WTF? is ABS, EDL, ASR, ESP, HHC....etc?

[fabdavrav]

Decided to write a guide to all the confusing acronyms that are used by Skoda. This info is from their manuals, sales litrature etc, but put into plainer english!

This will cover all Fabia models so several versions of the same thing may be out there due to the time period I am covering (from 2000 when first Fabia was sold).

Some early Fabia MKI in Classic spec have none of these as they didn't get ABS (first rung on the ladder)!

ABS = Anti-lock Braking System

This uses sensors in each wheel hub carrier and a magnetic reluctor ring on the hub to sense the speed of the wheels. If during braking one or more wheels are going slower than the others, indicating that those wheel(s) have slowed their rotational speed (loss of traction/skidding) and could lock, then the brake(s) on those wheel(s) are released until those wheel speeds match the others.

Works on all wheels during braking only, to prevent wheel(s) locking and skidding. This is "ON" all the time and cannot be deactivated or switched off, unless the main fuse is pulled. The warning lamp on the dash will flicker on and off when the system has been activated, and you will feel a "pulsing" (quite sudden and heavy) through the brake pedal, as if it is trying to push back into your foot. If the warning lamp is permenatly illuminated, this indicateds a problem/fault with the ABS system, and that the ABS system is now deactivated to protect itself. In this case braking is "Old School" without ABS!

MSR = Mechanical (or Motor) Slip Regulation

This uses the engine's ECU to reduce the torque supplied to the drive wheels to reduce wheel spin, eg it reduces the power output (via the ignition timing/sparks/fuel, etc) of the engine to prevent further wheel spin, mainly when changing down gears on a smooth or slippery surfce. It has also been reported that whilst under full power (from standstill) coming out of a junction it has suddenly cut power to reduce wheel slippage, thus leaving you halfway across the junction now under reduced power! This function can not be deactivated or switched off, nor does it flicker any lights on the dash when it has been activated!

EDL = Electronic Differential Lock

This requires the car to have ABS to operate.

This will use the ABS sensors on the main drive axle (front) to sense if one of the drive wheels is rotating faster than the other. It will then brake that drive wheel until both the drive wheels are at the same speed. This works then the accelerator is being used and the brakes are not. Effectively this works as an LSD and is also known as "Fiddle Brakes" and has been used in F1, with manual versions used in tractors, hill climb racing, and 4x4 trail racing. This is always "ON" and cannot be deactivated unless the main fuse for the ABS unit is pulled. When this is working "Active" there is no light that flashes/flickers etc to tell you it is working!

ASR = Anti Slip Regulation

This requires the car to have EDL, MSR, & ABS to operate. This feature gives you a nice button on the dash with ASR (TCS on other VAG cars) on it and maybe a "skid" symbol.

This will use the ABS sensors to sense if the driven wheels (front on FWD) are rotating faster than the non-driven rear wheels . It will then brake the drive wheels (this system only brakes the drive wheels) until both the drive wheels are at the same speed as the rear non driven wheels. It can also use the MSR function to help reduce the power to the drive wheels if needed. This works then the accelerator is being used and the brakes are not. There will be a switch on the dash to deactivate this. The system is "ON" all the time. Pressing the switch deactivates the function and illuminates the respective warning lamp on the dash. If the ignition is then switched "OFF" and then back "ON", the ASR resets to default "ON" again! When this is working "Active" the warning lamp on the dash flashes on and off, indicating that it is currently sorting out the lack of traction!!

ESP = Electronic Stability Program (In this case NOT Extra Sensory Perception.. )

This requires the car to have ASR (EDL, MSR & ABS) to operate. This feature gives you a nice button on the dash with ESP on it and maybe a "skid" symbol. This superceds/replaces the ASR (or TSC) button (you do not get both buttons)!

This system uses a gyro sensor (lateral acceleration and yaw) fitted either under one of the front seats or behind the lower central dash (usually on the exhaust tunnel) to sense cornering, g-force, etc, etc,. It will also use information from the ABS system, power steering wheel sensor, engine ECU, etc to work out what the car is doing and the current inputs by the driver. It then compares these actual readings against predetermined values and then according to the situation it will either brake individual wheel(s)(this system works on all 4 wheels), and/or reduce engine output. All to reduce the amount of under or over steer and keep the car on the course steered by the driver! The system is "ON" all the time. Pressing the switch deactivates the function and illuminates the respective warning lamp on the dash. If the ignition is then switched "OFF" and then back "ON", the ESP resets to default "ON" again! When this is working "Active" the warning lamp on the dash flashes on and off, indicating that it is currently sorting out the lack of traction ans stability!!

HBA = Hydraulic Brake Assist

This increses the optimal build up of brake power, thus making sure that the whole of the braking system potential is used up to shorten the braking distance.

