ABS and tire light comes on, goes out when re-booted

Well, a serious problem may be pending on my 2002 Sienna here in Mexico. I will be doing some serious investigation before I panic and do anything at all.

I get a lot of flats, and usually lose a tire on average each year, due to lots of junk on the roads and streets. So, in the last couple weeks, sometimes the tire light comes on, and I assume I have another leak. But, then it has gone out again after a while and the pressure is okay.

Yesterday, moderate temperatures, I drove only 3 miles or so, to visit friends. The car sat an hour or more. When I started it, the ABS light was blinking and the tire light was on.

I stopped the car, and re-booted, that is, turned it off, and started it again. Lights were okay.

Today, I started it, and the ABS and tire lights were on, and not blinking. I re-booted the car, and they were okay.

Three things come to mind.

  1. Computer

  2. Bad or intermittent connections somewhere in the light system. The fact a re-boot fixes it tends to preclude this, but with electronics, there is no such thing as 100% sure anything.

  3. Ambient conditions. I normally park at the end of the house, but workers first put a dump truck load of sand there. Then, they moved in a couple pickups of laja (flagstone) with pieces from very small to maybe 150 pounds each piece.

So, I have parked along the house, and there is a roof drain which drains 500 square feet or more, with a 13 foot drop. I park with the driver’s door maybe 3 to five feet from the place it hits. And, it has been raining lightly for the last couple weeks, and heavily the last three days. No water in the car body, but who knows what happens underneath.

I stopped typing and moved enough stones to park there again, and will be telling the workers they need to keep my parking place open for me.

I know we used to have problems with our electronics in private airplanes, and the fix was to install a liner inside the electronics access door. Electronics does not work well when submerged.

I also checked with my new scanner, and no DTC; and no history at all.

No codes at all. I shorted the two pins stated both in the Toyota shop manual, and Hayes, for ABS problems, and it blinks steadily, which Haynes says no failure code found. No DTC history,. no non-continuous failures, though I have not been able to find what they are yet.

I did Google a lot, and found several places which said a dirty wheel sensor can cause pretty much this failure. Well, the water from the roof was not far from either left wheel sensor, so I will look at those sensors when it isn’t raining.

I have had the same problem – for a month or two, the ABS light comes and goes. The DTC connector won’t reveal ABS problems. The system uses a separate controller with its own connector for a special ABS scanner.

Finally, yesterday I went to a friendly good ol’ boy shop for other work and they used the ABS scanner to check my brakes, gratis. The screen said “loss of continuity right rear wheel sensor.” We hoisted the car and the wiring checked out OK.

So we assumed a bad wheel sensor. The mechanic made a call to his supplier and learned they wanted $189.99 for a new sensor! I declined and he checked the internet and eBay and found he could go as low as $131.

Again I declined and went home, back to the internet. I found someone in Wisconsin parting out his car similar to mine. He agreed to sell me the pair of rear wheel sensors for $20 plus shipping. Marvy! And so I wait.

So irlandes, that is my situation. As for you, you’ll likely have to keep driving without a working ABS until you can find someone with the proper scanner to determine your exact malfunction. Unless you can work some sort of cleaning miracle.

Thank you for sharing. All information is useful in its own way. You did not say which car you have.

In the 2002 Sienna shop manual, (Also Haynes says the same thing) it tells how to short two pins on the OBDII connector, Tc and CG, the fourth from the left on the top row, and the fifth from the left on the bottom row.

You then turn the car to operate without starting the car, just as you do for scanning failure codes. Count the times the ABS light blinks, and there are 33 possible failures, plus a blink every half second, which says no ABS failure codes.

Open Circuit - right rear speed sensor or circuit, which sounds like what you are saying, is on my Toyota Sienna, 38, that is, three flashes, pause, 8 flashes.

I mentioned August 31 above that I had run this test, and no ABS failure code found. Looking back, I realize I did not spell this out in sufficient detail. Sorry.

