Pontiac Grand Am Abs System Type [Archive] - GrandAmGT.com Forum

PDA

View Full Version : Pontiac Grand Am Abs System Type


hella_fyne07
12-24-2008, 04:22 PM
Hello I was just wondering with my 2004 Pontiac Grand Am Gt are they equipped with either a 3-channel ABS system or 4- Channel ABS System. Ans does Pontiac(GM) use either Bosch or Continental braking system in our cars.

PhantomLover007
12-24-2008, 08:26 PM
Damn. Talk about not posting much.... lol lol

Sorry OT..

gagt Mechanic
12-24-2008, 10:29 PM
I think 4 channel and bosh

AaronGTR
12-25-2008, 09:11 AM
Hello I was just wondering with my 2004 Pontiac Grand Am Gt are they equipped with either a 3-channel ABS system or 4- Channel ABS System. Ans does Pontiac(GM) use either Bosch or Continental braking system in our cars.

No such thing as three channel. It's either 2 or 4.

2 channel it monitors wheel lock on all 4 wheels and if it senses a difference between the front and back, it pulses the ABS solenoid for either both front wheels or both rear wheels. That is how the GA is setup. It has four wheel speed sensors, but only two solenoids, one for the front wheels and one for the rear.

4 channel has four solenoids and can activate the ABS for each individual wheel independent of the others. That's the type you hear about in advertisements for a lot of newer higher end cars, when they say they have 4 channel anti-lock brakes.

And yes I believe our system is from Bosch.

hella_fyne07
12-25-2008, 01:51 PM
Okay thanks guys. AaronGTR there is such thing as a 3-channel Abs system. n a 3-channel ABS system hydraulic pressure is supplied to the front brakes individually, and is supplied to both rear brakes as if there were only one, although wheel speed is measured at all four wheels individually. This system is less complicated and cheaper to build but is does not provide as much safety and control as a 4-channel ABS.

hella_fyne07
12-25-2008, 01:55 PM
Also to clarify Grand Am's have whats called 2 Channel 4-wheel Criss-cross It consists of 4 ABS sensors (one on each wheel) and 2 ABS channels arranged in a Criss-cross (Left Front & Right Rear, Right Front & Left Rear). When the right rear wheel locks up, the left front wheel & right rear wheel are pulsed together.

hella_fyne07
12-25-2008, 03:20 PM
Well Ive been doing a little research and I found out all the information if anyone was interested. The Pontiac uses Delco, Now known as Delphi, instead of Bosch which is used exclusively on GM applications. We use what is called the DELPHI DBC-7 ABS (4-wheel Nonintegral with optional traction control) system in out cars This ABS System was introduced on the 1999 Pontiac Grand Am GT model and was offered on all other Grand Am's in 2001+ models.

The Delphi DBC-7 ABS antilock brake system was first used in 1999 on 1999 Buick Regal and Century, and Chevrolet Tracker. The system replaced the earlier Delphi ABS-VI (which has been around since 1991 on many General Motors passenger cars). For model year 2000, the new DBC-7 system was added to the Chevrolet Impala, Monte Carlo, Malibu, Cavalier and Venture, Pontiac Sunfire and Montana, and Oldsmobile Cutlass and Silhouette.

Like other late model ABS systems, DBC-7 is a compact, lightweight, low-cost ABS system that combines the controller and valve body in one assembly. It is a nonintegral, four-wheel system for either three or four channel operation, and offers traction control capability.

DBC-7 is totally different than the ABS-IV system GM has used on so many of its passenger cars. Gone are the gear pack and motor driven pistons. DBC-7 uses solenoid valves like other ABS systems manufactured by Bosch, Kelsey-Hayes and Teves, and the controller, valves, solenoids and pump are combined into one compact unit.

The valves and pump are mounted in a metal block called the "Brake Pressure Modulator Valve" or BPMV. This is bolted to the "Electronic Brake Control Module" or EBCM that houses the controller, relay and solenoids that actuate the ABS valves. The unit can be taken apart so the BPMV or EBCM can be replaced separately if needed.

The Brake Pressure Modulator Valve has one inlet (apply) valve and one outlet (release) valve for each brake channel, plus two accumulators (one for each brake circuit). So the BPMV contains a total of six ABS valves for three channel system applications, eight ABS valves for four channel systems, or 10 ABS valves if the vehicle has TCS traction control. The inlet valves are normally open, and the outlet valves are normally closed. The solenoid for each valve is energized when the EBCM provides a ground to complete the circuit.

