ABS Problems! What do you guys think?

[2002_z28_six_speed]

I have never been able to get my ABS to work. I have actually traced every single wire and found the system to be wired correctly.

The ABS module never worked. I finally bought EFILive and found out that it was throwing the code Bad Pump Motor. C0110 or something like that. (from memory)

Makes sense never because the unit would never pulsate. I even checked the motor and open it open at the bottom connector. The BRAKE, ASB INOP, and ASR OFF lights were all on but the service vehicle light was off.

So, I recently replaced the pump with a used unit. The system still doesn't work but the situtation has changed. The unit doesn't throw a bad pump code anymore. It throws these!!

http://forum.efilive.com/attachment.php?attachmentid=1198&stc=1&d=1168398220

Now it looks like the pump doesn't have a problem but the communication is all messed up. The service vehicle light is now on where before it was off.

I just don't get it.

What I am now thinking is that the replacement module is not responding to the other modules after the VIN is broadcasted. OR the module has some problem making it unusable.

This is really frusterating because I have one module that is communcating on the network but the pump doesn't work and one module where I guess the pump is working but I am getting those communication problems.

Suggestions? I wish I could combine the two modules... electronics from one and the pump from the other.

PS. I did search but haven't found exactly the right answer.

I was hoping someone could tell me that you can't use a previously used part, or it just needs to relearn.... or something like that.

[Tordne]

I had a fault with the traction control in my vehicle some time ago and they changed the TC/ABS computer (or at least that's what they told me).

Does your car have TC, and does it work?

[2002_z28_six_speed]

My car does have the 4 channel ABS module and wiring for ASR.

I have never been able to get it to work though. The car was wrecked. Fixed most of the problems since ownership but not this one.

Also, a new Bosch pump from the dealer is 800.00 USD.

[TAQuickness]

Welcome to the forum 2002_z28_six_speed.

I've had the same codes in the past and it turned out to be a bad ground on the left rear cylinder head. Double check all your grounds again, and all the wiring harness that may have been disturbed during the pump swap.

With the engine running, if you use the scan tool and clear all DTC's, do those two come right back?

[2002_z28_six_speed]

They come back as soon as they are cleared.

I could see a bad ground being the problem. At first, I thought it was just a config issue because if it lost com I thought the com signal was ok. I see what you are saying will try this first thing in the morning.

I felt the brake pedal modulate one time while going down the road. However, I have yet to get it to repeat this again.

[TAQuickness]

Let us know how it goes after you check the grounds. Took me a while to (a month or so) before I found my bad ground. I just kept looking in the wrong spots.

Also, any chance you have access to a spare module? One you could swap out for a few minutes just to see if your module is the problem?

[PladdPezzPunk]

usually in my cases, when i see a code like this, if you bleed the brakes properly and run the test function on the abs system(that will bleed the air out of the abs unit) you will wind up replaceing the abs module/pump assembly. If you give me the Year, Make and Model, i can post up the factory Diagnostic sequence along with wiring diagrams for you.:)

[PladdPezzPunk]

OK, since I'm an idiot and can't read your name, i already have the YMM so here is the diag. sequence and bleed sequence for your car. hope this helps.

DTC C0110



http://www.silveradoss.com/gallery/displayimage.php?pos=-836



Circuit Description
The pump motor is an integral part of the BPMV, while the pump motor relay is integral to the EBCM. The pump motor relay is not engaged during normal system operation. When ABS or TCS operation is required the EBCM activates the pump motor relay and battery power is provided to the pump motor.

Conditions for Running the DTC


The ignition switch is in the ON position.
Initialization is complete.
Conditions for Setting the DTC


Pump motor voltage is not present 60 milliseconds after activation of the pump motor relay.
Pump motor voltage is present for more than 2.5 seconds with no activation of the pump motor relay.
Pump motor voltage is not present for 40 milliseconds after the pump motor relay is commanded off.
Action Taken When the DTC Sets
If equipped, the following actions occur:


A malfunction DTC stores.
The ABS/TCS disables.
The amber ABS/TCS indicator(s) turn on.
The Brake Warning indicator turns on.
Conditions for Clearing the DTC


The condition for the DTC is no longer present and you used the scan tool Clear DTC function.
The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids


It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
Thoroughly inspect any circuitry that may be causing the complaint for the following conditions:
Backed out terminals
Improper mating
Broken locks
Improperly formed or damaged terminals
Poor terminal-to-wiring connections
Physical damage to the wiring harness
The following conditions may cause an intermittent malfunction:
A poor connection
Rubbed-through wire insulation
A broken wire inside the insulation
If an intermittent malfunction exists refer to Testing for Intermittent and Poor Connections.
Test Description
The number below refers to the step number on the diagnostic table.


