ABS Sensor Diagnostics, Troubleshooting and Repair

[mod3lstud]

i had same situation, but in 2001 cavalier z24.is it same procedure?

[markjhicks]

@mod3lstud Procedure is the same for most every vehicle with a few exceptions like a Nissan for example. But the pin-out to the computer is different for every vehicle.

Mark Hicks

Wells Vehicle Electronics

[jasonlongor1]

Checked ac volts to wheel while driving.None shown.Put old one back on everything fixed.Order replacement.Thank you so much for your knowledge and time!!

[markjhicks]

@jasonlongor1 You are very welcome. I am happy you diagnosed it! You an opinion in the future, you have my number.

Mark Hicks

Wells Vehicle Electronics

[jasonlongor1]

Sorry.I did get about 14.4 volts on both sides after a better meter.It's a brand new hub assembly!!:(Could it really be the fault even tho it ohms out ok?

[jasonlongor1]

Ok.No dc volts at either side connecters?Already checked fuses on passenger compartment.

[jasonlongor1]

@markjhicks I was referring to a dc voltage.So drivers side ohms out going down,now check the voltage going up,correct and it should be 9 volts?Thank you again!

[markjhicks]

@jasonlongor1 Correct.

Mark Hicks

Wells Vehicle Electronics

[jasonlongor1]

Haven't checked yet,but that would be dcv in passenger side harness to the the vehicle correct?

[markjhicks]

@jasonlongor1 I am not sure what the DCV is, but I do believe the harness goes up on the drivers side to the controller. Remember you want to be checking the left side (Drivers).

Mark Hicks

Wells Vehicle Electronics

[jasonlongor1]

@markjhicks Here is the thing I replaced both front assemblies for worn bearings.Now the light has come on.Everything ohms out comparable to the old hubs maybe higher.Codes were pulled c1145 C1233.

[markjhicks]

@jasonlongor1

1. At the LF WSS connector, disconnect the sensor from the vehicle harness. Turn the key on and check the voltage between the Yellow/Red (YE/RD) and Yellow/Black (YE/BK) wires of the harness connector. The voltage should show 9 V or more.

2. If the voltage on the harness is correct, inspect the WSS for any damage. Also inspect the tone ring for the sensor looking for any damage.

[markjhicks]

@markjhicks If the tone ring is OK and passing the sensor as the wheels spin, but the sensor will not produce a signal, suspect a faulty wheel speed sensor.

Let me know what you find

Mark Hicks

Wells vehicle Electronics

[jasonlongor1]

Hello and thank you for such an informative video!!I have a 2003ford expedition abs light on.I checked the wires to the hubs and good.Where can I find the harness and what pins should test after I loop the plug back up stream?Any help would be appreciated thank you.

[markjhicks]

@jasonlongor1 If the ABS light came on it means a code has been recorded. Retrieve that code(s) and it will lead us in the right direction. Let me know what it is.

Mark Hicks

Wells Vehicle Electronics

[Tojake14]

Thats Really good work I have the same lights on in my 94 honda accord the check engine light and the ABS light on do you think this will be the same problem???? It will really help

[markjhicks]

@Tojake14 The same procedure you have seen in the video to test the wheel speed sensors, will work on your vehicle too.

Mark Hicks

Wells Vehicle Electronics

[nuwakotthapreak]

Hiyaaaa! Have you thought about - fast abs magic (should be on google have a look)? Ive heard some incredible things about it and my m8 got detailed Six pack abs and lost crazy amounts of weight with it.

[tita0980]

Hi! Have you heard the talk about - fast abs magic (do a search on google)? Ive heard some great things about it and my mate got beautiful Six pack abs and lost tons of weight with it.

[markjhicks]

@tita0980 May I suggest, the next time you watch the video if you are really looking for ABS magic!

Mark Hicks

Wells Vehicle Electronics

[jock150]

Really good video! my dealer garage quoted me £1500 for a new abs pump ($2300) i then did this test bought a new sensor for £40 and it now works perfect.

You just saved me £1450

Amazing, but it makes you wonder how many people who go to dealer garages get the big job bill.....................

[markjhicks]

@jock150 Thank you for the kind words, I am happy we could help you out.

