my golf has had full dealership history up to 39,000 miles and the sensor failed around 54,000 miles. Take it how you will, this may not be the lifespan, just bad luck. If you don't like this guide, you can read the original guide I found on the net the most useful for understanding and rectifying the problems by reading the G201 Repair Article on the Briskoda Forums I give all thanks to the original editor of this guide because this is the best one I've read on the net by far and where I based my decision to write this guide in my own words.
Now to summarise for those reading this document, you will need to purchase a brake sensor repair kit. It's best to call the dealership and give them the chassis number or registration plate of your car. The parts tech at VW told me there's 4 types of pump that fit that are fitted to your car and the registration will identify it. For the purpose of this guide the repair kit I used for my car was part number 1K0 698 517 B which was £160.68 from the dealership or £167.06 without the discount applied by dealership for me.
The price to carry out this entire repair was in the region of £200 including the sensor and all the parts required DIY and took around 1.5 hrs total from replacing the sensor to carrying out the draining of the brake fluid. The garage repair time is around 3 hrs, so beware of paying a garage/dealership for this repair. You are looking at the cost of the parts/supplies and the labour time of 3 hrs+ @ maybe £60 per hr. So you'd be looking at a repair bill of maybe £400+ so think carefully which option you choose. If you're a decent spanner monkey and have access to the tools DIY it. If you're not confident or skilled enough, find a friend who is. The last option is go to a garage/dealership and see if they will do it on goodwill.
What does a G201 Pump ABS Unit like?
The item will be under your battery and have all the steel/copper pipes going to it from your brake calipers. It will look like the below picture
STORES AND SUPPLIERS FOR REPARING
If for any reason, you aren't confident in identifying the part for this repair yourself, I've compiled a list of some eBay sellers who will be able to review the information you given them and provide you with the kit you need to carry out the repair on your car.
Or you can use these links to buy the part direct (1K0598617B) - I recommend checking to make sure your part fits as you may have a different variant on your vehicle. I have used neither of these sellers before so would appreciate feedback on them. Their feedback scores seem OK, the only option if you want a brand new pump is spending the money as you can see the prices are vastly different.
Please note - the following links are affiliate links, you don't have to use them, but it is appreciated as it helps me with hosting costs and articles
If however you are comfortable reparing and identify the parts you need for your car yourself, you can use a generic search time on ebay such as VW ABS PUMP and pick the part you need
Symptoms of a failed G201 Sensor
The most common fault is that the ABS/ESP light will permanently turn on and not turn off disabling the ESP functionality of the car. You will also not be able to turn off the function by using the button surrounding the ashtray for the ESP. These cars also handle like crap without ESP but I think that's just my opinion. You can double check the sensor has failed by hooking up VCDS/VAGCOM to your OBD port in the car. Going into the ABS Brake individual controller and selecting group 5. The value should be reading a maximum of 4 bar of pressure on the brake pedal when pressed. I concluded my sensor was busted when the sensor was reading 200+ bar of pressure without the pedal being depressed.
If your car is reading as 4 bar maximum, then check out other fault codes on the car. The ABS/ESP light can also light up on Volkswagen cars if there's a problem with the brake/wheel speed sensor, although this normally shows up when you're trying to perform the steering rack calibration and it won't disable the yellow steering wheel light or shut off the ABS light. This normally means there's a fault detected
Pre-requesites required before repairing the G201 sensor failure
Purchase the repair kit {obviously}
A laptop and VCDS cable {for purging the ABS, apparently it's possible without, but I didn't want to risk it - although when/if I find the method I will document it}
An ample supply of brake fluid {DOT4 - some sites say you use up to 1Litre and some sites say using VCDS expels up to 4Litres, so I just bought 4 to make sure}
The code for the Car Radio {just incase}
Tools required for the use of repairing a failed G201 brake pressure sensor
Selection of spanners {10-15mm in size} - for opening the bleed nipples on the pump and the brake calipers
Selection of sockets {10-21mm in size} - for removing the battery clamps, battery tray and wheel nuts
Pliers - for squeezing the hose clamp holding the air filter/MAF pipe in place
Phillips Screwdriver - for removing the screws holding the AIR FILTER in place
Wheel Removal Tools {vehicle jack, centre cap remover - or screwdriver, wheel lever, locking wheel nut remover, axle stands, breaker bar for leverage if needed}
Torx/Allen/Hex Sockets - for removing screws holding ABS pump {think it's T25 for the pump} and the Air Filter Housing {can't recall this one
If you don't have sockets, you can purchase a cheap key Set from Machine Mart. You can find a cheap one here, the one I personally have isthis key set
OPTIONAL TOOLS YOU MAY FIND USEFUL BUT NOT NECESSARY
Empty pop bottle or funnel {you will find these extremely useful when topping up the brake fluid. Unless you like the fluid all over your engine bay}
Pressure bleeding kit such as Gunson's Easybleed
Procedure to replace the failed Brake Pressure Sensor
Pop the vehicle bonnet lock and wind down the window - just incase the central locking locks you out. Call me paranoid OK....