Tests the pump motor circuits of the BPMV for a short to the housing of the BPMV. The wiring from the BPMV to the EBCM should not be repaired.

[PladdPezzPunk]

and this is the bleed sequence for your car.

ABS Automated Bleed Procedure

Bleeding the ABS System
Perform a manual or pressure bleeding procedure. If the desired brake pedal height results are not achieved, perform the automated bleed procedure below.
The procedure cycles the system valves and runs the pump in order to purge the air from the secondary circuits normally closed off during normal base brake operation and bleeding. The automated bleed procedure is recommended when air ingestion is suspected in the secondary circuits, or when the BPMV has been replaced.

Automated Bleed Procedure

Notice: The Auto Bleed Procedure may be terminated at any time, during the process by pressing the EXIT button. No further Scan Tool prompts pertaining to the Auto Bleed procedure will be given. After exiting the bleed procedure, relieve bleed pressure and disconnect bleed equipment per manufacturers instructions. Failure to properly relieve pressure may result in spilled brake fluid causing damage to components and painted surfaces.



Raise the vehicle on a suitable support. Refer to Vehicle Lifting.
Remove all four tire and wheel assemblies.
Inspect the brake system for leaks and visual damage. Repair or replace as needed.
Inspect the battery state of charge.
Install a scan tool.
Turn ON the ignition, with the engine OFF.
With the scan tool, establish communications with the EBCM. Select Special Functions. Select Automated Bleed from the Special Functions menu.
Bleed the base brake system.
Follow the scan tool directions until the desired brake pedal height is achieved.
If the bleed procedure is aborted, a malfunction exists. Perform the following steps before resuming the bleed procedure:
If a DTC is detected, refer to Diagnostic Trouble Code (DTC) List and diagnose the appropriate DTC.
If the brake pedal feels spongy, perform the conventional brake bleed procedure again.
When the desired pedal height is achieved, press the brake pedal in order to inspect for firmness.
Remove the scan tool.
Install the tire and wheel assemblies.
Inspect the brake fluid level.
Road test the vehicle while inspecting that the pedal remains high and firm.


And conventional pressure bleed...................

Hydraulic Brake System Bleeding (Manual)

Notice: When adding fluid to the brake master cylinder reservoir, use only Delco Supreme 11, GM U.S. P/N 12377967, GM Canada P/N 992667, or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.

Notice: Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Service Precautions.



Place a clean shop cloth beneath the brake master cylinder to prevent brake fluid spills.
With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake pedal effort increases significantly, in order to deplete the brake booster power reserve.
If you have performed a brake master cylinder bench bleeding on this vehicle, or if you disconnected the brake pipes from the master cylinder, you must perform the following steps:
3.1. Ensure that the brake master cylinder reservoir is full to the maximum-fill level. If necessary, add Delco Supreme 11, GM U.S. P/N 12377967, GM Canada P/N 992667, or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
If removal of the reservoir cap and diaphragm is necessary, clean the outside of the reservoir on and around the cap prior to removal.
3.2. With the rear brake pipe installed securely to the master cylinder, loosen and separate the front brake pipe from the front port of the brake master cylinder.
3.3. Allow a small amount of brake fluid to gravity bleed from the open port of the master cylinder.
3.4. Reconnect the brake pipe to the master cylinder port and tighten securely.
3.5. Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal.
3.6. Loosen the same brake pipe to purge air from the open port of the master cylinder.
3.7. Tighten the brake pipe, then have the assistant slowly release the brake pedal.
3.8. Wait 15 seconds, then repeat steps 3.3-3.7 until all air is purged from the same port of the master cylinder.
3.9. With the front brake pipe installed securely to the master cylinder - after all air has been purged from the front port of the master cylinder - loosen and separate the rear brake pipe from the master cylinder, then repeat steps 3.3-3.8.
3.10. After completing the final master cylinder port bleeding procedure, ensure that both of the brake pipe-to-master cylinder fittings are properly tightened.