Mark Hicks

Wells Vehicle Electronics

[nyjp005]

I have a 2003 ford explorer sport trac and change the front disk. When driving i depress my brake pedal which would hold high for the moment the go further down in about a second with a hiss sound. my ABS light came on, i check the power steering fluit and it was good. what could be the problem?

[markjhicks]

@nyjp005 If it is hissing when you step on the brake pedal, it usually means you have a leak in the brake system. Look by the master cylinder and calipers / hoses first for signs of brake fluid. Have someone step on the brake pedal and listen under the hood and by the wheels for the hissing sound. Keep the master full of brake fluid.

Mark Hicks

Wells Vehicle Electronics

[003Mexicano]

can anybody please help me. i recently connected my car to a airbag/abs scanner, and it gave me a abs code, the code was about the abs getting overvoltage, what does that mean, how can i fix it. please help thank you

[markjhicks]

@003Mexicano What is the year, make, model, engine size and the code number?

Mark Hicks

Wells Vehicle Electronics

[003Mexicano]

@markjhicks its a 2000 chrysler lhs, 3.5L i cant remember the code but all it said was, overvoltage, the abs light doesnt light up, but the bulb is not burned out.

[markjhicks]

@003Mexicano There are several different codes for over voltage. It sure would help if you could get the code.

Mark Hicks

Wells Vehicle Electronics

[003Mexicano]

@markjhicks ok ill see if i can get the code again, thank you for your response

[jiujitsukiller9]

i learned more from this video than at the twenty seven thousand dollar tech. school i attend. thanx for the video !!!!!!!!!!!!!!!

[markjhicks]

@jiujitsukiller9 Wow What a complement! Thank you very much it is our pleasure to help you.

Mark Hicks

Wells Vehicle Electronics

[spelunkerd]

That coathanger trick is nifty.

[markjhicks]

@spelunkerd The best part is it really works. Thanks!

Mark Hicks

Wells Vehicle Electronics

[w3mq]

this gives me some understanding about the abs brake system before this video I didnt have a clue.Thanks!

[markjhicks]

@w3mq Thank you for the kind words. It is comments like yours that keep us going.

Take Care,

Mark Hicks

Wells Vehicle Electronics

[Biggscastro123]

Where can i go so i can check which sensor needs to be replaced?

[markjhicks]

@Biggscastro123 The easiest place is the ABS controller.

Mark Hicks

Wells Vehicle Electronics

[Biggscastro123]

I have a 2000 bmw 328ci and both my brake pad light and my dsc light are always on. I think it means that my dsc is off but my dsc button does not work. Can changing my wheel speed sensors help?

[markjhicks]

@Biggscastro123 Yes a failed ABS sensor could cause both lights to come "on". the first thing I would do is retrieve the codes for a starting point of the diagnostics.

Mark Hicks

Wells Vehicle Electronics

[eljuarense]

how do you clean and what to use to clean the sensors from dust.i just waxed my car and i used a porter cable,and after i was done i got this from iside the car,(traction control off

stability control off

service ABS system

service traction control

service stability control

service variable effort steering)

now the steering is a little harder.any ideas. thank you

[markjhicks]

@eljuarense I have always used brake clean. When you say you used a porter cable, a porter cable what? Power washer? If you power washed the engine it sounds like you have either gotten some cleaner where it does not belong or you accidentally disconnected a harness. try letting it dry out and then check it.

Mark Hicks

Wells vehicle Electronics

[eljuarense]

how do you clean and what to use to clean the sensors from dust.i just waxed my car and i used a porter cable,and after i was done i got this from iside the car,(traction control off

stability control off

service ABS system

service traction control

service stability control

service variable effort steering)

now the steering is a little harder.any ideas thank you

[101u]

My ABS light is on , Can you please let me know where I can locate the ABS sensors for a 2005 Mazda 3 sedan....mny thx.

[markjhicks]

@101u Have the abs code retrieved and let me know what it is. The sensors are by the wheels.

Mark Hicks

Wells Vehicle Electronics

[101u]

@markjhicks how do i do that without a meter!! thx agin

[markjhicks]

@101u At a minimum you must have an ABS code puller to get the codes out. I believe if you go to AutoZone they will do that for you.

