Why can't you easily bleed brakes with ABS?

I was watching videos on how to bleed brakes and some comments mention that they couldn’t do it because they had ABS on their car and didn’t have a scan tool?

Could someone enlighten me why it’s not easily possible without a apparently expensive scan tool?

Don’t believe everything you read on the internet. No scan tool is needed to bleed brakes because its such a simple procedure.

Some vehicles do require a scan tool to cycle the ABS pump and valves to purge the air from the ABS.

I’ve never had a problem bleeding ABS brakes. Never used a scan tool.

Same here. I think as long as the fluid level in the master cylinder doesn’t get too low, no air will be introduced upstream from the ABS control unit.

Working solo, I have often used saran wrap and a rubber band over the top of the master cylinder, with the cap off. This slows down any tendency for an open brake line to leak.

Another old wives tale that plagues the automotive world. Started by people who know nothing about mechanical or electronic devices.

Some vehicles require a scan tool to properly bleed the brake system.



Does this require a manufacturer specific scan tool or are there generic scan tools that can be used?

Each manufacturer has it’s own ABS system.

So you need a specific scanner or a program key for a generic scanner.


There’s a lot of bad information on the internet. I’ve watched a few that made me cringe.

The truth is that there’s no special magic to bleeding brakes with ABS. Simply attach a clear plastic tube to the caliper’s bleeder, stick the other end in a bottle half full of fresh fluid, and pump until the air in the tube has burped out and keep going until you’re satisfied that the line has been purged. If you want to do the entire system, start with the line farthest from the ABS modulator and work backwards.

ABS only differs from “old fashioned” brakes in that there’s a solenoid-operated valve in the line between the master cylinder and the caliper. If the system senses that one wheel isn’t turning, it assumes it’s slipping and sends a squarewave to the solenoid causing the pressure in the line to pulsate. It’s recommended not to backpressure the modulator, and I don’t, but I know some who do and they’ve never had a problem either.

NOTE: I recommend always using the bleeder when depressing the caliper pistons too. That purges some of the old fluid from each caliper as you do the brake job. Be sure you keep the reservoir full while you do this.

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Here’s another example where a scan tool is required to properly bleed the brake system.


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I had a 2002 Chrysler Town and Country, made when they were owned by Mercedes. The owners manual had large warnings the it had to be towed to a Chrysler dealer if the brakes needed bleeding. I asked my mechanic about it and he said, well we have had a lot of problems bleeding them, let me ask my computer guy, he was supposed to be finding out about this.

The computer guy said, that Mercedes would not release the computer code to anyone but their dealers that you needed to open the valves in the ABS. A couple of years later I asked again and he said, yes, they had been forced to release the codes.

Because of this and the fact the dealer wanted $200 to bleed the brakes, I just used a turkey baster to remove the fluid and refilled it 3 weeks in a row. I will admit I did not actually try bleeding them because I didn’t want to take a chance on disabling the car.

I recently bled the brakes using a one man bleeder kit on my 2012 Camry and it was quick and easy.

Yeah, I watched a tech on Youtube Eric the car guy and he mentions the same. I plan on doing that to.

Hondas do it differently:


And Hondas do it differently than other Hondas, too:

Always check the manual with them.

For my car it’s different to. They say rear left, front right, rear right front left.

Point taken…specifically, mine is for a 2010 Insight or 2006-2007 Civic.

Also, no mention of needing a scan tool to bleed; it’s just like the old days.


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Ok thanks guys. Just wanted to make sure I wouldn’t screw something up by bleeding or just opening the bleeder when pushing the piston back in.

Seems like the common sense diy’er way to proceed is to bleed using the normal procedure, and if that doesn’t work, can’t get a firm pedal, seek out any special instructions or scan tools needed for bleeding the ABS system.

Seems to me you should seek any special instructions and/equipment first, lest you be left with an undrivable vehicle after the usual bleeding procedure leaves you stranded. Just my 2cents.