Fill the brake master cylinder reservoir with Delco Supreme 11, GM U.S. P/N 12377967, GM Canada P/N 992667, or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. Ensure that the brake master cylinder reservoir remains at least half-full during this bleeding procedure. Add fluid as needed to maintain the proper level. Clean the outside of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm.
Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic circuit bleeder valve.
Install a transparent hose over the end of the bleeder valve.
Submerge the open end of the transparent hose into a transparent container partially filled with Delco Supreme 11, G M U.S. P/N 12377967, GM Canada P/N 992667, or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal.
Loosen the bleeder valve to purge air from the wheel hydraulic circuit.
Tighten the bleeder valve, then have the assistant slowly release the brake pedal.
Wait 15 seconds, then repeat steps 8-10 until all air is purged from the same wheel hydraulic circuit.
With the right rear wheel hydraulic circuit bleeder valve tightened securely - after all air has been purged from the right rear hydraulic circuit - install a proper box-end wrench onto the LEFT REAR, without traction control, or the LEFT FRONT, with traction control, wheel hydraulic circuit bleeder valve.
Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.
With the left rear, without traction control, or the left front, with traction control, wheel hydraulic circuit bleeder valve tightened securely - after all air has been purged from the left rear, without traction control, or the left front, with traction control, hydraulic circuit - install a proper box-end wrench onto the RIGHT FRONT, without traction control, or the LEFT REAR, with traction control, wheel hydraulic circuit bleeder valve.
Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.
With the right front, without traction control, or the left rear, with traction control, wheel hydraulic circuit bleeder valve tightened securely - after all air has been purged from the right front, without traction control, or the left rear, with traction control, hydraulic circuit - install a proper box-end wrench onto the LEFT FRONT, without traction control, or the RIGHT FRONT, with traction control, wheel hydraulic circuit bleeder valve.
Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.
After completing the final wheel hydraulic circuit bleeding procedure, ensure that each of the 4 wheel hydraulic circuit bleeder valves are properly tightened.
Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme 11, GM U.S. P/N 12377967, GM Canada P/N 992667, or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
Slowly depress and release the brake pedal. Observe the feel of the brake pedal.
If the brake pedal feels spongy, repeat the bleeding procedure again. If the brake pedal still feels spongy after repeating the bleeding procedure, perform the following steps:
21.1. Inspect the brake system for external leaks.
21.2. Pressure bleed the hydraulic brake system in order to purge any air that may still be trapped in the system.

Turn the ignition key ON, with the engine OFF. Check to see if the brake system warning lamp remains illuminated. Important: DO NOT allow the vehicle to be driven until it is diagnosed and repaired.
If the brake system warning lamp remains illuminated, refer to Symptoms - Hydraulic Brakes. See: Hydraulic System\Testing and Inspection\Diagnosis By Symptom (Hydraulic Brakes)\Symptoms- Hydraulic Brakes


Sorry for the long post but hope this helps

[2002_z28_six_speed]

I could see air causing a pump code.

The only thing is that when I put a digital multimeter acrost the terminals it read open or inifinity resistance. Is that how the pumps on your guys cars read? That is why I took that pump out.

[PladdPezzPunk]

i would agree, you should see a resistance.

[2002_z28_six_speed]

UPDATE UPDATE!!

I took apart my old module. I found out that infact the motor was burned out. Inside the casing it was rusted beyond belief with a smell I reconized as burning motors. The unit was difficult to turn and the shaft was marred horribly.

I thought about for awhile. My other module which was out of the car had good electronics and a bad pump. Took a torx driver and took apart the rest of the unit. It turns out that the eletronics, valvebody, and motor are all hermatically seperate. This means it would be easy to interchange electronics from one pump to another EVEN WHILE IT IS STILL INSTALLED ON THE CAR. Pics later. Anyways....

I put two and two together...literally. You would be surpised how easy it was to take the modules apart and combine the good parts. GO GERMAN ENGINEERS!! (and beer).

Now my U codes and pump codes are both gone.

I am left only with a Brake switch code. C0040 Brake Pedal Switch A. Trying to resolve now. I have already tried adjusting the switch as well as verifying that the switch works ok at pin 6 of the ABS module when the brake is pressed/released.


Another thing.... Why when I look up on the net does C0040 come up as a speed sensor??? I hope the program isn't leading me in the wrong direction.

[PladdPezzPunk]

nice work. glad to see it all got taken care of. i'll look up the c0040 at work tommorow.

[joecar]

Good work.

More pics please (disassembled views).

[2002_z28_six_speed]

Actually, I am going to take more pics tommorow. Maybe tonight Including of the circuit board once I get the plastic case off. I want to run all the part numbers and get the ID of what processor they used. No plans for reproduction. I just want to know.

Right now, I am debating why some of the electromagnetic valves are flat topped and why some are rounded off on the top.