Mark Hicks

Wells vehicle Electronics

[ffas23]

Did everything you mention except rotate the Front wheels to the back which I do every 5,000 miles or so. No missing teeth and everything clean in the area. The gap is real close on both sides as there isn't any way to adjust the gap unless someone was to make up some kind of shim. The new sensors were put in just like the factory ones after cleaning the area. I will try this week to get my friend to bring his Snap-On Scanner home again and attach it to the 2000 Intrepid to chk readings.

[markjhicks]

@ffas23 A Haaaa, I was under the assumption you were taping into the connections at the controller. If you are looking through the eyes of the scan tool, you must also consider the controller, PCM and connecting interface between them.

Mark Hicks

Wells Vehicle Electronics

[ffas23]

I replace both Front  ABS Sensors on the 2000 Dodge Intrepid yesterday. Took the Intrepid for a ride and still have the same problem that I had before with the pulsation in the brake pedal with grinding noise. Didn't take long to do it as I was only 2 blocks from home. What do you suggest now as you have all of my info of everything I have done so far to check this problem out. Had to pull the fuse once again for the ABS Pump in order to drive without ABS. Brakes work great when this is done.

[markjhicks]

@ffas23 Well it sounds like you have an interesting one. Seeing the front sensors were not reading in sync prior, I would recheck them again at the controller to see what we have now. If the same results occur, try rotating the tires front to rear and recheck. If that does nothing, you will need to look at the trigger wheels on both sides of the front. Make sure there is no rust build up, missing teeth and the air gap between the sensor and trigger wheel. This must be very close on both sides.

[markjhicks]

@markjhicks Also check the connection to the controller from these two sensors. use some electronic cleaner on both the connector and controller pins.

Please let me know what you find either way.

Mark Hicks

Wells Vehicle Electronics

[MegaBIGPOND]

hi mark i have 2006 holdenviva the abs light on but when i turn it off the abs light is not there  but sometime came back my friend scan and he say my 2 front sensor is back ?what can i do like clean or get 2 new ones ? thank you

[markjhicks]

@MegaBIGPOND It is hard to say without all the information. Can you tell what codes were set? Also the year, make, model and engine size. I will look it up for you to see what is the most common problem for your vehicle and the test procedure.

Mark Hicks

Wells Vehicle Electronics

[ffas23]

Mark thanks for the pinout diagram. Checked the wiring from all 4 ABS Sensors to the controller and it is good. Once again had a mechanic connect his Snap-On Scanner to the 2000 Intrepid and we drove for 5 miles. He watched each wheel readings from all 4 ABS Sensors. The Rear Sensors stayed about equal throughout the ride. The left Front Sensor was off anywhere from 5 to 8 points depending on how fast I was driving compared to the Right Front Sensor. The mechanic thinks the left Front is bad.

[markjhicks]

@ffas23 Yep, resistance is good, but the output is low. When you slow for a turn or stop the ABS controller thinks the left frt wheel is skidding because the signal stops and pulses the right frt. Happy you found it. If you ever need assistance please let me know, I will do my best to help.

Mark Hicks

Wells Vehicle Electronics

[ffas23]

Mark,Thanks for such a quick response. After seeing your video I was about to do what you suggested in the next couple of days. Just so that you know I have been in the Auto Parts Business now 34 years. Use to own a Carquest Auto Parts Store, sold it and became a Automotive Wagon Jobber that I still do today. Are their any N.J. WD's where I can pick up Wells ABS Sensors from. Always used and sold the Wells Ignition line when I sold Ignition in the past. Will let you know how I make out. Thanks

[ffas23]

Have a ABS Problem in my 2000 Dodge Intrepid but the ABS Light does not come on while having the pulsating problem that I can feel in the brake pedal at low spd. Its been a intermitant problem otherwise the brakes feel great. Replaced both front pads and rotors about a year ago figuring that might be the problem but of course it did not correct it. The problem I am having has gotten worse. Pulled the Main ABS Pump Fuse under the hood and the problem goes away and brakes are great. Any Thoughts?

