Mace

I have read and read about this for several weeks as I knew I was going to buy a car with this issue, and the issue is intermittent.
The car belonged to my in laws who have ran into problems because of health problems.
I have replaced the battery as the car had to be jumped several times over the past.
The car has set for some time but the the problem was there before it set.

I forgot to add I am getting the 1226,1233 and 1255. I also read Bills sticky on the connectors which I plan on looking at, along with flushing the brake fluid.

I also looked at the sticky for the retro fit for the 99-00 from the 01-04 ecbm, and I will assume it doesn't work for the 97-98. So with all this being said..well written..the question is , is there a fix for the 98?

Thanks
mace

jcgunn

In short, no. Used units sell for over $1000 on that auction site and they are...used.

coia96vette

I believe the '97 and '98 EBCM was located in the back by the differential. That was changed to the engine bay in the later years. Since they are no longer available new you have only two choices. Either live with it or try to find a used one that still works. They are getting very hard to find and very expensive when you do find one.

coia96vette

Thanks for the correction 8vette7. I forgot that the AH came out mid year in '98.

Mace

If this thing is int he front where do i find it
thanks
mace

Mace

Well I'm screwed..it's on the diff...as Daffy said,,shoot me now..shoot me now
mace

Mace

Even with the codes is it possible it could be a connection or a broken wire to a wheel sensor or a hub??

Thanks
mace

earlyseventy6

I was watching "Wheeler Dealers" and they have a shop / factory that specifically rebuilds these units in the EU. Tested solenoids , electric pumps, and repaired if necessary. Now the one that was being rebuilt for the show was a VW VR6 . which a new unit would cost over 2000.00. They explained there were several sections across the shop that rebuilt different makes and models from the 80`s and 90`s. wondering if there is something like that going on here in the US.

Mace

Heck I'd send it to the EU if they could fix the problem

Mace

Well we watched the video for wheeler dealers and found the the vr6 video. It's bba reman, so I emailed them and asked the question. Also there is a site here in the US and will call them tomorrow.
Wish me luck

mace

sirdano

Following since I have a AH 98.

Mace

Sorry..I've been helping with my inlaws and I'm on this stupid hot project. I'll go look again but it's raining like mad here

Bill Dearborn

The RF Wheel Speed Sensor codes are telling us that it is seeing unexpected variations in the wheel speed. That could be because of a bad hub (on a 19 year old car a hub could definitely be loose, so that needs to be checked), bad wiring/connections, supply voltage to the EBCM or ground connection of the EBTCM. The 1255 code is an issue if it is a C1255. That code can be caused by EBTCM voltage or ground connection issues or a failed EBTCM. There is no fix if the EBTCM does actually have an internal failure. U1255 is about the same. It means there has been a communication failure. Voltage and Ground connections can affect this also but if it isn't a voltage or ground issue or an issue with the data link then the EBTCM needs to be replaced as well.

Now to throw another clinker into the mix. There were two levels of EBTCMs for the rear system. The 97s and some 98s were delivered with a design problem and had trouble tracking wheel speeds properly. They would set the C1226 or C1233 or similar codes due to losing a lock on the wheel speed signal frequency. Some time in late 97 or early 98 Delphi redesigned the unit to cure the problem. The redesigned unit with a new part number hit the GM Repair Parts Inventory some time in the last half of 99. I had been having this problem with my 97 and had the EBTCM replaced under warranty as soon as the redesigned part was available. I just tried to look up the part number for the redesigned unit but in the close to 18 years since I was involved in this it has disappeared from my data base.

Hope an pray cleaning all of the electrical connections resolves your problem. It is likely if the car is stock that the EBTCM was never swapped for the redesigned unit. The failure usually only occurred on cars that were being autocrossed and the ABS would fail in the middle of a run resulting in a fair number of flat spotted tires.

Bill

lionelhutz

You likely could still upgrade to the newer unit, but you'd have to also make your own bracket.

The SWPS for the 01+ systems has 2 less wires then the 00- systems. The yaw and accelerometer each require an extra wire. So, the necessary wires are available to use for retrofitting these sensors.

As for repairing. The EBTCM modules that fail due to the main control circuit board failing are essentially not repairable, simply due to the way the board is made and installed into the module. If the module is not responsive to diagnostic code checks and you've double checked all the wiring then the module is garbage. Lots of people have paid various repair companies to attempt to fix them with no luck.

Bill Curlee

Great information!

The EBTCM as well as all the other C5 electrical modules are extremely sensitive to improper electrical voltages. Before you get too wrapped up in module failure, you need to make sure that you:

- Have a proper battery in 100% working order
- Power to the module needs to be measured with a DC Volt meter at the supply fuses to be sure that you have FULL Battery voltage at that fuse.
- Module Grounds need to be verified clean and tight and have minimal resistance to chassis ground.

Battery Chassis ground wire G-104/108 needs to be cleaned and minimal resistance to chassis ground.


Once ALL of that is in proper order, Clear ALL the DTCs and see if you still have issues with 1255. Like 8vette7 stated, you need to determine if it a C or U prefix. The "C" could be module Power and or Ground related.

As 8VETTE7 stated, the female pins are prone to spreading and will cause 1226,1233 DTC C1221-C1235 Wheel Speed Sensor Circuit

NOTE! The EBTCM DTCs need to be pulled and read WITH OUT turning the ignition switch to OFF and back on. The EBTCM runs a start up process check and some DTCs that pop in that ignition cycle are cleared when you turn the ignition OFF and them ON.


New connector on the LEFT,,, BAD pins on the right!!

Mace

The clouds have finally parted and the weather cleared. I went and it is a C code.
Also,that ou for the great info. When I get a free moment I plan to start cleaning connections.
Thank you all again

mace

RedRiderZR1

If all the above does not work and it is the module than your options are a good used one ($$$) or living with it. But there is a possibility yours can be repaired if it is the PC board on the EBCM and not the logic board. I took mine apart and found 2 bad ceramic capacitors on the board. So there is a possibility it can be fixed. Hopefully your looking at power/ground issues.

Mace

Thanks for the replies.
The first thing I did was replace the battery as it was almost 5 years old and they had to jump it to start it.
I'm getting tires on it today and asked them to look at the right front hub assembly while the wheel is off.
Like I said, I am trying to get this thing road worthy, there are cob webs under it it sat so long.
BUt something weird today, while running to get tires put on no abs/tcs lights...what do you think.
Thanks again
mace

Mace

well it look like a bad hub to start with , let me get that on and I'll post from there.
1 favor, when I began looking at this I found a youtube video on how to clear the codes, if someome could point me to that I's appreciate it .

Thanks
mace

Mace

Thank you sir..will post the results as soon as the hub is replaced//stay tuned..same bat time same bat channel

mace