Suzuki 2008 XL7 brake pedal pulsating, no warning lights, while braking

Thank you for reply to help. Got 2 new rear tires matching with front tires 6-14-17 same day vehicle had yearly required pa. State inspection 6-14-17 at same dealership, 70,261miles, nothing found wrong. Pulsating brake pedal started about 3 weeks, 70,501miles, 240miles after State Inspection, 7-12-17. 8-7-17, 70,675 miles since brake pulsating started, 4 weeks, 174 miles, took to small shop to look at it he didn't have scan tool. He couldn't handle it. 8-8-17 made appointment with dealer where I had all inspections done 3 years since I have had car and where original owner bought it new when it was a Suzuki dealership, before filed bankruptcy in US 2012? Appointment 2 weeks out. I took XL7 over to dealer 3 days later to see if someone could test drive it to some idea. The Service Manager agreed to test drive and I asked to ride along. He said right away it is ABS issue with wheel speed sensors first thing he would check then the ABS hydraulic control valve or he may have said the control module, dealer price $523. I wonder if he said modulator valve not sure if same ABS hydraulic control valve? $1071. dealer price plus labor. Today mechanic assigned to repair last 3 days, has day off. 8-18-17. Only 2 hrs last three days able to look at it and wait on Suzuki technical support. Service manager says tomorrow they will check main electrical harness, "buss" line voltage. Check for any bad wires.

Highly recommend test drive with appropriate (professional grade) scan tool connected with ABS module scan selected .. Live sensor data will show ALL wheel speed sensor readings so any deviation can easily be noted .. Furthermore the rest of the system can be checked with same scanner .. Hopefully the personnel diagnosing the problem is fully aware of this.. Hope you have good luck with it!

The following post I pasted from a thread on another Web site dealing with activation of ABS when road conditions are not hazardous to require the passive engaging of ABS. "It could also be a defective strut or shock absorber. I am having the exact same issue myself presently. When a strut is empty of fluid and gas there is no dampening effect and you are bouncing on your springs. This effect is also noticed when braking at low speeds as well as when turning. When braking with dead struts your tires have intermittent contact with road and your ABS tries to compensate. I will having the front struts changed in a few hours time and will get back to you and tell you if the problem is remedied. Update: Good news, Struts are changed and it appears that that issue I had finally solved. Now my problem is relearning how to drive without having to constantly compensate and bouncing all over hell's half acre. :) share improve this answer answeredJul 18 '16 at 5:22 resident_heretic 2,823●1●5●17 editedJul 18 '16 at 15:36     Glad you figured out your problem. I noticed that the ABS most likely is to kick in when I drive into my driveway (uneven surface with steering wheel turned). Do you think it may be possible to see with naked eyes if one wheel does not have enough contact with ground? Any other tips how to prove or disprove your hypothesis on my car? Thanks! – john1234 Jul 20 '16 at 6:25     @John1234: That was the only time that my ABS would kick in unexpectedly was on uneven road surfaces and while turning. On good condition dry roads didn't activate so easily. As for whether or not you could see it naked eyes I don't know but you might notice it by feel in the steering wheel. All I know is that when I changed the struts the problem disappeared. – resident_heretic Jul 20 '16 at 16:40 add a comment up vote2down vote Brake pedal pulsing is most likely ABS engaging. To disable ABS, remove the fuse for it in the fuse box that is under the hood. Do have a shop look at your ABS system if the light has been coming on. Erratic brakes are not something you would want. share improve this answer answeredJul 18 '16 at 3:35 tlhIngan 10k●3●15●45     Thanks! After removing ABS fuse, the pulsing brake pedal issue went away. However, now I have follow-up question -mechanics.stackexchange.com/questions/33114/… – john1234 Jul 20 '16 at 6:09 add a comment up vote1down vote I believe this is due to a warped rotor. The pulsing will be due to raised areas on the rotor pushing back against the brake pads. share improve this answer answeredJul 18 '16 at 3:28 MeltingDog 1,754●4●18●32 2  Warped rotors would make the pedal pulse all the time, not just some of the time. – tlhIngan Jul 18 '16 at 3:30 2  Pulsing pedal because of rotor issues should be easily distinguished from ABS kickback. Shouldn't really affect braking distance nearly as much either.– I have no idea what I'm doing Jul 18 '16 at 9:48     @tlhIngan - Not so. I'm experiencing it right now in my truck where it doesn't pulsate all the time, only under certain load. – Pᴀᴜʟsᴛᴇʀ2♦ Jul 18 '16 at 11:28     @MeltingDog I think in my case "pulsing brake pedal" is indeed due to ABS kickback, because 1) in my case the pulsation is more obvious than here (youtube.com/watch?v=4rfciRq2JzU) and 2) removing ABS fuse has made "pulsing brake pedal" issue go away. Do you think that warped rotor could also make ABS kick in when it is not supposed to (in the answers three root causes have floated - bad sensor, bad struts and possibly bad rotor)? – john1234 Jul 20 '16 at 6:40     @john1234 honestly, I'm probably not the best person to ask as I've never worked on a car with ABS but I do know that the ABS sensor reads off a toothed sensor ring that is separate to the rotor. Unless the damaged rotor has impacted this then I would tentatively say no.buyautoparts.com/images/abs-speed-sensor-image.jpg – MeltingDog Jul 20 '16 at 22:12 add a comment up vote1down vote This has happened to me with a defective ABS sensor (front, passenger). I mistakenly gouged it while changing the wheel bearing which caused it to intermittently give false signals at lower speeds (ABS ring turning slowly = sensor misinterpreting it as stopped?). Typically faulty sensors will throw the ABS warning light, which mine eventually did. share improve this answer answeredJul 18 '16 at 13:18 Andrew L 301●1●5" END of Thread from another Web site. Thanks Steve