ABS failed

So here I am driven 50 on the freeway, all of the sudden the car feels like its loosing all its power and the brakes feel like they are being applied and let off and applied and let off. Im not even touching the brakes. I pull over and sit a moment, then take off as normal. This time got up to 40 and it started doing the same thing. I limp home at 35 and no problem. The check engine light is on, so I get the shop to pull the codes. They tell me it is the ABS pressure modulator valve. Anybody ever had this problem? They tell me I can only get this part from the dealer and its very exspensive. Anyway Im gonna check with ED on ebay and see if he has one.

[quote="YO MUDA"]So here I am driven 50 on the freeway, all of the sudden the car feels like its loosing all its power and the brakes feel like they are being applied and let off and applied and let off. Im not even touching the brakes. I pull over and sit a moment, then take off as normal. This time got up to 40 and it started doing the same thing. I limp home at 35 and no problem. The check engine light is on, so I get the shop to pull the codes. They tell me it is the ABS pressure modulator valve. Anybody ever had this problem? They tell me I can only get this part from the dealer and its very exspensive. Anyway Im gonna check with ED on ebay and see if he has one. [/quote

I agree, Morad's your best bet initially, if he does not have there are other parts dealers on the Rivperformance list (Wilberts, etc).

Albertj

This is just off the top of my head, but I would be more inclined to think it was the EBTCM going nuts. If a valve was sticking/applying when it shouldn't be, it would hold the brakes after you've applied them. But if the system is applying by itself, then the TC motor/pump would have to be running - like when it does the self-test at 12 MPH and the pedal goes high & hard...

In the meantime, so you can drive the car, pull any ABS/TC fuses out.

There is no such code that just says YOUR MODULATOR IS BAD. There is a bit of testing to be done in order to rule that part out. It is the most expensive part in the ABS system, so don't go ordering anything yet.

Did they tell you the code(s)??

They didnt give me the codes

Well, you don't have your year & engine in your signature line yet, (hint-hint) but these are the possible codes in the '98 book:


DTC C1211 Valve Supply Voltage Interruption
DTC C1215 Suspect Valve Malfunction

DTC C1221 RF Wheel Speed Sensor Circuit Open or Shorted
DTC C1222 RF Wheel Speed Sensor Signal Intermittent
DTC C1223 RF Wheel Speed Sensor Signal Missing
DTC C1225 LF Wheel Speed Sensor Circuit Open or Shorted
DTC C1226 LF Wheel Speed Sensor Signal Intermittent
DTC C1227 LF Wheel Speed Sensor Signal Missing
DTC C1231 RR Wheel Speed Sensor Circuit Open or Shorted
DTC C1232 RR Wheel Speed Sensor Signal Intermittent
DTC C1233 RR Wheel Speed Sensor Signal Missing
DTC C1235 RR Wheel Speed Circuit Open or Shorted
DTC C1236 LR Wheel Speed Sensor Signal Intermittent
DTC C1237 LR Wheel Speed Sensor Signal Missing

DTC C1241 RF Inlet Valve Circuit Malfunction
DTC C1242 RF Outlet Valve Circuit Malfunction
DTC C1244 RF Isolation Valve Circuit Malfunction
DTC C1245 LF Inlet Valve Circuit Malfunction
DTC C1246 LF Outlet Valve Circuit Malfunction
DTC C1248 LF Isolation Valve Circuit Malfunction
DTC C1251 RR Inlet Valve Circuit Malfunction
DTC C1252 RR Outlet Valve Circuit Malfunction
DTC C1255 LR Inlet Valve Circuit Malfunction
DTC C1256 LR Outlet Valve Circuit Malfunction

DTC C1261 Pump Motor Run Malfunction
DTC C1262 Pump Pressure Malfunction During ABS Stop
DTC C1271 EBCM/EBTCM Internal Malfunction
DTC C1272 Brake Travel Switch Circuit Malfunction
DTC C1273 BPMV Fluid Level Switch Circuit Malfunction
DTC C1274 BPMV Pressure Switch Circuit Malfunction
DTC C1275 PCM Requested TCS to Be Disabled
DTC C1276 Serial Data Malfunction

DTC C1277 Delivered Torque Signal Circuit Malfunction
DTC C1278 Requested Torque Signal Circuit Malfunction
DTC C1281 Brake Thermal Model Limit Exceeded

YO MUDA wrote:

They didnt give me the codes

Please try and get them. The ABS Modulator Valve is quite rare to go bad. 95% of the time it's the EBTCM that goes haywire.

