This is a compilation of my posts from the other board in response to a problem that Tripplec was having. Most all of us with affected year vans will likely see this problem. Feel free to fill in the rest of the post if you guys want. I just thought it should be archived in case the database on the other board goes bye, bye, as it is a serious safety concern. I also added the test and repair procedure and specs as I originally sent a copy of the TSB to Tripplec and didn't have time to get to posting it before the board went down. You may wish to do the repair procedure even if you aren't having problems as a preventive measure.
This affects '95-'03 Astro/Safari
GM has recalled a whole bunch of trucks for this problem. My dad was having problems with his 2000 Silverado 1500. I test drove it for two days, then litterally came within 1 inch of hitting the car in front of me at a gas station, thank god for parking brakes. If you pull the ABS fuse you can safely drive the van, had to do this to his truck until GM officially recalled it, they said there was a recall coming in a couple of weeks, it had started in other regions of the U.S. It was 2 months later. I don't think that they have a recall on the Astro/Safari but give GM customer service a call and raise hell, I bet they fix it for you. If not, I recommend replacing the sensor as the plastic deforms. The hole it is in gets rusty and "puts the squeeze on" the sensor. If it was my vehicle I would replace the whole assembly as you are for sure going to get the hub full of rust and dirt when you clean the mounting hole with a wire brush (use one like you would use for cleaning copper plumbing fittings before soldering).
The system won't set a code because it sees a sensor that is dropping rate and thinks that the wheel is locking up. I know what you mean about the pedal effort when it occurs. I could squat over 400lbs in high school, and while that was a while ago, my legs are still quite big, and there was no way I was stopping that silverado with the service brake. Got out, gassed up and pulled the fuse. It usually starts out very intermittent. Had to drive dads for 2 days before it tried to kill me. Ok so the speed is low when it happens. Since I have seen 3 or 4 more and sent all but one to dealers under warranty. The sensors are held in by one bolt, due to the rust they can be a pain to pull out though. I can see if I can find the revised resistance and voltage specs for the sensors, I don't know if I still have the TSB around and I had to get it from a dealer. I'm going to the dealer tomorrow morning for parts... If I remember right you may be able to spin the wheels while measuring the voltage and the lower voltage one is most likely the culprit, but both may be bad. If just one is bad, the other isn't far behind most likely.
You don't need to turn the tires very fast at all to see the voltage reading. The spec is for just turning them by hand. I seem to remember finding them just by the resistance measurement also.
1. Disconnect front wheel speed sensors
2. Rotate wheel by hand and measure AC mV across sensor.
Reading should be at least 350 mV AC
3. If reading is between 200 and 350 mV AC
Remove speed sensor and plug hole
Clean sensor mounting surface thoroughly
Check sensor for warping/distortion/cracks and check the head for flatness
Spray 2 thin coats of GM 89022217 (89022218 Canada) rust penetrating lube
When dry apply thin coat GM 01051344 (993037 Canada) bearing grease to hub surface and sensor o-ring
Install sensor, or new sensor if necessary
Recheck voltage reading
Hope this helps someone.
ABS kicks in at slow speed
Update to ABS issue
Ok, I tracked my thread from the other Astro site.
Last Friday I took the Astro to a local GM dealer whom I asked if they would clean the sensors after explaining the problem. The quoe was for $100, the vehicle was dropped off and they plugged the fuse back in to enable the ABS. After being unplugged for a while it did not exhibit the problem (don't that drive you crazy). They checked the harness, connections at the sensors etc. Called me that all looks fine and the problem was not their. Oh, the sensors are built into the bearing on this AWD Astro 1996 and cannot be removed (did not mention that on the phone). They had pulled the wheels from what I gathered after my conversation and they last reported that the left wheel bearing had some play and was ok but could be a certification issue later. Not bad enough to write off. However, likely the cause of the problem although they did not experience it.
I picked up the vehicle in what appeared to be a Tornado, trees were snapping and dirt was blowing and water was everywhere. If I wanted to fix the bearing it was only $1300 later. Ahhh ... the next day I was driving around and the symptom slowly started appearing. ABS was kicking in slightly at first just before a stop but a bit of a pulse in the pedal, and more and more with each braking stop. Before I got home I had to stop and pull the fuse. It was not safe since it was nearly back to my last experience and still like that now.
Odd that it works ok after the fuse was pulled though.
Last Friday I took the Astro to a local GM dealer whom I asked if they would clean the sensors after explaining the problem. The quoe was for $100, the vehicle was dropped off and they plugged the fuse back in to enable the ABS. After being unplugged for a while it did not exhibit the problem (don't that drive you crazy). They checked the harness, connections at the sensors etc. Called me that all looks fine and the problem was not their. Oh, the sensors are built into the bearing on this AWD Astro 1996 and cannot be removed (did not mention that on the phone). They had pulled the wheels from what I gathered after my conversation and they last reported that the left wheel bearing had some play and was ok but could be a certification issue later. Not bad enough to write off. However, likely the cause of the problem although they did not experience it.
