The brakes on my van work fine other than the anti-lock the ABS light stays on all the time is there a way of retrieving trouble codes for the anti-lock system if not how do I go about diagnosing the anti-lock system what are the most likely causes of this I am going to be moving to california soon so I want to get this van in perfect working order as I plan on driving it there and keeping it
You'll need to visit a mechanic with a scanner that can access the ABS Computer to have the codes read. The code readers used at auto parts stores normally only access the Engine Computer. Probably the most common cause of a problem is a defective wheel speed sensor. It's important to understand though that fault codes never say to replace parts. They only indicate the circuit or system that needs further diagnosis. The part referenced in the code is only defective about 50 percent of the time.
You should also understand that when you wait a long time to have the ABS system fixed, a second, totally unrelated problem can develop and not set a code as long as the first code is in memory. That second code may not show up until after the first problem is diagnosed and fixed. That causes a lot of frustration among mechanics who have to start troubleshooting all over and tell you more parts are needed, and among owners who are sure their mechanic didn't diagnose it correctly the first time.
February, 6, 2013 AT 1:29 AM
Ok another question is will the tires being bigger than stock cause a problem with the anti-lock system if all four are the same size
February, 6, 2013 AT 1:51 AM
Nope. All that is important is all four wheels rotate at the same speed when going straight ahead. A cracked tone ring can set code and turn on the warning light but that will take from a few yards to a mile or more to occur. The crack is detected as an extra pulse per each wheel revolution and makes it look like that wheel is turning faster than the others.
February, 6, 2013 AT 1:58 AM
What about a dirty I mean like oily dirt caked tone ring or the gap between the sensor and tone ring or dirty tip of the sensor
February, 6, 2013 AT 2:04 AM
And would bigger tires affect the speedometer accuracy or cause it to be jittery
February, 6, 2013 AT 6:04 AM
The only oil or grease that would get on a tone ring would be from the outer cv joint if the boot was ripped. Dirt isn't normally a problem because the sensor's magnetic field goes through that. Sometimes rust can build up on the tip of the sensor and that can interfere with its ability to generate a signal.
Larger tires will make the van go further with each revolution so the speedometer will read lower than your actual speed. On Chrysler products the "pinion factor" is set with a scanner to match tire size and axle gear ratio. I don't know if Fords are the same way. On older vehicles we changed the gear at the end of the speedometer cable to one with a different number of teeth.
You have to be more specific with "jittery". Do you mean how the engine is running? Shaking in the steering wheel? Where do you feel it and what do you feel?
Changing tire size affects a secondary alignment angle called "scrub radius". You won't notice that with tires that are just one size larger but when people start putting big mud tires on raised-up trucks, or when kids put low profile tires on lowered cars, scrub radius changes a lot and will adversely affect braking performance and handling. Scrub radius is not an adjustable angle. It is designed in as part of the steering and suspension geometry and helps all of the parts work together. Lawyers and insurance investigators love to find modifications that affect handling and braking. They will convince a jury that you were partly at fault for the crash when the other guy ran the red light because you were less able to avoid it, and they will be right. That's why in my classes at a community college, we never allowed anyone to modify the ride height or any part of their vehicles that affected the way it was designed.
February, 6, 2013 AT 2:35 PM
The jittery is the speedometer needle it starts bouncing back and forth about 10-15 mph on the and the tires I believe are 2 sizes bigger than stock
February, 6, 2013 AT 5:36 PM
Ok on my abs I found an article about checking wheel speed sensors for resistance and it says that there should be between 450-2200 ohms I checked all four and the results are as follows
left front no reading
right front 2.14 kohm
left rear 2.63 kohm
right rear 2.69 kohm
i tested these with a 10 megaohm digital multimeter my question is are the readings ok on the 2 rears or should they be replaced along with the left front
February, 6, 2013 AT 7:36 PM
Have the fault codes read. The computer will tell you what it is unhappy with. It would appear the left front is open. I'd measure it right from its connector to verify that, and check those terminals.
Check if your van uses a speedometer cable. My '88 Grand Caravan uses a cable and the speedometer bounces once in a while when it's really cold. My '89 Grand Voyager does not have a cable. The speedometer uses the speed sensor signal and can be expected to develop more problems in its lifetime.
February, 6, 2013 AT 9:41 PM
Those readings are from at the connector and the speedometer needle always bounces at around 50 to 70 mph in any weather