The GM passenger car applications are all four channel ABS systems, so each of the four BPMV outlets is connected to the brake line for a separate wheel. The lines are color coded for identification: left rear is purple, right rear is yellow, left front is red, and right front is green

hella_fyne07
12-25-2008, 03:22 PM
More interesting facts if your a nerd like me.
Something you won't find on a DBC-7 equipped vehicle is a brake proportioning valve. DBC-7 uses the ABS solenoids to reduce pressure to the rear brakes during normal braking to maintain proper brake balance. This is done by monitoring front and rear wheel speeds, and reducing pressure to the rear brakes as needed when there's a difference in wheel deceleration rates.

The controller energizes the inlet valve solenoids for both rear brakes to hold pressure in the lines, and then energizes both rear outlet valve solenoids to release pressure as needed. The pump may also run to clear the accumulators if a sufficient number of release cycles are required.

The "dynamic" rear proportioning function is enabled at all times unless there is a failure of the EBCM or two wheel speed sensors on the same axle both fail simultaneously (a code C1248 will be set if the system is disabled). But as long as there is at least one functional speed sensor on the front and rear axles, the EBCM can compare the relative speeds of the front and rear wheels.

Another new feature of the DBC-7 is the ability to detect low tire pressure. A tire that is underinflated will have a slightly smaller rolling radius than one that is properly inflated. This will create a difference in the wheel speed sensor reading if the difference in inflation pressure is 12 or more pounds. The EBCM will then turn on the "Low Tire Pressure" warning lamp to warn the driver his tires need attention.

AaronGTR
12-26-2008, 01:15 PM
Also to clarify Grand Am's have whats called 2 Channel 4-wheel Criss-cross It consists of 4 ABS sensors (one on each wheel) and 2 ABS channels arranged in a Criss-cross (Left Front & Right Rear, Right Front & Left Rear). When the right rear wheel locks up, the left front wheel & right rear wheel are pulsed together.

Well, I already know thats wrong. I've serviced my entire brake system before and both front brake lines are connected to one solenoid and both rear brake lines to another solenoid. The system can NOT pulse the brakes independently between left and right wheels. Only between front and back. I don't know why they'd want to do that anyway. If you only had one rear wheel locking up and not any of the fronts, and you start pulsing the front braking on one wheel, you will cause a braking imbalance that will cause the car to rotate... not very safe. They would only want to pulse the front or rear together as a pair.

More interesting facts if your a nerd like me.
Something you won't find on a DBC-7 equipped vehicle is a brake proportioning valve. DBC-7 uses the ABS solenoids to reduce pressure to the rear brakes during normal braking to maintain proper brake balance. This is done by monitoring front and rear wheel speeds, and reducing pressure to the rear brakes as needed when there's a difference in wheel deceleration rates.

This is also wrong. We do have a proportioning valve that is fixed and built into the ABS unit. It says so right in the factory service manual.

Another new feature of the DBC-7 is the ability to detect low tire pressure. A tire that is underinflated will have a slightly smaller rolling radius than one that is properly inflated. This will create a difference in the wheel speed sensor reading if the difference in inflation pressure is 12 or more pounds. The EBCM will then turn on the "Low Tire Pressure" warning lamp to warn the driver his tires need attention.

Our cars don't have this either. My '97 grand prix has a low tire pressure warning light. Grand ams don't.

I don't know where you got all this info from, but some of it appears to be inaccurate, or applies to other cars but not the GA. Either way, if you know so much about it or could find so much info on it, why did you bother asking here to begin with?

PhantomLover007
12-26-2008, 01:31 PM
I was about to say... I don't remember ANY year GA having the TPIS (tire pressure indicator system). A CTIS would be nice to have too, but we don't ... ;crap

Haughee
12-26-2008, 03:17 PM
Why does my 2000 GA GT have a Low Tire Pressure Lamp? I have never seen it illuminate, except for when the guage cluster lights up on start-up.

Mike Jung
12-26-2008, 04:21 PM
I was about to say... I don't remember ANY year GA having the TPIS (tire pressure indicator system)...
Late model '99's with the V6 engine do; such as a GAGT.

(Early models like mine didn't.)

PhantomLover007
12-26-2008, 06:58 PM
My '02 doesn't. Maybe it was an option, IDK.