I picked up the vehicle in what appeared to be a Tornado, trees were snapping and dirt was blowing and water was everywhere. If I wanted to fix the bearing it was only $1300 later. Ahhh ... the next day I was driving around and the symptom slowly started appearing. ABS was kicking in slightly at first just before a stop but a bit of a pulse in the pedal, and more and more with each braking stop. Before I got home I had to stop and pull the fuse. It was not safe since it was nearly back to my last experience and still like that now.
Odd that it works ok after the fuse was pulled though.
Astro AWD LT 1996
315,000km,
rear leaf, tranny cooler, Hercules HP 4000 235P-70/15
CLASS III hitch
Markham, ON, Canada
315,000km,
rear leaf, tranny cooler, Hercules HP 4000 235P-70/15
CLASS III hitch
Markham, ON, Canada
-
dragonvan
Topic author - I get chills without my van.
- Posts: 94
- Joined: Fri Jun 08, 2007 12:29 pm
- Location: WI
Tripp,
According to my manuals the sensors are not built into the hubs on your astro if it is indeed a '96 AWD. I checked and both NAPA and partsamerica.com (Advance Auto Parts) list a separate wheel speed sensor for the '96 AWD and it is definitely not the one for the 2wd.
Ahhh, but the plot thickens.......
All of the aftermarket wheel bearings I can find for your van have the sensor built in. I can't find a listing in the aftermarket for a separate sensor for my '02 and the wheel bearing is the same part number as for your '96. I took a quick peak at my drivers side bearing and the sensor is built in, but I don't know if it is the original or not.
When your van came in with a known problem that has a tsb like this, and the problem is known to be intermittent on many of the vehicles you don't test drive it you perform the diagnostic steps outlined in the tsb. Sometimes there is a diagnostic step saying to duplicate the condition. On this tsb there is not. Even with the sensor being built into the hub, this walks like a flaky sensor, talks like a flaky sensor and they should have performed the voltage measurement to find out if it was a flaky sensor.
I don't know why they didn't just run the voltage test anyway as the spec is the same whether the sensor is removable or not. What really gets me is that this is a major safety concern and they told you to just drive it! Maybe the tech that was working on it was lazy, I don't know. There is no excuse for any GM dealership tech not to know about this problem. It affected over 4 million trucks if I remember right. 75% of non dealer techs probably even know about it. I wish you were closer I would tell you to come over and we would have you back on the road in no time. Having said that I do think that this is something that you could do yourself if you wanted. It isn't that difficult.
You need to find out if they truly checked both bearings as it appears that there is the possibility that one has been replaced and has a permanent sensor and the other is still factory with a removable sensor. Also find out if they did measure the voltage or not and what it was. I have the specs posted above. I always write up on the service ticket the values of any measurements I take. If they're smart they did too.
As far as the problem disappearing after the fuse was pulled and then coming back... It is probably just coincidence as this problem can be intermittent. It's true, you could have some other issue going on, but you need to perform the voltage measurement test on the sensors first to make sure they aren't the problem before you spend hours chasing a bad connection/wire or controller etc.
I still would bet money on the sensors, but even if I'm wrong it is still the place where you need to start.
It is very confusing that GM lists 1995-2003 Astro/Safari on the TSB but that some of them (my '02 most likely) have non-removable sensors. I can see this happening at two different production plants but Baltimore was the only factory. Perhaps the aftermarket didn't want the liability of this problem so after it showed up they stopped making the hubs without the integrated sensor. That may be why the only wheel bearings I can find for the '96 have the sensor integrated in. If I get time in the next day or two I will see what GM has available for sensors and bearings for both the '96 and '02. Maybe we can get even more confused.
Sorry if this post wasn't too helpful.
DV
According to my manuals the sensors are not built into the hubs on your astro if it is indeed a '96 AWD. I checked and both NAPA and partsamerica.com (Advance Auto Parts) list a separate wheel speed sensor for the '96 AWD and it is definitely not the one for the 2wd.
Ahhh, but the plot thickens.......
All of the aftermarket wheel bearings I can find for your van have the sensor built in. I can't find a listing in the aftermarket for a separate sensor for my '02 and the wheel bearing is the same part number as for your '96. I took a quick peak at my drivers side bearing and the sensor is built in, but I don't know if it is the original or not.
When your van came in with a known problem that has a tsb like this, and the problem is known to be intermittent on many of the vehicles you don't test drive it you perform the diagnostic steps outlined in the tsb. Sometimes there is a diagnostic step saying to duplicate the condition. On this tsb there is not. Even with the sensor being built into the hub, this walks like a flaky sensor, talks like a flaky sensor and they should have performed the voltage measurement to find out if it was a flaky sensor.
I don't know why they didn't just run the voltage test anyway as the spec is the same whether the sensor is removable or not. What really gets me is that this is a major safety concern and they told you to just drive it! Maybe the tech that was working on it was lazy, I don't know. There is no excuse for any GM dealership tech not to know about this problem. It affected over 4 million trucks if I remember right. 75% of non dealer techs probably even know about it. I wish you were closer I would tell you to come over and we would have you back on the road in no time. Having said that I do think that this is something that you could do yourself if you wanted. It isn't that difficult.