I also noticed that one module had a spring type bracket around the solenoids and the other module didn't. See the pic of the module in the car. Wondering why they even included such a flimsy piece of metal anyways. Maybe it helps to keep the coils on the electronics side from wobbling around too much but the bracket just doesn't have alot of depth to it.

There is a pic of my tortured Torx driver after the experiment. It isn't throwing any more codes other than the brake switch.


I wanted to add something else. When I had the other module in my car it was very hard to start and the BRAKE light wasn't working.

[2002_z28_six_speed]

Anyone know anything about this C0040? Is it Brake Pedal A Switch of FR Wheel sensor?

[2002_z28_six_speed]

Hate to keep posting on this if it annoys you guys.


Still haven't found resolution for the DTC. The ABS actually comes on when romping on the brakes. Tonight was the first time the ABS came on in that car for 3 years. The ABS INOP and ASR OFF light are on despite the ABS working sometimes.

[TAQuickness]

ABS inop and ASR off is commonly caused by a discrepancy in the wheel sensor readings. This usually happens with upgrades to the rear end (gears, new rear, etc..).

Can you verify vehicle speed with a friendly cop or GPS? Also, have a look at all 4 corners and inspect the electrical connections at the speed sensors.

[joecar]

Anyone know anything about this C0040? Is it Brake Pedal A Switch of FR Wheel sensor?

C0035 C0040 C0045 C0050 One of the following conditions exists for 0.02 seconds:
A short to voltage - the wheel speed sensor signal circuit greater than 4.25 volts.
An open - the wheel speed sensor signal circuit voltage is greater than 4.25 volts and wheel speed sensor return circuit voltage is less than 0.75 volts.I take it each of those four codes is specific to each of the 4 wheels (I'm supposing).

[joecar]

Continuing on...


