Can the brake system be bled if the EBCM does not work?

[JamesLond]

I attempted to fix my module, but it was unsuccessful. Fortunately, I'm not concerned about having ABS.

However, I have a problem that I didn't consider before starting my brake line job. I've already replaced a couple brake lines that connect to the ABS valve and I still have some more to go.

Considering the system was opened directly at the ports on the valve, I don't know how I can force the solenoids to actuate once I get everything back together.

So I guess I need to know if I absolutely have to get a working EBCM installed before the car can be driven. Or will I have to sort of bypass this valve?

 

[Scottydoggs]

pretty sure you need a higher end scanner to bleed the abs.

 

[rockola1971]

It can be done but it is a total pain in the **** and takes forever! You bleed like normal and then take your yukon down your drive or road near your home and lock up the brakes to force the ABS on which will open the solenoids and let air pass toward the wheels. Then bleed again and keep doing this until there is a firm brake pedal. Its easier to do on rocks, grass, dirt vs a road. But if your ABS system does not work or control to your ABS pump does not work then the solenoids will not be actuated and the previous procedure is useless to you.
What sort of ABS problem are you chasing and what all have you done?

 

[JamesLond]

It can be done but it is a total pain in the **** and takes forever! You bleed like normal and then take your yukon down your drive or road near your home and lock up the brakes to force the ABS on which will open the solenoids and let air pass toward the wheels. Then bleed again and keep doing this until there is a firm brake pedal. Its easier to do on rocks, grass, dirt vs a road. But if your ABS system does not work or control to your ABS pump does not work then the solenoids will not be actuated and the previous procedure is useless to you.
What sort of ABS problem are you chasing and what all have you done?

The description of the problem I was encountering is in this thread.

Several ABS codes

When you first start the car up, there's nothing, but after a minute or two of driving, the abs light comes on. It also feels like something is dragging. My scantool pulled these codes: C0265 C0245 C0241 C0251 C0246 C0242 C0252 There's so many I don't know where to begin. I kind...

www.tahoeyukonforum.com

I cleaned up the ground on the frame rail close to the front driver side rail good. After I saw no change there, I tried to confirm there was power and ground being delivered to the EBCM by connecting a test light at the harness electrical connector ground and power pins.

Once I found power and ground were there, I pulled the EBCM and added fresh solder to the connections that looked bad.

 

[JamesLond]

It can be done but it is a total pain in the **** and takes forever! You bleed like normal and then take your yukon down your drive or road near your home and lock up the brakes to force the ABS on which will open the solenoids and let air pass toward the wheels. Then bleed again and keep doing this until there is a firm brake pedal. Its easier to do on rocks, grass, dirt vs a road. But if your ABS system does not work or control to your ABS pump does not work then the solenoids will not be actuated and the previous procedure is useless to you.
What sort of ABS problem are you chasing and what all have you done?

The description of the problem I was encountering is in this thread.

Several ABS codes

When you first start the car up, there's nothing, but after a minute or two of driving, the abs light comes on. It also feels like something is dragging. My scantool pulled these codes: C0265 C0245 C0241 C0251 C0246 C0242 C0252 There's so many I don't know where to begin. I kind...

www.tahoeyukonforum.com

I cleaned up the ground on the frame rail close to the front driver side rail good. After I saw no change there, I tried to confirm there was power and ground being delivered to the EBCM by connecting a test light at the harness electrical connector ground and power pins.

Once I found power and ground were there, I pulled the EBCM and added fresh solder to the connections that looked bad, slapped it back together with some RTV and reinstalled it.

Everyone asks about how to manage when the ABS module works, but I've never seen anyone ask if your screwed if it doesn't work period.

 

[rockola1971]

I would reflow ALL solder joints in EBCM and also ohm out all soilenoids to verify they are all good. It may also be time to get the Yukon on a TECH II but that will be fun with no brakes. Id atleast run the automated bleed from a tech II and see what happens.

 

[MassHoe04]

I would reflow ALL solder joints in EBCM and also ohm out all soilenoids to verify they are all good. It may also be time to get the Yukon on a TECH II but that will be fun with no brakes. Id atleast run the automated bleed from a tech II and see what happens.

When you have time...

Could you explain the process of how to "Ohm out" something? I know basics about volts, amps and resistance. But could use a lesson on the process you mention and what we might be looking for. I have used a multi-meter to check for voltage, but I have no idea where to put probes to check things like solenoids or what to look for to know something is good or bad. How would we ohm out a solenoid (ABS or any other solenoid)? Thanks!

 

[rockola1971]

When you have time...

Could you explain the process of how to "Ohm out" something? I know basics about volts, amps and resistance. But could use a lesson on the process you mention and what we might be looking for. I have used a multi-meter to check for voltage, but I have no idea where to put probes to check things like solenoids or what to look for to know something is good or bad. How would we ohm out a solenoid (ABS or any other solenoid)? Thanks!

"Ohming" something out is checking the resistance of a wire, electrical device, component, etc. A solenoid is a coil of wire and a mechanical valve that is drawn closed or open by the magnetic field of the coil when it is energized. A coil has a general designed in the system value to provide a certain amount of magnetism when energized. You take a multimeter and set it on resistance. Checking resistance it doesnt which lead of the meter goes where (red and black). You will touch one lead to one side of the coil and the other lead to the other side. In this case the 2 "sides" of the coil come down to the electrical connector and that is where you connect your meter to check resistance. All the solenoid coils in the EBCM will likely be near the same values. A zero value as measured will mean the coil (its coil of wire) has essentially melted together and its resistance lowered and is now drawing too much current (Not designed into the circuit by the engineers). This is what can cause connectors to get too hot and melt and even wires melting down and fuses start to pop. GM unfortunately does not list in schematics the resistance values but most of the Helm Manuals (GM Factory service manuals) will have the values. Let me dig up a schematic for your EBCM and I will list points for each solenoid to check. Ill add schematic here. Does your Tahoe have traction assist or no? (2 different schematics)

 

[MassHoe04]

"Ohming" something out is checking the resistance of a wire, electrical device, component, etc. A solenoid is a coil of wire and a mechanical valve that is drawn closed or open by the magnetic field of the coil when it is energized. A coil has a general designed in the system value to provide a certain amount of magnetism when energized. You take a multimeter and set it on resistance. Checking resistance it doesnt which lead of the meter goes where (red and black). You will touch one lead to one side of the coil and the other lead to the other side. In this case the 2 "sides" of the coil come down to the electrical connector and that is where you connect your meter to check resistance. All the solenoid coils in the EBCM will likely be near the same values. A zero value as measured will mean the coil (its coil of wire) has essentially melted together and its resistance lowered and is now drawing too much current (Not designed into the circuit by the engineers). This is what can cause connectors to get too hot and melt and even wires melting down and fuses start to pop. GM unfortunately does not list in schematics the resistance values but most of the Helm Manuals (GM Factory service manuals) will have the values. Let me dig up a schematic for your EBCM and I will list points for each solenoid to check. Ill add schematic here. Does your Tahoe have traction assist or no? (2 different schematics)

Thanks! I am not currently having a problem with any solenoids. I wanted to understand the whats and hows on checking these. In case I need to in the future.
Mainly, I thought your expert electrical diagnostic abilities might help explain the testing you were mentioning to @JamesLond, helping him diagnose his issue.

I don't want to take too much of your time away from you. I was just looking to learn a little along the way...