Eldo, Jesus man........

Abaddon wrote:

Please try and get them. The ABS Modulator Valve is quite rare to go bad. 95% of the time it's the EBTCM that goes haywire.

Actually, the modulator assy on our '92 LeSabre died at about 20,000 miles... but we said screw the $1200 price tag, we still had normal brakes.

Quote :

Eldo, Jesus man........

What?

I'll get the codes tomorrow. Thanks for the help.

In the meantime, so you can drive the car, pull any ABS/TC fuses out.
Where are these fuses located?

Check all 3 - Dashboard, underhood and back seat... I know there are associated fuses in at least two of them.

Eldo wrote:

What?

You wrote down every ABS code lol.

I'm sure he just did a copy/paste.

He told me it was a code 74.

Abaddon wrote:

Eldo wrote:

What?

You wrote down every ABS code lol.

So you mock me instead of giving me a plus?
FINE! I'm taking my codes and going home...

YO MUDA wrote:

He told me it was a code 74.

Thanks for filling out your Sig file.

Now, the fact that it's a '95 makes my info more precarious... If we were to take that as meaning a C1274, it doesn't even make sense. That's a pressure switch malfunction, during braking, and the FSM says:

* The pressure switch monitors primary brake system pressure. The switch, normally closed, opens when the brakes are applied and pressure exceeds 700 kPa (101 psi).

* If the brakes are applied manually during traction control mode, the BPMV pressure switch input, along with the brake switch input, signal the EBTCM to disable traction control and allow manual braking.

In other words, that switch only DEactivates the automatic systems when you're trying to regain manual control...

Eldo is half right, so he gets a +

Code 74 will set when the EBTCM detects an open in ckt #853 or ckt #1659, a short to ground in ckt #1659 with the brakes applied, or a failed PMV pressure switch.



The flow chart is 3 pages long. I'll post if you'd like. By the schematic, it appears that the TCC/Antilock Brake Switch could set this code also (ckt 853).
Also, check the HZRD/STOP fuse in the block under the back seat.....

Abaddon wrote:

Eldo is half right, so he gets a +

Thanks!

So, is the '95 code really just 2 digits?

I removed the ABS fuse from under the hood. Now the ABS warning light is on and its still doing the same thing. I may just have to give in and pay a dealer to look at it.

Eldo wrote:

So, is the '95 code really just 2 digits?

OBD I technically, so yes 2 digits.

YO MUDA wrote:

I removed the ABS fuse from under the hood. Now the ABS warning light is on and its still doing the same thing. I may just have to give in and pay a dealer to look at it.

Not the ABS fuse. Check the HZRD/STOP fuse under the backseat. If it is blown it could be causing an issue....

Okie dokie.

The HDRZ/STOP fuze is good. When I drive it from a dead stop,normal acceleration, and I get to around 50, their is a loud thud, but the car is still driving fine. Then somewhere between 50 and 55 the car starts bogging down and it fells like the breaks almost locks down. Then it drives normal for a few minutes and does it again. It kinda reminds me of someone pulling up a hand break. Do ya think this car may be haunted? LOL

Scott, if he pulls all the ABS/TC fuses, shouldn't he have normal brakes?

Eldo wrote:

Scott, if he pulls all the ABS/TC fuses, shouldn't he have normal brakes?

yes, thats how my car is.

YO MUDA wrote:

The HDRZ/STOP fuze is good. When I drive it from a dead stop,normal acceleration, and I get to around 50, their is a loud thud, but the car is still driving fine. Then somewhere between 50 and 55 the car starts bogging down and it fells like the breaks almost locks down. Then it drives normal for a few minutes and does it again. It kinda reminds me of someone pulling up a hand break. Do ya think this car may be haunted? LOL

This seems more like the TC system engaging from inaccurate wheel speed sensor readings. Nearly the same exact thing happened to me when I put larger tires in back vs. front.

Does it happen when you deactivate traction control?

Have you upgraded the wheels or tires recently?