Open the battery cover and disconnect the clamps holding the battery in place and remove battery
Remove the screws from the air filter and the tubes holding in place. Also loosen the clamp at the rear of the pipe and disconnect and move it out the way
Remove the battery tray {you will need to maneouveure it around the earth cables} - it's held in by one nut I believe and a couple of poppers
Remove the lower half of the air filter housing - one nut and a couple of poppers
Once the above are removed, you will have visibility of the actual ABS pump and sensor themselves, it will be a unit held in place by 2 screws and 6 pipes
Wedge a stick on the brake pedal to close the brake ports on the ABS unit (put a brick under pedal to stop it going to floor if your paranoid)
Remove the screws to the ABS housing (one long underneath and one short at the top)
Disconnect the electrical connector to the ABS pump housing {you may find this easier once everything has been removed} - it's on a special latch
Remove all the brake union pipes to the ABS pump remembering their locations {picture will be added soon} and remove the unit. You can plug the ports if you want, depends how much mess you like. The repair kit includes all the stoppers to put into your old pump to save mess
Carefully remove the entire ABS pump from your vehicle, disassemble the broken housing from the pump it may require a bit of force but should seperate with no tools
Open up the repair kit bag, taking care with electro static discharge and swap over the broken unit with the repair unit. There is a little "fork" that aligns with a hole inside the repair kit but it's fairly easy to get into place
Once the repair kit is installed, install the new screws from the repair kit (or use the old ones) - torque them to 8+2Nm {or tight then a slight bit more}
Swap over the mounting if needed at the bottom of the ABS pump (it may have come off on removal) it's a piece of metal with rubber stops)
Refit the newly repaired kit to the car and reconnect the electrical connector first (mainly just to avoid any residue, dampness, etc) make sure it sits in the holes
Slowly, methodically and carefully reconnect all the brake pipes to the housing in their correct locations tighten pipes to 13-20Nm, keep them square and DO NOT cross thread them. Or you will bugger the repair kit (if you do you MAY be able to helicoil the kits, but I doubt it personally)
When the pump is replaced replace all the previous parts removed in sections (2-5) and refit the battery
When you reconnect the battery, the alarm is most likely going to go off. Be ready to "open" the car with the central locking or put key in ignition this completes the section regarding the repair and replacement of the failed ABS pump for the G201 sensors. The next section will be for the ABS "bleeding"
Procedure to pre-bleed ABS pump and Brakes
Before I start with this section, this is just the procedure I did with Steven. There are multiple documentations on how to pre-bleed the ABS pump and the system, so take it what you will. You may want to do it your own way, but I have my theories over the way things were done and that's what I'm sticking to. This procedure is really best left to do as part of a two person job otherwise you will get sick of going in / out car and opening/closing valves.
A lot of documentation on the web refers to the ABS pre-bleed as using 4 litres of brake fluid. I didn't use anywhere near that much, the thing about the ABS pre-bleed is that the procedure is merely meant to refill the ABS pump and push all the air out of the front bleeders and refills the car with new fluid. So I didn't go through the procedure all the time, just enough to cycle the fluid and refill the pump. Your choice how far you go.
Put your car keys in the ignition and put your engine into accessories position
Hook up and launch VAGCOM and clear the error codes (the error code disappeared for me but left me with a G85 Steering Angle Sensor fault) - fixed later
Remove the wheels at the front of the car and open the bleeder valves on both sides at the same time
Open VAGCOM and select the "ABS Brakes" option. Go the "Basic Settings" on option 4. Then depress the footbrake. Go to group 1 and click go.
VAGCOM will then run through a procedure to bleed the Hydraulics REMEMBER TO KEEP THE BRAKE FLUID TOPPED UP!!!!
What this procedure is essentially is the same procedure you do during a "2 man brake bleed" with the conventional method. Basically you hold your foot on the brakes, then open the bleeder valves. VAGCOM then cycles the pump (which pushes crap loads of brakefluid out the car), you then hold your foot on the brakes and get someone to close the bleed valves. You then pump the brake pedal to get pressure. You then put your foot back on the brake, and open the bleed valves and cycle the pump, then close it. You keep repeating this procedure as necessary. I did it about 3 times.
Once you're happy they have been bled, you can carry out your normal ABS system bleed. By holding your foot on the brake. Opening the valves, closing them. Pumping, Hold brake, open valve, close them, pump them. Do this about 2-3 times for each wheel and pump about 5-6 times each time. When you start engine give the brakes a quick pump up and then they should be hard and you should stop
I've read multiple sites about the procedure for ABS/Non-ABS cars. I originally thought the procedure was RR, RL, FR, FL (furthest from pump to nearest) but lately I read it was FR, FL, RR, RL (paired lines). I'm not 100% sure on this so do your own research to make sure. The procedure I used was FR, FL, RR, RL
If you drive a petrol and hold your foot on the brake I believe it stays there. On diesels they sink, it's something to do with the way the vacuum system works (either that or your master cylinder is busted) but as long as the car stops when you stamp on the brakes you should be OK
Now, before I finish I mentioned when I cleared the fault codes on the car. I had a G85 steering angle sensor fault which lit up the light on the car. This is because the car doesn't know which way the wheels are aligned. If you don't sort this your tracking will be out and it will eat your tread. Mine actually fixed itself once I started driving around 50 yards or so the light and error code disappeared. So I didn't need to carry out the below procedure. You will most likely find the error disappears once you drive the car a short distance
This is the short part of the calibration procedure the full procedure is documented on the Ross Tech Wiki but basically you logon with the operating group in VAGCOM for steering and check the measuring blocks then adapt them. With the engine still running you carry out the following procedure if required
Center steering wheel (±10°) and hold it centered for 5 seconds.
Turn steering wheel completely to the left and hold it there for 10 seconds.
Turn steering wheel completely to the right and hold it there for 10 seconds.
Center steering wheel (±10°).
Switch OFF engine and ignition.
Switch ON ignition.
Wait 5 seconds.
Steering Assist Warning Lamp should turn OFF. If it doesn't, perform a short test drive.
