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1995 Deville 4.9L 200,000m
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498 Posts
Discussion Starter #1
1995 Deville 4.9L

Codes:

P039 HISTORY - Torque Coverter Clutch/Viscous Converter Clutch Engagement Problem (I'll get to that later.)
I039 HISTORY - (Loss of Road Sensing Suspension Data - I assume this is from having passive struts, not concerned.)
T027 CURRENT - LF Wheel Speed Sensor Continuity Fault (I've tested the circuit for continuity, checks out.)
T025 HISTORY - LF Wheel Speed Sensor Fault (Replaced hub)
T077 HISTORY - ???

Sometimes the warnings come on as soon as I start, sometimes after driving a bit.

Interesting note: I cleaned the break valve off with engine cleaner and the lights didn't come on for about a day and a half.

I have not yet tried switching relays or cleaning the pump ground.

Anyone know what code T077 is?
 

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2011 CTS4 Premium, Saturn Vue XR
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493 Posts
Never heard of T077 code...try resetting your codes and see if it comes up again. If its (History) code could be just temporary.
 

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99 STS
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3 Posts
I have a 99 STS that does the same thing. The ABS, Traction Control,Fog lights, heated seats, blowers for a/c and heat, and functions on the rear view mirror all kick off and on at their own will---drives me nuts. Let me know if you find a solution.
 

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1995 Deville 4.9L 200,000m
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498 Posts
Discussion Starter #4
Never heard of T077 code...try resetting your codes and see if it comes up again. If its (History) code could be just temporary.
I have, many times, this has been going on for months. It seems like it started last time I had my emissions checked and the guy had to dissable the TC to put it on the dynamo. I've even recently disconnected the battery to install a new blower motor (rediculously expensive).

I will double check the T077 though...

I just hope it's not the control valve or the control module, those things look extrememly expensive.

Tonight I'll clean off the ground on the pump and make sure it has a good connection.

I'll try the relay switch if that doesn't work.

I'm thinking the engine cleaner shorted the ground to the chassis and once it and the water dried I got a ground fault again.
 

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1995 Deville 4.9L 200,000m
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498 Posts
Discussion Starter #5
Yep, T077. This is a new one to me too, first time I've seen it is just before I made my original post.

Hopefully if I can find out what it means it will steer me in the right direction.
 

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1995 Deville 4.9L 200,000m
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498 Posts
Discussion Starter #8
The T077 was a com fault. Never seen it again.

I replaced the ABS pump with one from Pull-A-Part, I've replaced they hub (including WSS), now it takes a little longer for the light/warning to come on.

I just got a vacuum pump because after replacing the ABS and bleeding it I noticed it was nasty.

I was just wondering if there was any chance a flush might help.
 

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1995 Deville 4.9L 200,000m
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498 Posts
Discussion Starter #9
Could a bad break master cylinder cause these warnings?

I noticed something driving on ice this week, since Atlanta doesn't have equipment to clear the roads...

The ABS light and traction control dissabled warning don't come on if I'm very sparing with the breaks. If I break hard, usually the first time I break hard when there is still no warning, the pedal will seem to vibrate as it goes almost to the floor. If I let off and re-apply the break this goes away. The light and warning will come on then or not long after.

It kinda feels like the piston is slipping inside the cylinder but I've never had one go bad so I'm not sure.

Any thoughts?
 

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2010 DTS
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87,564 Posts
I don't think a bad master cylinder will set any codes as it is not electronically monitored, but if the pedal goes to the floor and there is no air in the system and no external leaks, then the master cylinder is probably bad (piston leaking internally).
 

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1995 Deville 4.9L 200,000m
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498 Posts
Discussion Starter #11
I've never had to replace any break fluid. So that isn't my abs pump freaking out or something.

I was think that if the break system knows I'm pressing the break and the wheel speed sensor doesn't sense the speed decreasing, might that cause a WSS fault? Which I have, and I've replaced the whole hub.

A WSS sensor problem will disable ABS and TC, won't it?
 

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2010 DTS
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I was think that if the break system knows I'm pressing the break and the wheel speed sensor doesn't sense the speed decreasing, might that cause a WSS fault?
No, a WSS fault is caused when the PCM detects an open circuit or the wrong resistance I believe.

A WSS sensor problem will disable ABS and TC, won't it?
Yes.
 

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1995 Deville 4.9L 200,000m
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498 Posts
Discussion Starter #13
It's got to be in the wiring, then. I tested the circuit for continuity and it seemed OK.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Your post a while back - about the brake pedal vibrating if you have to depress it almost to the floor - that's ABS operating - you should also hear it work. It's not subtle - ABS rapidly pulses the brakes for maximum stopping power BUT does not allow wheel lockup.

If your brake fluid is in fact dark and nasty, you should exchange it ASAP. Brake fluid LOVES moisture, which is what turns it dark, and if that's the case then you'll soon be in for some scary expensive brake system work. In any car you should exchange the brake fluid every 3 - 5 years.
 

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1995 Deville 4.9L 200,000m
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498 Posts
Discussion Starter #15
I've already flushed the fluid.

When it vibrates and goes to the floor there are NO brakes, I have to pump them once to get it to stop.

It doesn't do it when I NEED ABS, for example, yesterday morning it did it while I was making a right turn.

Thank god it doesn't happen when I really stomp on them at 85 mph on the interstate. I'd be dead.

There's not much rhyme or reason to it, except that it tends not to do it when I break lightly. I made it almost 55 miles to work without it coming on the other day.

I sure wish I could figure this out, it's the last major problem I need to fix on this car.

:hmm:
 

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When it vibrates and goes to the floor there are NO brakes, I have to pump them once to get it to stop.
Sure sounds like a bad master cylinder to me (assuming there are no external leaks). Does the pedal stay up when you pump it or does it slowly sink to the floor again?
 

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1995 Deville 4.9L 200,000m
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498 Posts
Discussion Starter #18
It breaks normally after I let off the pedal then press it again. And this only happens occasionally.

I had a thought this morning, all my traction control disabled problems started after an emmission inspection. The inspector seemed to be having a very tough time disabling the TC with the button in the glove box and it's never worked right since. Could he have broken my TC dissable switch and could that be causeing it to dissable?
 

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The T/C disable switch could be stuck on, but that would not explain a sinking pedal. THAT is either an external leak or a bad master cylinder leaking internally.
 

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1995 Deville 4.9L 200,000m
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498 Posts
Discussion Starter #20
My T codes come and go now, sometimes it says NO DATA sometimes it's LF WSS/COMM Fault.

I'm thinking this might be a wiring issue. I've changed the BPMV/EBTCM with a junk yard part and it behaives pretty much the same. The warnings seems to come up faster, though.

There's a '95 that only been at my local yard for a few days, I might go pull just the EBTCM and the whole damned engine electrical harness. Then I could test each conductor for continuity and shorts.

It doesn't seem like I'm using my front brakes at all, either.

Any other suggestions?
 
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