[markjhicks]

@ffas23 Usually this problem is caused by a wheel speed sensor that stops generating a voltage at low speeds. Start on the front wheels. Jack them up one at a time and connect a voltmeter to either the sensor connector or where it connects to the computer, like we did in the video. Set the meter to AC volts and spin the wheel by hand. Even at slow speeds like this the sensor should generate some voltage. If it does not the sensor needs to be replaced.

Stay in touch,

Mark Hicks

Wells

[ffas23]

@markjhicks, On my 2000 Dodge Intrepid I did what you suggested to do and hooked my Digital Multi-Meter to both ABS Speed Sensors one at a time in front of the car and then the other 2 in the rear directly to the Sensors in the Volt position. Each Sensor gave me a reading showing me they are working when spinning the wheels by hand as fast as I could. Also did a Ohms test and also got readings there. What do you suggest I do from here? Car is up on my lift. No need to use it until fixed.

[markjhicks]

@ffas23 If the ABS is activating at low speeds it is because the ABS controller thinks a wheel has stopped turning. Try turning the wheels at a slow speed to see if you are generating AC voltage. That is the key, you must be looking for AC voltage. Make sure they are all generating at a slow speed. You might also want to check for the same voltage at the controller to make sure the wiring is in tact. If you need a pin out for the controller, send me a message from my channel.

Mark Hicks

Wells VE

[ffas23]

@markjhicks,As mentioned I spun all 4 wheels with the Multi-Testor attached to each sensor. I have readings in the Volt Scale and Ohms Scale. Volts Scale on the Passenger Front wheel with hand spinning was from 0 to1.1, Driver Side Front 0 to .07, Pass Side rear from 0 to .04 and Driver Rear from 0 to .02. On the Ohm Scale without doing any spinning the Pass Front read 1.10,Driver Front 1.09, Pass Rear 1.09, Driver Rear 1.12. Reading were directly to the sensor. Do need a pin out for control

[focijohn]

@ffas23

Here in the UK I've seen a few ABS pick up rings split (trigger wheel as shown at 4:32). This usually gives a symptom of the ABS kicking in intermittently at low speeds and doesn't always throw the light on. If you can see the trigger wheel it might be worth seeing if you can see any splits or bits missing.

[ffas23]

@focijohn, I already checked that out and no bits or teeth missing on the Dodge Intrepid on either side in the front where I believe the problem is coming from. Getting ready to check everything once again today and will visually check everything plus use a multi meter on each sensor starting at the front as suggested by Mark. Will let everyone know how I make out here. Mark if you are reading this I wrote back to you asking if you knew of any WD's here in N.J. selling Wells Sensors?

[madnis007]

I have a 2002 Camaro V6. My ABS INOP and brake light come one and stay constant whenever I drive over 40 mph. However if I am below this speed the ABS or brake light does not come on. I am thinking it may be a ABS wheel speed sensor problem. Just wanted to see what you thought. Thanks.

[markjhicks]

@madnis007 I think you are probably correct. I suggest getting the ABS code pulled, it might lead you to the correct sensor. Whenever the ABS light comes "on" a code is stored in the memory. I hope this helps, if you need any further information just let me know.

Mark Hicks

Wells vehicle Electronics

[techdavey1000]

I think that there are different types of sensor. The old ones have a magnetic probe and presumably a coil, they are tone generators. Sometimes the tone wheels split owing to rust getting underneath and the extra wide tooth gap will put the light on. Don't get suckered for a whole new drive shaft, instead clean up the broken ring and Sifbronze weld the crack. It does not matter if bronze fills the gap between the teeth as it is non magnetic. Refit with Loctite, & paint it! Light now out Voila!

[markjhicks]

@techdavey1000 You are correct in thinking there are different types of sensors. The tone generators as you call them are magnetic reluctant. They generate an AC voltage that is sent to the ABS controller or PCM to determine wheel speed. The exciter wheel or bearings can emit rusty metal that will inhibit the generation of AC voltage. However, this was not the problem with this vehicle. When the resistance reads very high like this one did the sensor needs to be replaced.

Mark

[markjhicks]

@h23sirlude I had better watch my Ps and Os, I mean Qs, with you around :). Take care my friend and I hope you have a wonderful New Year.

