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ABS TCS and Brake Warning light on


Ken0359
03-19-2008, 08:43 PM
I have a 1998 chevy venture and The brake warning light, TCS, and ABS lights on the instrument panel are all on. I took it to my mechanic and the scan code was C1246. The shop came to the conclusion that it was probably the Motor Pack on the ABS unit. But due to the cost of 400.00 plus labor for a motor pack kit from GM and the possibility of being another component I did not have the van repaired yet.

One of the things I noticed if I push the brake pedal down and hold it there start the engine the lights go one for the brief moment then go off like most cars do. As soon as I release the pedal I here the ABS unit clicking under the hood and all three warning lights come on leaving me with a regular brake system.

Does anyone have any thoughts or experience on this problem.

SEMORiverHills
03-20-2008, 12:29 PM
Hi Ken,

Based on my very recent experience, I would say that the likelihood of a code indicating the ABS Motor Pack is bad is quite high.
I have a 98 Venture that, up until 2 days ago, had the same three lights on as you have. I had the code pulled by a local, reputable dealer where I know the manager personally, and it said the ABS Motor Pack was bad. They told me the chances of the Motor Pack being the actual root cause of my problem were very good, as the Motor Pack is notorious for failure on the Delco ABS-VI system (which is what the ABS system is on our vans). A little research for myself supported what their recommendation.
I was able to get the motor pack from a local salvage yard (also came with Master Cyl, Brake Fluid Reservoir, ABS Modulator, and TCS Motor/Modulator - they would only sell all together) for the very reasonable price of $75. Way better than the $314 wholesale price I was quoted for a new Motor Pack through GM.
I did the replacment 2 nights ago, and no lights ever since. BRAKE light went out right away, and ABS & TCS lights went off after 1 trip, shut down, restart.
One quick note:the dealer tech discovered that due to the malfunction of my Motor Pack, my left rear wheel wasn't braking at all. So, contrary to what I thought for the 1 year + that I had those lights on, this was a pretty serious, fundamental safety issue.

I hope this helps.

Andy

SEMORiverHills
03-20-2008, 12:38 PM
Ken, I forgot to address the clicking of the ABS sytem at startup that you mentioned. The clicking you hear is the self-check that the ABS system performs at every start-up. If you hold your foot on the brake when you start the van, the ABS system will not execute this check until you let off of the brake. The lights don't come on until you let off the brake, because the system hasn't done the self-check yet. Once the self-check is completed, and a problem is detected, the lights come on. My van, along with my 1995 Grand Prix, which both have the ABS-VI system, do the same self-check and make the same type of noise at start-up. It's understandable to perceive the noise as abnormal; when I test drove the Grand Prix 7 years ago, I thought something was wrong.

Andy

Ken0359
03-20-2008, 12:50 PM
Thanks for the info.

GM Parts Direct sells the motor pack for 263.00 shipping included. I may go that way if I cant get one from a junk yard. If the motor pack is prone to failure it seems a new one would be the way to go. My mechanic told me there has to be a calibrated distance set with feeler gages. Since you had bought a used assy sounds like you did not have to deal with that.

SEMORiverHills
03-20-2008, 01:03 PM
Although I got the whole assembly, the only component I changed out was the Motor Pack. I simply removed the three Torx head screws to remove the cover on the bottom, and two Torx head screws to release the motor pack from the ABS modulator, and pulled it down and out. Putting the used motor pack in was an exact reverse of removal - totally "plug-n-play" so to speak. No adjustments at all. Maybe it's different if you buy a brand new motor pack...?

My van has 197,000 miles on it, and only needs to get my family by for another 2-3 years, so I decided to take my chances on the used motor pack. Even if this one fails eventually, it's less than an hour's work to change, and for the price I can put in 2 more used ones by the time I pay the $$$ for a new one. Just my $.02

Andy

Ken0359
03-20-2008, 01:21 PM
Sound good. I will look for a used one first. My venture has almost 174,000 and Runs great. I wouldn't hesitate to take a trip across the country with it. Thanks for your info.

SEMORiverHills
03-20-2008, 02:09 PM
No problem. I feel the same about my van, at least now that the head gasket job is completed (just did that back in Dec. - approx. 3,000 miles ago).

