I noticed that front right side brake disk is rusted in my Honda Civic 2018 (indicating the brake has not applied on that wheel), and went to a mechanic for a check.

The mechanic noticed that no brake oil pressure coming to that wheel. After taking off the brake oil tube from the caliper, the brake oil dripped instead of shooting out when brake paddle was depressed. Then he took off the line coming out from the ABS modulator and noticed that no oil pressure in that line at the modulator output as well. Oil pressure was OK in other lines going to other wheels.

Due to this, mechanic said that there is an issue in the ABS modulator and has to be replaced. Since a replacement unit was not available at that time, I got the car re assembled and drove home. The brake paddle felt a bit loose and easily goes down with the slight pressure from the foot, because the mechanic couldn't bleed the air out properly due to the ABS issue as the mechanic mentioned. The next day after a short drive, I noticed that the brake disk has heated a lot in a rear wheel, due to a brake lockup.

There is no ABS warning light in the dashboard. But I didn't scan it for any fault codes though.

Is this caused by a faulty ABS modulator, as the mechanic diagnosed?

If the ABS modulator is replaced, is it required to be re-programmed?

Thanks in advance

  • From your description it sounds as though the modulator sure could be at issue, especially if one side is working and the other not. You might try getting it on a dirt or gravel road and forcing the anti-lock to engage by jamming on the brake pedal at speed. This may do one of two things: 1) get the internals of the modulator to function correctly on the bad side; 2) cause it to not work and make it flash a code, which could help you diagnose. You'd need to be careful when doing so, but might be worth it in the long run. Commented Aug 29, 2023 at 16:56
  • Hadn’t you noticed the vehicle pulling hard to one side when you pressed the brake? I am surprised that you were able to control the car with one front brake not working.
    – HandyHowie
    Commented Aug 29, 2023 at 18:16
  • Is this mechanic trustworthy? Was brake fluid ever flushed and replaced after brake rotors and pads were replaced? What color is brake fluid? Dark fluid suggests it was never flushed out to be replaced with fresh fluid. Abs errors are generally not decoded with generic readers unless specified and your only clue to abs faults/errors is the abs indicator. Even if brake fluid was never replaced, the abs module doesn't cycle brake fluid until an abs event occurs where you feel the strong foot massage from the brake pedal in panic or emergency stops when abs takes over braking.
    – F Dryer
    Commented Aug 29, 2023 at 23:31
  • @Pᴀᴜʟsᴛᴇʀ2 Thank you for the tip
    – Softcode
    Commented Aug 30, 2023 at 1:15
  • @HandyHowie I didn't notice any difference, except few weeks ago I thought the brake paddle is a bit too stiff, but I thought its just in my mind. I usually don't have to apply brakes a lot in my commute, which could be the reason I didn't feel a pull to a side.
    – Softcode
    Commented Aug 30, 2023 at 1:21

1 Answer 1


The issue was with ABS modulator. Replaced it and issue is fixed.

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