Mike Jung
12-26-2008, 07:04 PM
My '02 doesn't. Maybe it was an option, IDK.
Yours wasn't a '99 lol

PhantomLover007
12-26-2008, 07:05 PM
:tongue3:

cardude007617
12-26-2008, 09:36 PM
my car has the spot to light up...but iv never seen it on either, and would def not rely on it.

x2 on the why post all this information.... when you asked it in the first place

hella_fyne07
12-27-2008, 08:27 PM
I know I have a tire pressure light on my car. Ive had it go off before for having a low tire.

hella_fyne07
12-27-2008, 08:32 PM
AaronGTR I'm not trying to argue or anything it was just something I was wondering out of curiosity after doing some test driving with bosh and going threw the different systems with Bosh (i.e. ABS, ASL, ESP) I believe you I was just curious.

Mike Jung
12-27-2008, 08:34 PM
I know I have a tire pressure light on my car. Ive had it go off before for having a low tire.
LMAO lol

On a '04 GAGT ?

Was that before or after they took out the lock for the glove box ;)


PS: You have gone through alot of GA's: '00 GAGT, '03 GAGT, '01 GA GT1, '99 GAGT, to now a '04 GAGT ?

geldartb
12-27-2008, 08:58 PM
Late model '99's with the V6 engine do; such as a GAGT.

(Early models like mine didn't.)

yeah i got that little option wish i could get rid of it

AaronGTR
12-28-2008, 11:40 AM
AaronGTR I'm not trying to argue or anything it was just something I was wondering out of curiosity after doing some test driving with bosh and going threw the different systems with Bosh (i.e. ABS, ASL, ESP) I believe you I was just curious.

It's cool, I'm not trying to argue either. I just want people to have the most accurate info possible on here and some of the stuff about the ABS system you posted didn't match what I've read in the factory manual. That's all.


I just got home from traveling for the holidays so I was able to double check my manuals on a few things. For the tire pressure monitoring, there was nothing in my owners manual under warning lights and indicators. In the service manual for 2000 N-bodies it does have a section for a TIM (tire inflation monitoring) system, but it says oldsmobile only. So apparently it was only on the alero and might have been on early GA V6 models but for some reason they decided to delete it on later models. No idea why since everything was already in place for the system to work, but my GA doesn't have the tire pressure system reset button on it like my GP does. Thats probably why there is a spot for a light for it on the gauge cluster though.

I think I might have found what you were referencing though for the front/rear cross braking. It appears to be the master cylinder pistons and not the ABS operation. This the description and operation for the master cylinder.

"This master cylinder is a composite design with a plastic reservoir and an aluminum body. The master cylinder is used in a diagonally split system. In this system, one front and one diagonally rear brake is served by the primary piston and the opposite front and rear brakes are served by the secondary piston.

The master cylinder incorporates the functions of a standard dual master cylinder. The master cylinder also has a fluid level sensor"

So basically what they are saying is the master cylinder has two pistons in one unit so it does the work of two separate master cylinders in one, and each piston provides pressure for one front and one rear brake caliper. There was also this about the proportioning valve.

"The proportioning valve is bolted directly to the ABS hydraulic modulator assembly. The ABS hydraulic modulator assembly is located beneath the battery tray.

The proportioning valve limits outlet pressure to the rear brakes after a predetermined master cylinder pressure is reached. This is used when less rear apply force is needed in order to obtain optimum braking."

Also just in case anyone was wondering, the ABS computer is located on the other side of the frame rail directly opposite the hydraulic modulator assembly, underneath the washer fluid bottle. I hope this sheds a little more light on the topic. :)

2000 GT Coupe
02-18-2009, 10:17 PM
I have a question about ABS I, not knowing enough about these cars obviously, connected the halo lights to a switched powersource under the hood and it happened to be the abs fuse, #36, well my wife drove to work that night and the next morning the abs light was on. Now my guess on this was that while driving abs was needed and there must have been a current draw that was more then available although the fuse was not popped I changed it and moved the halo wires. the abs stayed on I replaced the relay, #11, now when the key is on the abs light goes out but when the car is started it comes back on. Would anyone have any info that might shed some light on that?

2000 GT Coupe
08-12-2009, 03:38 PM
As a note for anyone that may have been wondering I found the problem, it was several different things that were going on at the same time.

I replaced my tail lights and 3rd brake lights with led's. and in order to get cruise to work I added a resister it caused too much resistance in the system I changed the resister to a slightly smaller one and presto.