Ken0359
03-20-2008, 08:36 PM
I have one more question. Did you have to undo the brake lines and remove the ABSMaster cylinder assy because it looks pretty tight around the ABS/Motor Pack

SEMORiverHills
03-21-2008, 12:32 AM
No need to open the brake lines to the ABS Modulator - in fact, that's something that you don't want to do! My understanding is that if you open those lines, air will be introduced into the ABS Modulator, and a special procedure is required to bleed that unit (use of Tech II Scan Tool to cycle the ABS "valves" to force the air out of the bleed screws located on the modulator).
At first glance, the motor pack (along with almost any component on this engine :lol: ) looks like a very tight squeeze, but it is very do-able. The brake lines leading to the ABS Modulator will flex some, and that combined with the correct items removed from the surrounding area, will allow just enough room to pull the ol' Motor Pack out of there.
Components that will need to be removed, in the order in which I did it:
1. Coolant Reservoir
2. Cruise Control Modulator (no need to remove it altogether, just unbolt the bracket from the fender, and remove the modulator from the bracket). This allows you to get to the brace that runs from the radiator support to the fender.
3. Above-mentioned brace
4. Air Intake Duct
5. Air Cleaner Element
6. Unplug ECM and carefully lay out of the way (I laid it on the radiator support, and was extremely careful around it while it lay there).
7. Air Box
This should allow you enough clearance to flex those lines just a bit and get that motor pack pulled out of there. Getting at the 3 Torx cover screws and the 2 Torx screws holding the motor pack to the modulator isn't too tough at removal, but it takes a little time and finesse to get them started again upon reassembly. You might have to lightly tap around the perimeter of the cover with screwdriver handle or such to shock it off of the motor pack, even after the screws have been removed.

I hope this helps. Pretty easy for me to spout off these details since I just tackled this one a few nights ago.

Let me know how it turns out.

Andy

Ken0359
03-21-2008, 07:18 AM
I've done alot of different mechanical operations to my autos (ie clutches brakes, intake manifold gaskets etc.) It must be an age factor. Hitting the 49 tomorrow. Thanks for your input.

Debi C
03-21-2008, 07:58 AM
My ABS and TCS lights were on as well..I had a board replaced on my tail light and they went out.

However now my hazard lights are always lit on my dashboard, when I press on the brake they go dimmer, and my radio light flickers with the pressing of the brake or when the turn signal is on. And when I turn on my turn signal on my hazard lights either stay lit constant or click/flash very fast.

I also just found out I have no tail lights or brake lights at all!

Do you have any clue?

Thanks,

Debi

SEMORiverHills
03-22-2008, 03:23 PM
Debi, have you had you van scanned for ABS Trouble Codes? If so, what did the code indicate?
As far as changing out the rear tail lamp assy - I have heard of ABS/TCS lights being related to that. Someone who I remember posting a lot of very helpful information about that is an AF Member who goes by cjstew I believe.
As far as different interior lights acting abnormal when your turn signals are on, etc - I've read on the forum about an electrical connector under the carpet that can get wet and go bad, causing some weird electrical situations. Unfortunately, I can't be much help on that, as I haven't crossed that bridge yet with my Venture.

Andy

cjstew4
03-24-2008, 05:53 PM
Debi, here I am, the cjstew4 that Andy mentions. I would definitely first take it too an AutoZone or similar place that lets you borrow the code reader and read and give them the codes to know if it is the short in the rear taillight connection b4 I would tackle that. If it happens to be it, here are the instructions on the cheaper/cheapest fix if you are handy with repairs such as these:

You'll have to open the tailgate and pull off your rear taillight housing that
should be held on by two star head bolts, but I am not sure of the size. If
you don't have those sockets, then sometimes a flathead screwdriver of the right size can loosen them if they are not too tight. Once off, you will see a
harness with a connector on the end that plugs into the circuit board connector.

You can see how GM designed this so that the water flows right into it. Unplug the connector that has about 5 different clored wires as part of the harness and you will see the shorted black wire in the middle of the connector. That's your problem. A shorter way than mine at this point left by another poster was to drill out the burned black wire/connector section and
screw in a 10 gauge wire in it's place and connect to the opposing harness
ground wire (black one, thicker one).

If you prefer my option which costs about $5 is to label the harness wires
that plug into the circuit board as to their location on the mating plug, cut the plug off the harness, attach connectors to each wire, cut down all 4 sides of the circuit bd plug about 3/8th to 1/2 in exposing the 5 pins. Be sure to clean off the shorted middle, thin prong/pin carefully. Attach the mating connector from the location markings you did earlier. Test the brakes, notice
that your ABS/TCS dash lights are now out (not lit anymore), and apply weatherproof silicone to the connections so that water, etc cannot collect at the harness or connections.