You need to find out if they truly checked both bearings as it appears that there is the possibility that one has been replaced and has a permanent sensor and the other is still factory with a removable sensor. Also find out if they did measure the voltage or not and what it was. I have the specs posted above. I always write up on the service ticket the values of any measurements I take. If they're smart they did too.
As far as the problem disappearing after the fuse was pulled and then coming back... It is probably just coincidence as this problem can be intermittent. It's true, you could have some other issue going on, but you need to perform the voltage measurement test on the sensors first to make sure they aren't the problem before you spend hours chasing a bad connection/wire or controller etc.
I still would bet money on the sensors, but even if I'm wrong it is still the place where you need to start.
It is very confusing that GM lists 1995-2003 Astro/Safari on the TSB but that some of them (my '02 most likely) have non-removable sensors. I can see this happening at two different production plants but Baltimore was the only factory. Perhaps the aftermarket didn't want the liability of this problem so after it showed up they stopped making the hubs without the integrated sensor. That may be why the only wheel bearings I can find for the '96 have the sensor integrated in. If I get time in the next day or two I will see what GM has available for sensors and bearings for both the '96 and '02. Maybe we can get even more confused.
Sorry if this post wasn't too helpful.
DV
Scanned via computer
Yep the Rep confirmed the monitored it in a road test via the computer and volt was within spec's. Also based on VIN # the vehicle was built with hub based sensors built-in. I have seen theses bearing on ebay but getting it from the US could be costly for customs etc. as they ship UPS which has high brokerage charges. I have not checked with local sourse yet. But may later on.
As per earlier note. GM customer service did NOT bat an eye on this problem. Only said that based on the year and millage there is nothing we can do. Acknowledged no recalls or special alert for ABS issues on Astros hear in Canada. But my buddy had a 3/4 ton Silverado which has a similar bearly fall in a2003-2004, not sure of the year now and numerous other problems like fish wire power window frame fell apart. This was a fully loaded 4x4 w/long box and cost a mint. Got no warranty consessions etc & $$$ repairs. Now he is driving a Ridgeline after two decades of GM trucks!
In my customer service returned call by PR I clearly indicated I would not be buy another GM. I have a Caravan 97, Jeep Grand 02 on the road. Eagle summit AWD (off the road was using too much oil and already had engine rebuild). No wonder imports are overtaking them.
As per earlier note. GM customer service did NOT bat an eye on this problem. Only said that based on the year and millage there is nothing we can do. Acknowledged no recalls or special alert for ABS issues on Astros hear in Canada. But my buddy had a 3/4 ton Silverado which has a similar bearly fall in a2003-2004, not sure of the year now and numerous other problems like fish wire power window frame fell apart. This was a fully loaded 4x4 w/long box and cost a mint. Got no warranty consessions etc & $$$ repairs. Now he is driving a Ridgeline after two decades of GM trucks!
In my customer service returned call by PR I clearly indicated I would not be buy another GM. I have a Caravan 97, Jeep Grand 02 on the road. Eagle summit AWD (off the road was using too much oil and already had engine rebuild). No wonder imports are overtaking them.
Astro AWD LT 1996
315,000km,
rear leaf, tranny cooler, Hercules HP 4000 235P-70/15
CLASS III hitch
Markham, ON, Canada
315,000km,
rear leaf, tranny cooler, Hercules HP 4000 235P-70/15
CLASS III hitch
Markham, ON, Canada
-
dragonvan
Topic author - I get chills without my van.
- Posts: 94
- Joined: Fri Jun 08, 2007 12:29 pm
- Location: WI
Monitoring the voltage on the Tech 2 during a road test is not the same as performing the check in the tsb. The sensor values drop too quickly to show up with the slow data bus. That is part of the reason no code is set.
GM Canada better shape up if they want to keep selling cars. I don't blame you for being upset. My dad likes Chrysler minivans. It keeps me busy. My brother in law works as a Chrysler tech. When Chrysler builds a decent trans maybe I would look at one. Of course that would be more than 5 years away as it will take at least that long for the Astro to rust out and I don't buy very new vehicles. I like my 2 suzukis, metro and tracker. Both get drove hard, Tracker is lifted and off-roaded hard. I can't seem to kill them and I have worked on a lot of them for piddly stuff but only time I've done major work on them was due to abuse/neglect (you mean the timing belt needs to be changed before 180k). I really like the Honda and Toyotas as well. Their engines are a work of mass production art.
GM Canada better shape up if they want to keep selling cars. I don't blame you for being upset. My dad likes Chrysler minivans. It keeps me busy. My brother in law works as a Chrysler tech. When Chrysler builds a decent trans maybe I would look at one. Of course that would be more than 5 years away as it will take at least that long for the Astro to rust out and I don't buy very new vehicles. I like my 2 suzukis, metro and tracker. Both get drove hard, Tracker is lifted and off-roaded hard. I can't seem to kill them and I have worked on a lot of them for piddly stuff but only time I've done major work on them was due to abuse/neglect (you mean the timing belt needs to be changed before 180k). I really like the Honda and Toyotas as well. Their engines are a work of mass production art.