KevinB03

After seeing the ABS, Active Handling, and Traction Control indicators on for the last several months I brought my 2003 C5 into the dealer and was told there is hydraulic fluid leaking from the BPMV into the EBCM, causing all three indicators to remain on. Can the fluid really leak from the BPMV into the EBCM?

Vetteman Jack

DeeGee

Bill Curlee is the guru on the BPMV/EBCM and how it works but I'll try a holding reply

The BPMV is isolated from the EBCM in terms of hydraulics. Hydraulic fluid comes from the master cylinder and is fed through the BPMV. From the book "The BPMV contains the hydraulic valves and pump motor that are controlled electrically by the EBCM. The BPMV uses a 4 circuit configuration with a front/rear split. The BPMV directs fluid from the reservoir of the master cylinder to the front wheels and fluid from the other reservoir to the rear wheels. The circuits are hydraulically isolated so that a leak or malfunction in one circuit will allow continued braking ability on the other".

You can operate the car with the EBCM removed as the interaction between the BPMV and the EBCM is electrical.

I guess the answer to your question is that, as the BPMV is "wet", it's possible that it could leak. What I don't know is where the seals are that might leak but I can't see how they could be on the face which mates with the EBCM.

Here's a picture of the 2 components. Numbers 9 and 10 are the BPMV Solenoid Valves and the EBCM Solenoid Valve Coils



(1) Electronic Brake Control Module (EBCM)
(2) EBCM Electrical Connector
(3) EBCM to Brake Pressure Modulator Valve (BPMV) Screw
(4) BPMV Electrical Connector
(5) BPMV Pump Motor
(6) BPMV Bracket Bolts
(7) Rubber Isolator
(8) BPMV
(9) BPMV Solenoid Valves
(10) EBCM Solenoid Valve Coils

DeeGee

The BPMV contains the following components:

Pump Motor
Inlet Valves (one per wheel)
Outlet Valves (one per wheel)
Master Cylinder Isolation Valves (one per drive wheel)
Prime Valves (one per drive wheel)

FWIW this is how the hyd fluid moves around the circuits



(1) Master Cylinder
(2) Master Cylinder Reservoir
(3) Pump
(4) Rear Master Cylinder Isolation Valve
(5) Rear Prime Valve
(6) Brake Pressure Modulator Valve (BPMV)
(7) Damper
(8) Right Rear Inlet Valve
(9) Accumulator
(10) Right Rear Brake
(11) Right Rear Outlet Valve
(12) Left Rear Outlet Valve
(13) Left Rear Brake
(14) Left Rear Inlet Valve
(15) Left Front Inlet Valve
(16) Left Front Brake
(17) Left Front Outlet Valve
(18) Right Front Brake
(19) Right Front Outlet Valve
(20) Accumulator
(21) Right Front Inlet Valve
(22) Damper
(23) Front Master Cylinder Isolation Valve
(24) Front Prime Valve

4 KRUSIN

Just a thought, but check your HVAC overflow tube. Mine got plugged by a spiders nest causing the water to back up in the HVAC system. It finally leaked out onto the ECBM, ultimately causing it to fail.

An easy check for this is to run your AC and make sure there is water dripping out onto the ground from the tube. If there's not, don't run your AC until it is fixed. Usually, just cutting an inch or so off the tube will fix it.

02koolC5

First welcome to the forum Second the A/C unit or anything about it is no where close to your EBCM so not sure what the other guy is talking about....


Please read this thread http://forums.corvetteforum.com/c5-t...r-fleabay.html it will tell you how to pull codes, can you see fluid? I'll bet you have code 1214 a very common problem for us C5 owners I had the same symptom you described, except for the fluid diagnosis, and can be fixed your self...any how once you pull codes be sure and post them here and get some help...honestly I don't know about the fluid leak or if its possible ...Here is another great must have thread....Thanks to the great people on this forum has saved us a ton of cash http://forums.corvetteforum.com/c5-t...l-in-here.html

good luck hope this helps

DeeGee

Great link. Just a thought but C1214 is an electronic issue with the EBCM. In this scenario it would be the result of a leak not the cause. If a leak caused a problem it would need to be fixed first.