My car, with the above action, shows 2 blinks a second, more or less, continuously, which the book says means NO FAILURE CODE ON ABS.

So, I assume two things until I find differently. My ABS is actually working, and paying someone to scan the ABS will be a total waste of money, since the ABS has already said no failure found. Of course, Murphy may be at work, and the failure codes may not be reporting what is happening. But, at this time, until I learn differently, I am forced to assume the problem is not the ABS, but the ‘reporting’ part of the system. That could be the computer, or interface circuitry. As much as I hate it, I may end up taking it to the dealer.

I do not know if other makes/models have the same “short two pins to read ABS codes” or not. You did not state which make/model/year your car is.

A quick Google showed the same concept for Ford Trucks, down the linked page:


I think the Ford method requires a volt meter to read the pulses, and may be for older Ford trucks. So, this shows at least some other models provide direct, non-scanner reading of ABS failure codes.

I just found a summary page on ABS codes, which has an interesting, and perhaps relevant statement.

“What is more, intermittent problems may not set a fault code. So if there is no code, do not assume everything is fine. You have to check the operation of the system as well as individual components to figure out what is wrong.”


That could be why a URL said sometimes one needs to check wheel sensors. It has been raining here in rural Mexico, so when it clears up a bit, I will look at the wheel sensors, assuming I can identify them from the drawing in the shop manual.

I did not mention my car (Dodge) because I felt this is irrelevant. Manufacturers buy their ABS separately and change them frequently. My car uses the Bendix 9 or 10, and the following year-model switched to the Bendix 4. Other manufacturers are Bosch, ATE, etc. Few owners really know (or care) which system they have.

So my system is completely independent of the car’s OBDII system. Apparently your system is more advanced than mine and allows you to check for codes by shorting pins. I don’t think that works for me, but I am going to check on it.

As for identifying wheel sensors, just look for something bolted into the brake with a wire attached to it. The ABS ought to be the only electrical gizmo for each brake. Check the wiring for electrical integrity.

I did an internet search and found:

“Many newer ABS systems have no flash codes so you must use a scan tool to pull the codes. These include all Bendix systems (Bendix 6, 9, 10, ABX-4 and Mecatronic found primary on Chrysler cars and Jeeps), as well as Delco Powermaster III, Delco VI, ITT Teves Mark 4, and Bosch 5 and 5.3 ABS systems.”

So I can’t pull codes myself. I can’t find who makes your Sienna ABS but apparently you have the ability to obtain blink codes.

Very definitely! Both Haynes and the Toyota shop manual give the same methods and codes. I wonder if there is a way to look at a key component and see what it says. I know nothing about ABS, except what I learned fussing with this problem. Maybe I need to read up and look at the car. Thanks for information.

Weather was good today, but I forgot to look at wheel sensors for crud. So, I added it to my computer alarm system for tomorrow.

Keep at it. My part did not ship yet because of the Labor Day holiday weekend but I will let you know how this plays out.

This may be redundant, but…

There are basically two ways that the tire pressure monitor system works. 1, there is a wireless pressure sensor in each tire (mostly found on expensive high-end cars), or 2, the system uses the same wheel speed sensors used by the ABS system. If one tire is going flat, it will have a smaller diameter than the others, and therefore will rotate faster on a straight road. The ABS system monitors the speed of the 4 wheels and if one is moving faster than the others, it sets the low pressure warning.

First, check the owner’s manual. There may be a procedure to “train” the system when you install new tires or have a tire repaired. You may just need to train your system.

If that is not the answer, then I guess that one or more of the wheel speed sensors is faulty.

StrongDreams is right about the way the system work. He’s also right in that those systems that use the wheel speed sensor will have an “initialization” procedure (Toyota’s term for the protocol). I can also add that the wheel speed sensor based ABS system were Toyota’s system of choice in th eearly 2000’s. However, the need for initialization will have no effect on the ABS light.