MBA = Mechanical Brake Assist

This requires the car to have a dual rate brake servo.

This muliplies the effort that you exert on the brake pedal to in turn put more force on the brakefluid to help stop the car quicker in an emergency situation. This is allways "ON" and cannot be deactivated.

TPM = Tyre Pressure Monitor

There are two versions made in the VAG group. At the time of writing most VAG cars have the "Indirect" system, only top end models have the "Direct" versions.

"Direct" = This uses battery (or battery less self powered) sensors built into the inside of valves on each wheel to relay the pressure signal to a receiver (either a single central one or one in each wheel arch). This system will tell you the actual pressures of the tyres and will warn of a flat tyre, all using the Maxi-dot display on the dash.

"Indirect" = This requires the use of the cars ABS sensors to measure the roational speed. If a tyre deflates is diameter will reduce, thus the rotational speed will increase! This then idicates that the tyre is deflated! This system cannot tell you the actual tyre pressures, but will iluminate a warning lamp on the dash, or the maxi-dot display, when it detects a flat tyre.

Additional acronyms from 2011 onwards:

DRVBB = Dual Rate Vacuum Brake Boosters

This requires the car to have a dual rate brake servo & ABS, as it is part of it (you get this as standard with ABS)

This is a newer version of MBA.

EBC = Electronic Brake Control

This requires the car to have ABS, as it is part of it (you get this as standard with ABS)

This is the newer version of the earlier MSR system and still uses the engines ECU to regulate the amount of torque transmitted to the drive wheels.

HHC = Hill Hold Control

This requires the car to have ABS & ESP to operate.

This uses the ESP gyros' to sense that the car is on a slope, it then uses the cars ABS sensors to lock the brakes and stop "roll back" (accidental reversing) when moving off from a standstill on a slope.

ABS + (Plus) = ABS including TPM

ESP + (Plus) = ESP including HHC & TPM

XDS = "Cross" Differential System

This requires the car to have ABS & ESP to operate.

This is a more sophisticated version of the EDL system which is linked to a more sophisticated version of the ESP system. This mainly gives better grip in corners by proving more pressure on the inside wheel to prevent wheel spin, and reduce understeer. This will make the car more agile & precise with better traction out of bends! This cannot be deactivated unless the main ABS/ESP fuse is removed!

Fabia, MKI spec combination list

1. Nothing, not even ABS! Only on early pre face lift Classic models in certain engines.

2. ABS

3. ABS & ASR (ASR includes EDL & MSR)

4. ABS & ESP (ESP includes ASR, EDL & MSR). ESP was a factory fit option on vRS version only!

Fabia, MKII spec combination list up to 2011

1. ABS

2. ABS & TPM

3. ABS & ASR (ASR includes EDL, MSR, & MBA)

4. ABS & ASR & TPM

5. ABS & ESP (ESP includes ASR, EDL, MSR & MBA)

6. ABS & ESP & TPM

Fabia, MKII spec combination list from 2011

1. ABS (ABS includes EBC & DRVBB)

2. ABS Plus (Plus includes TPM)

3. ABS & ESP (ESP includes ASR, EDL & HBA)

4. ABS & ESP & TPM

5. ABS & ESP Plus (Plus includes TPM & HHC)

6. ABS & ESP Plus & XDS. vRS version only!

EDIT this is a work in progress and stuff is being added as and when I get the time!!!!

[Jonny5ive]

AFAIK

ESP = Electronic Stability Program

HTH BTW

Edited 30 September, 2011 by Jonny5ive

[inkbm]

Thanks for the info.

Edited 20 November, 2011 by inkbm

[xman]

ASR does not require EDL.

[fabdavrav]

ASR does not require EDL.

I've not seen a Skoda Fabia piece of info that says otherwise for the Fabia!...Unless you know of one??? :wonder:

EDIT

I've just double checked all the Skoda info that I have and I stand by my first post...the info is correct for Skoda Fabia! What you state may be correct for another VAG car, but as I state at the top of my post "this is for Skoda Fabia"

Please provide proof of your claim!

[crazybeeliuzhe]

If my car has ABS already. Does it mean i can activate ASR or ESP through software like vcds? since the latter two are dependent on ABS

[fabdavrav]

If my car has ABS already. Does it mean i can activate ASR or ESP through software like vcds? since the latter two are dependent on ABS

 

 ESP no.....requires different ABS unit.......................ASR might be able, would also require dash button & wiring..........but your engine ecu might not support................

[crazybeeliuzhe]

thank

 

 ESP no.....requires different ABS unit.......................ASR might be able, would also require dash button & wiring..........but your engine ecu might not support................

Thanks. sounds like a big project for me. I think i will stick with my lovely MK1 for a while

[Phil866]

Really helpful stuff. Thanks!