Thank you,

Mark Hicks

[jimmyhorse1]

I have a 2004 Honda Accord LX (2.4L, front disc, rear drums) I had the ABS pump replaced 1 year ago. The ABS system was fine until recently. My mechanic recently told me that one of the sensors was seized into the hub and he had to replace the hub and sensor. After that was replaced, I'm still getting the kick back in the brake pedal, on occasion, when i'm turning/slowing (however, ABS light is off). Mechanic now says the speed sensor is not calibrated. Does this make sense? Help appreciated

[markjhicks]

@jimmyhorse1 I don't see any calibrating procedure for these wheel speed sensors. Here is the diagnostic procedure from Identifix :

1. The wheel speed sensor is a transistor so checking the resistance is not a good test. First backprobe the Green/Black wire with a volt meter and turn on the key. The ABS control unit should send out 10-12 volts to the wheel speed sensor.

[markjhicks]

@jimmyhorse1 1. If there is no voltage or the voltage goes away after a few seconds then the control detects a problem with the sensor or the circuit.

2. Verify the Green/Black wire and the Pink wire is not open or shorted. If the harness is OK, then suspect a faulty wheel speed sensor.

[markjhicks]

@jimmyhorse1 If there is voltage on the Green/Black wire, then backprobe the Pink wire and turn the wheel there should be a pulsing voltage signal produced by the wheel speed sensor back to the ABS control unit if the sensor is working correctly.

3. If there is no signal and the correct wheel bearing is installed with the magnetic side towards the wheel speed sensor,

[markjhicks]

@jimmyhorse1 and the wheel speed sensor has a good ground threw it mounting, then the wheel speed sensor is faulty and will need to be replaced.

[shanewalker25]

i have a 2001 chevy blazer 4x4 4.3 engine. i have abs and brake light lit at all times on my dash. so i scanned it with an abs scanner "actron" and the following codes came up. c0281 stop lamp switch c0265  ebcm motor relay circuit c0251 c0246 c0242 c0252 c0245 c0241 whichall 6 codes say ebcm control valve circuit c0226 left front wheel speed signal missing and c0222 right front wheel speed signal missing. and my brakes go all the way to the floor very mushy please help!

[markjhicks]

@shanewalker25 You have so many codes ,,,where do you begin? I suggest clearing the codes and then as soon as the light comes "on" pulling them again. This will give us primary code(s) and we will have a starting point.

Mark Hicks

Wells Manufacturing L.P.

[techdavey1000]

@shanewalker25 Hi Shane, I had a weird spongy brake fault on a Ford Granada 3.0L V6. Next I started to get bad tyre wear so I paid the garage to check the wheel alignment. They took my money and said everything was OK. Before long all my spare wheels were used up and had wire showing so I had to buy a new tyre. The last spare wheel was rusty and had stuck to the hub spigot so the fitter had to give it a good hard tug - all was revealed - the wheel bearing was gone! Nu bearing fixed brakes 2!

[shanewalker25]

i have a 2001 chevy blazer 4x4 4.3 engine. i have abs and brake light lit at all times on my dash. so i scanned it with an abs scanner "actron" and the following codes came up. c0281 stop lamp switch c0265 ebcm motor relay circuit c0251 c0246 c0242 c0252 c0245 c0241 whichall 6 codes say ebcm control valve circuit c0226 left front wheel speed signal missing and c0222 right front wheel speed signal missing. and my brakes go all the way to the floor very mushy please help!

[dogsknobs]

my abs is clicking with normal braking. whats wrong?

[markjhicks]

@dogsknobs By clicking do you mean the ABS is activating at low speeds? If so, typically it is a wheel speed sensor that is not generating at low speeds. You can check it like we did in this video. If you reply please mention the year, make, model and engine size. Also you should check for ABS codes and if you have any, what are they. The more information you offer the more I can help.

Mark Hicks

Wells Manufacturing L.P.

Mark Hicks

[markjhicks]

@Dogapsa Get the code it is storing and let me know what it is.

Mark

[markjhicks]

@Dogapsa That's great, I am happy you have it going again. Take Care,

Mark

[markjhicks]

@Dogapsa let me know what happens please,

Mark

[markjhicks]

@Dogapsa From information you have given me, it appears either the system has air in it and needs to be re-bleed or possible power bleed, or you have a leak somewhere that you are not seeing or the master or somehow you are getting air back into the system after you bleed it. Think about it for the pedal to slam to the floor with no resistive pressure means air in the hydraulics. I would try bleeding again, start with the Right rear go to the left rear then the right front finish left.