<table border="1" width="100%"> <tbody> <tr> <th align="center" valign="bottom"> Step
</th> <th align="center" valign="bottom"> Action
</th> <th align="center" valign="bottom"> Value(s)
</th> <th align="center" valign="bottom"> Yes
</th> <th align="center" valign="bottom"> No
</th></tr> <tr> <td colspan="5" align="left" valign="top"> Schematic Reference: ABS Schematics (http://forum.efilive.com/servlets/CellHandler?CellId=946&RefDoc=665621&evc=sm)
</td></tr> <tr> <td align="center" valign="center"> 1
</td> <td align="left" valign="top"> Did you perform the ABS Diagnostic System Check?
</td> <td align="center" valign="center"> --
</td> <td align="center" valign="bottom"> Go to Step 2 (http://forum.efilive.com/#S02)
</td> <td align="center" valign="bottom"> Go to Diagnostic System Check - ABS (http://forum.efilive.com/servlets/CellHandler?CellId=1363&RefDoc=665621&evc=sm)
</td></tr> <tr> <td align="center" valign="center"> 2
</td> <td align="left" valign="top">
Install a scan tool.
Turn ON the ignition.
Set up the scan tool snap shot feature to trigger for this DTC.
Drive the vehicle at a speed greater than the specified value. Does the scan tool indicate that this wheel speed DTC set?
</td> <td align="center" valign="center"> 8 km/h (5 mph)
</td> <td align="center" valign="bottom"> Go to Step 3 (http://forum.efilive.com/#S03)
</td> <td align="center" valign="bottom"> Go to Diagnostic Aids
</td></tr> <tr> <td align="center" valign="center"> 3
</td> <td align="left" valign="top">
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle (http://forum.efilive.com/servlets/CellHandler?CellId=47852&RefDoc=665621&evc=sm) in General Information.
Disconnect the wheel speed sensor connector.
Measure the resistance across the wheel speed sensor. Does the resistance measure within the specified range?
</td> <td align="center" valign="center"> 800-1600 ohms
</td> <td align="center" valign="bottom"> Go to Step 4 (http://forum.efilive.com/#S04)
</td> <td align="center" valign="bottom"> Go to Step 8 (http://forum.efilive.com/#S08)
</td></tr> <tr> <td align="center" valign="center"> 4 (http://forum.efilive.com/#TD04)
</td> <td align="left" valign="top">
Spin the wheel.
Measure the AC voltage across the wheel speed sensor. Does the AC voltage measure greater than the specified value?
</td> <td align="center" valign="center"> 100 mV
</td> <td align="center" valign="bottom"> Go to Step 5 (http://forum.efilive.com/#S05)
</td> <td align="center" valign="bottom"> Go to Step 8 (http://forum.efilive.com/#S08)
</td></tr> <tr> <td align="center" valign="center"> 5 (http://forum.efilive.com/#TD05)
</td> <td align="left" valign="top"> Inspect for poor connections at the harness connector of the wheel speed sensor. Refer to Testing for Intermittent and Poor Connections (http://forum.efilive.com/servlets/CellHandler?CellId=62112&RefDoc=665621&evc=sm) and Connector Repairs (http://forum.efilive.com/servlets/CellHandler?CellId=61973&RefDoc=665621&evc=sm) in Wiring Systems.
Did you find and correct the condition?
</td> <td align="center" valign="center"> --
</td> <td align="center" valign="bottom"> Go to Step 10 (http://forum.efilive.com/#S10)
</td> <td align="center" valign="bottom"> Go to Step 6 (http://forum.efilive.com/#S06)
</td></tr> <tr> <td align="center" valign="center"> 6
</td> <td align="left" valign="top">
Disconnect the EBCM harness connector.
Install the J 39700 (http://forum.efilive.com/servlets/RetrieveTif?pic=98818) using J 39700-530 (http://forum.efilive.com/servlets/RetrieveTif?pic=647900) to the EBCM harness connector only.
Test the wheel speed sensor circuits for the following:
An open
A short to ground
A short to voltage
Shorted together Refer to Testing for Intermittent and Poor Connections (http://forum.efilive.com/servlets/CellHandler?CellId=62112&RefDoc=665621&evc=sm) and Wiring Repairs (http://forum.efilive.com/servlets/CellHandler?CellId=61965&RefDoc=665621&evc=sm) in Wiring Systems.
Did you find and correct the condition?
</td> <td align="center" valign="center"> --
</td> <td align="center" valign="bottom"> Go to Step 10 (http://forum.efilive.com/#S10)
</td> <td align="center" valign="bottom"> Go to Step 7 (http://forum.efilive.com/#S07)
</td></tr> <tr> <td align="center" valign="center"> 7
</td> <td align="left" valign="top"> Inspect for poor connections at the harness connector for the EBCM. Refer Testing for Intermittent and Poor Connections (http://forum.efilive.com/servlets/CellHandler?CellId=62112&RefDoc=665621&evc=sm) and Connector Repairs (http://forum.efilive.com/servlets/CellHandler?CellId=61973&RefDoc=665621&evc=sm) in Wiring Systems.
Did you find and correct the condition?
</td> <td align="center" valign="center"> --
</td> <td align="center" valign="bottom"> Go to Step 10 (http://forum.efilive.com/#S10)
</td> <td align="center" valign="bottom"> Go to Step 9 (http://forum.efilive.com/#S09)
</td></tr> <tr> <td align="center" valign="center"> 8
</td> <td align="left" valign="top"> Replace the wheel speed sensor. Refer to Wheel Bearing/Hub Replacement - Front (http://forum.efilive.com/servlets/CellHandler?CellId=47747&RefDoc=665621&evc=sm) or Wheel Speed Sensor Replacement - Rear (http://forum.efilive.com/servlets/CellHandler?CellId=1416&RefDoc=665621&evc=sm) in Rear Suspension.
Did you complete the replacement?
</td> <td align="center" valign="center"> --
</td> <td align="center" valign="bottom"> Go to Step 10 (http://forum.efilive.com/#S10)
</td> <td align="center" valign="bottom"> --
</td></tr> <tr> <td align="center" valign="center"> 9
</td> <td align="left" valign="top"> Replace the EBCM. Refer to Electronic Brake Control Module (EBCM) Replacement (http://forum.efilive.com/servlets/CellHandler?CellId=954&RefDoc=665621&evc=sm) .
Did you complete the repair?
</td> <td align="center" valign="center"> --
</td> <td align="center" valign="bottom"> Go to Step 10 (http://forum.efilive.com/#S10)
</td> <td align="center" valign="bottom"> --
</td></tr> <tr> <td align="center" valign="center"> 10
</td> <td align="left" valign="top">
Use the scan tool in order to clear the DTCs.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?
</td> <td align="center" valign="center"> --
</td> <td align="center" valign="bottom"> Go to Step 2 (http://forum.efilive.com/#S02)
</td> <td align="center" valign="bottom"> System OK
</td></tr></tbody></table> <form name="bottomNavForm"> <hr> </form>

[Garry]

Hm ... all the links seem dead!?

[TAQuickness]

the links are taken from the service manuals. Unless you have them (the service manuals) installed on your PC, the links won't work.

[joecar]

Yes, sorry about the links, I copied/pasted straight from the Service Manual page...

If you need some of the links, let me know.