I’m going to go with a dirty wheel ring or failing sensor. A repair manual from a psrt store will show you how to clean and, if necessary, replace these parts. This is a DIY job for anyone who’s good with their hands.

Yes, my 2002 Sienna uses the second method of tire pressure, using data from speed sensors to detect a tire which is rotating at a different speed. I think I read it is supposed to detect a two pound difference in pressure. And, experience has shown that to be probably correct.

Once, some knuckleheads here took a tire off with a hammer. Later, driving across Georgia, the tire light came on at 70 mph. I stopped and checked the tire pressure, and they were okay. I drove on to a rest stop, and when I examined that tire, it was coming apart, and had gone out of round, which changed the rotation rate of that wheel. Saved me from a horrid blowout at 70 mph by alerting me to the problem.

To calibrate, turn on ignition, and hold down the button on the dash, left of the steering wheel, until the tire pressure light blinks three times then stops blinking. Just don’t do it until you have those tires at the same pressure, or you have just calibrated them out of whack. Well, I guess you can, because it will still tell you if one changes a lot.

And, it is true the TPMS light has no effect on the ABS system itself.

Because this happened after the car was parked maybe 5 feet from a roof drain during heavy rains, I have also been suspicious of dirt on the wheel sensors.

Possibly contradicting this is the fact that sometimes it works perfectly, but fails as soon as I start the car, with no wheel sensor action, except self-test.

I drove to Puebla yesterday, 58 miles on mountain roads, over 2 hours, and it performed flawlessly, except the tire light, which I am betting was knocked out of calibration by this problem.

Also, I learned the shop manual has a “speed sensor check” enabled by shorting two leads on OBDII connector. When it is in fail mood (mood, not fail mood, because it seems to be moody) and I enable speed sensor check, it enters a continuous fast blink display on the dash. When it is consistently working okay, it will not blink on the dash at all when I enable speed sensor check.

But, turning the key off and on will vary if it works or not, without actually starting the car at all, nor moving it. So, without more data, I cannot rule out a simple ABS computer failure for the speed sensor test loop.

Big family funeral here the last few days. I will be Googling for replacing the speed sensors, since none of the two manuals I have tell anything. The leads are obvious,and there is one bolt, but I need to know if there is a tricky alignment procedure. I don’t want to get one off, and learn it is tricky to reinstall.

But, it they are just dirty, I’d rather clean them myself. A dealer, the folks with the Toyota ABS scanner, are going to replace them at great expense, and not clean them.

Checked Autozone, and though the instructions don’t give much detail, it seems like an easy job. Will look at the front one soon.

Follow-up report: I finally got around to replacing my rear wheel sensor with the used one I got from a fellow who was parting out. Replacement was simple enough. When I went out for a test drive, lo and behold, ABS was working normally. No more warning light. Just thought I’d finish up on this one.

I have been trying to post a follow-up for some time. The POST COMMENT button simply will not work on Firefox in Kubuntu Linux. Usually when I encounter something like that, a programmer has taken the lazy way out and plugged in something from Microsoft to save time. MS uses non-standard programming, in hopes of stiffing the competition. Years ago, I hit that all the time. Now, this is very rare, and also involves not testing the software on a variety of systems. I had to come into Windows Vista to post this. Yuk!

On my brakes, it was the computer itself. Very expensive.

cdaquila, not only that, but also in Linux, I had trouble signing in at all. Only your URL, I hit a lot of pages in a week, with no problems.

Edited to try to spell cdaquila correctly.

Thanks, irlandes. I’ll pass it on. I haven’t heard this from any other Linux users.

It is really strange, I admit.

Oops, this time it worked, but last week it was so bad I didn’t check in all week, and today it did it again. Kubuntu 10.04, Firefox 3.6.23, also Konqueror web browser.

I will check it out. Failed after 7:36 posting, re-started Firefox and it worked.