Call me at my cell if you need further assistance. 619-890-2118 (Pacific time zone). Good luck, Corey.

Nitro23
04-02-2008, 09:44 AM
Which tail light do you remove - Driver or Passenger? Or do you have to check both?

cjstew4
04-02-2008, 03:56 PM
Which tail light do you remove - Driver or Passenger? Or do you have to check both?

You want to remove both since even if only one side is bad the other may not be far behind it. It reworked both for my 97's repair and weatherproofed/gooped up that whole harness /plug assembly after I tested them. Been 2 yrs now w/o an issue.

afc1903
10-11-2008, 06:41 PM
Hi, i've just repaired my 1999 chevy venture LS thats had the ABS light and brake warning lights on. I used a scan tool and got the code c1246 and " rear channel will not lock " after reading the posts on this web site I've replaced the ABS motor / master cyl ,my venture does not have tcs so it is the complete unit that i replaced and had to Bleed the brake system at the ABS motor 2 places and at each wheel. I got a used ABS motor for $35.00 so i'm really pleased. Thank you all for the previous posts they were really helpful cheers Rich.....

horshackk04
10-22-2008, 05:50 PM
another simple check is to check the wiring harnass that go,s to the abs wheel sensor, there is a quick connect connector that is located on the lower a arm beside the tie rod spray with contact cleaner and ad a little bit of dielectric grease. In my case the harnass came loose and was rubbing on the axle boot, i had to splice in a small piece of wire and was good to go.

olds_77_88
11-02-2008, 08:49 PM
I have a 1998 chevy venture and The brake warning light, TCS, and ABS lights on the instrument panel are all on. I took it to my mechanic and the scan code was C1246. The shop came to the conclusion that it was probably the Motor Pack on the ABS unit. But due to the cost of 400.00 plus labor for a motor pack kit from GM and the possibility of being another component I did not have the van repaired yet.

One of the things I noticed if I push the brake pedal down and hold it there start the engine the lights go one for the brief moment then go off like most cars do. As soon as I release the pedal I here the ABS unit clicking under the hood and all three warning lights come on leaving me with a regular brake system.

Does anyone have any thoughts or experience on this problem.
My 97 venture has the same problem. Abs Tcs lights on since last winter when the wife ran into the ditch off an icy road. We just ignore it it dosent hurt anything. I just figured they came on because it got jard in the crash,,,

cjstew4
11-03-2008, 04:55 PM
My 97 venture has the same problem. Abs Tcs lights on since last winter when the wife ran into the ditch off an icy road. We just ignore it it dosent hurt anything. I just figured they came on because it got jard in the crash,,,

One of your rear brake lights may be out due to the infamous rear tailight harness to plug shorting at ground. When you press the brake pedals do both directional arrows light up dimly? I would still make sure all brake lights work.

Schrade
11-05-2008, 11:10 AM
The shop came to the conclusion that it was probably the Motor Pack on the ABS unit. .

:lol2:

Probably. :lol:

Okay, sounds great. If it fixes it, I'll probably pay you uh huh. If it don't, well, ain't no probably about it. I WON'T.

Probably. :lol:

Just tell them to print out the diagnostic testing procedure from ALL DATA, or Mitchell's, or whatever they have, and buy a multimeter on the way home, and then do the tests as described, and if you're lucky, you'll find the chafed wire that you can fix for .06 cents' worth of electrical tape, which is causing the problem.

greaabb
03-03-2009, 06:41 PM
Andy,

I know its been a year since you lasted posted here, but do you still have the TCS modulator that you got from the junkyard? I am looking for one.

George

rockwood84
03-09-2009, 10:54 PM
a shorted out or wires broke on a wheel sensor will make the same three lights come on the dash.my wife ran through where a deer had been ran over by a semi and i guess the lab puppy she had at the house had to check out the underneath of the van when she got home.it ended up chewing one of the elbows on the rear wheel sensor wires .when i went to drive to town the next morning the trhee lights came on in the dash.i still had brakes but not abs. i check the fluid level which was full then started checking wires and found the chewed spot. so check and see if a wheel sensor connector has been knock loose or if the wires going to one is damaged.

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