That said, you're absolutely correct. It could be the dealer is guessing. I'm still sceptical about their diagnosis. The active handling system is complex and the only way to decide which component is at fault is to post the codes. What's certain is I wouldn't let them do what will be a really expensive job without finding out more details. It might be as simple as a clean up and a $150 fix with absfixer.com. A new EBCM is $1300+

For the OP, when you post the codes, any chance of a picture showing the leak?

KevinB03

Wow, seems one has to be a speed reader/writer to catch all the codes.
The codes are:
10 PCM P0442H
28 TCS C1214 H C
60 IPC B0516H
A0-LDCM B2282H
A0-LDCM B2284H
A0-LDCM U1064H
A1-RDCM B2283H
A1-RDCM B2285H
A1-RDCM U1064H

I didn't see any signs of fluid near the EBCM, just going by what the mechanic at the dealer told me.
Any assistance is appreciated.
Cheers,
Kevin

Tenacfan

Not sure if this applies to u or not, anywho, my AC backed up water and it leaked into passenger compartment. All kinds of crazy codes to include the dreaded CLB. Thanks to 8vette7 was able to trace it to a $20.00 relay. Replaced it and all has been good for almost a year now. And yes I now carry a spare relay in the car.

02koolC5

ok now clear all codes...and see what comes back on
the only "current" code I see is 1214 which can mean a bad relay in the unit and can be repaired for very cheap...gotta read that thread I gave you , its how I fixed mine....Its not leaking if you don't see any signs don't let that guy near it!!

DeeGee

Looks like a bad EBCM. C1214C is the classic fault code.

Looks like a DIY fix if you're feeling brave or ship it to absfixer.com and they'll fix it for about $150.

It's easy to remove the EBCM. When you're in there take a look for any leaks. You can run the car while its away for repair but obviously, you'll lose AH/TCS/ABS until its replaced.

Looks like you just avoided a $2000 invoice from the dealer

DeeGee

Electronic Brake Control Module (EBCM) Replacement
Removal Procedure

Turn the ignition switch to the OFF position.
Disconnect the EBCM harness connector.
Remove the two insulator nuts (1).
Lift the EBCM/BPMV out of the bracket high enough to allow clearance to remove the insulator mounting bolt and the EBCM.
Remove the insulator mounting bolt from the EBCM.
Remove the six EBCM to BPMV bolts.
Separate the EBCM from the BPMV by gently pulling apart until separated.
Carefully remove the seal.
The seal may by reused if it is not cut or damaged.

Installation Procedure

Clean the BPMV seal surface with alcohol using a clean rag.
Install the seal to the BPMV if it is not cut or damaged.
Install the EBCM to the BPMV.
Notice

Refer to Fastener Notice in Cautions and Notices.
Tighten the six mounting bolts in the following sequence:
Tighten
First pass to 3 N·m (27 lb in).
Second pass to 6 N·m (53 lb in).

Important

If the insulator nut was removed it must be replaced with a new insulator nut.

Install the front EBCM insulator mounting bolt.
Tighten

Tighten the bolt to 14 N·m (10 lb ft).
Install the EBCM/BPMV into the bracket.
Install the two insulator nuts (1).
Tighten

Tighten the two insulator nuts to 12 N·m (106 lb in).
Connect the EBCM harness connector.

Important

Both sides of the EBCM harness connector must be engaged with lever before closing.

Turn the ignition switch to the ON position; do NOT start the engine.
Perform the Diagnostic System Check - ABS .

KevinB03

Thanks so much for the guidance. I cleared all the codes and still get the 28 TCS C1214 H C code. I'll remove the EBCM and look to see if there is any sign of fluid and send the unit to be rebuilt.
Cheers,
Kevin