Mark

[markjhicks]

@Dogapsa At this point I will have to agree with your tech. If something where stuck like a caliper, the pedal would not go to the floor. It would be hard and not travel as far. One quick way to check if the master is doing anything. Have someone push the brake pedal like they are bleeding the system, then crack one of the lines connecting to the master. You should see a stream of brake fluid come out. Question did you bench bleed the master before installing it?

Mark

[markjhicks]

@Dogapsa Before you go any further if the brake pedal is just sinking to the floor, you have to be absolutely positive there are no leaks anywhere! Is the master cylinder staying full?

Mark

[arg13415]

back charge the O2 sensor repair work to the shop that did the clutch work.

[markjhicks]

@arg13415 It was a couple years ago when the clutch was replaced. We discussed it and the owner of the vehicle opted not to pursue that.

Mark Hicks

Wells Manufacturing

[foxdmulder]

Im considering buying a modis, I see you use one, would you reccomend one as some people say because its snap on its over rated, any feed back would be appreciated

[markjhicks]

@foxdmulder A modis is nice but slow to start and it has battery issues. Two things it does well are multi traces and PID graphing. If you are an experianced scope used it is a good choice, If you have not been using a scope I suggest purchasing a used dual trace and then move to a more complicated scope. But before you buy a good scope also check out ATS test solutions, this will be the scope we use in our upcoming scope training videos.

Mark Hicks

Wells Manufacturing L.P.

[foxdmulder]

@markjhicks Many thanks for your valued insight, Looking forward to your scope videos as I am new to this process.

[markjhicks]

@foxdmulder you are very welcome,,,it will take a bit for the lab scope videos but it will be worth it. The first one will be out in about a month, it will be on why a lab scope is important to have and understand.

Mark Hicks

Wells Manufacturing L.P.

[therockkkkher]

sorry but isnt the hub supposed to be filled with grease and does grease have any effect on the sensor?

[markjhicks]

@therockkkkher This hub does not have grease in it. However some manufacturers do have grease in the hub. Grease will not effect the sensor operation. However, anything metallic and or magnetic will, such as metal chips or shavings. Great question, if you have any further thoughts please let me know.

Mark Hicks

Wells Manufacturing

[hawaiismainlander]

do you know how to do it on silverado chevy 2001?

[markjhicks]

@hawaiismainlander Below is my work phone number. I would be happy to send you the pin out for your vehicle. I will need year, Make, Model, engine size, 4 whl or not, information

1-800-558-9770 press 3

Mark

[4x4PROX]

Thanks alot!

[markjhicks]

@4x4PROX You are welcome, if we can be any further assistance let us know.

Mark Hicks

[markjhicks]

@atoxx1 Thank you for the kind words. The back probes in our videos are from MAC tools. They work great!!

Mark Hicks

[ddbala]

Very very good diagnosis video. I really like this video. Thanks a lot.

[markjhicks]

@ddbala I am happy to hear the video helped you. If you have any questions about your diagnosis I will help you.

Mark Hicks

[CRXED9Bert]

this is a honda civic coupe EM2 1.7 LS or ES(vtec) pre-facelift... not an accord..

[markjhicks]

Bert you are right, it is a Civic. My mistake during the editing. However I hope you were able to gain from the message of the video, there are many very solid lessons contained in it.

Mark

[nobleheight]

Are ABS codes pulled from the ABS module using a separate connector (different than the OBD II DLC)?

Or are the ABS codes pulled from the same DLC and connector as the regular OBD II codes?

[markjhicks]

They are pulled the same way as the Powertrain codes just using a different part of the scan tool.

[JayNav09]

I have a 96 honda accord ex with ABS light on constantly. Would the locations of the connections be the same as the video. I can use your help. Thanks

[markjhicks]

On a 1996 Civic the rear speed sensor are located in the hub. The testing procedure we show in the video will work on your vehicle also. i suggest checking the AC voltage output from each rear wheel before replacement. It will take about one hour per wheel to replace the sensors.