I just got my Innovas 3160 scan tool, hopefully I can finally kill the abs light.

It found 8 ABS codesCO225,CO226,CO227,CO242,CO246,CO251,CO252 AND CO265.

I have not found what all of the codes mean yet but it might be the ABS computor as sujested here. I have a 2001 4x4 Blazer and have already been directed to the thread about that year having lots of ABS computer problems.

If you know these codes your help will be greatly appreciated.

I cleared the codes and CO225 keeps coming back even though I haven't driven the Blazer yet

Thank you
Blazeme

 

C0225 - Left Front Wheel Speed Sensor Circuit Open
C0226 - Left Front Wheel Speed Signal Missing
C0227 - Left Front Wheel Speed Signal Erratic
C0242, C0246, C0251, & C0252 - EBCM Control Valve Circuit
C0265/C0266 - EBCM Motor Relay Circuit

I would start by inspecting the wiring to the left wheel speed sensor and disconnecting, cleaning, and then reconnecting the electrical connection to the EBCM.

 

Thanks
This all started after I changed both front wheel hubs over 1 year ago. I used after market hubs and had no Abs light till then. After the light came on I tested both speed sensors and had the correct signal out of both.

We drove it like that till one day we had a pedal that went most of the way to the floor and there was a hissing sound like the power booster was leaking. I read up and found that the wheel sensors could cause this. At that time I reinstalled and tested the original GM sensors in the front replacement hubs. This stopped the soft pedal and hissing noise and they never returned. However the ABS light is still on. Also the brake light comes and goes.

At one point last fall I replaced the front drivers side caliper as the Blazer seams to pull to the left. It made no difference.

Looks like I will be rechecking the wheel speed sensor as suggested. It is the code that came right back after clearing them, could be the wires are broken as it is the original sensor.

Thanks for your help swartlkk And thanks for your work posting DTCs it is great help to all.

Blazeme

 

OK I made out to the garage and tested the resistance of both the front wheel sensors.

Right side - 1,001 ohms

Left side - no continuity

I will replaced the bad left sensor and try to check the connections at the EBCM. I need to do and axle and seal on the left side also. Can't wait

Any wiring schematics and diagnostics info available to help me understand which wire might have the bad connections that are causing my other codes?

Blazeme

 

If the front brake is dragging it might be the brake hose. Jack it up and apply the brake. Then see if the wheel turns freely. If not loosen the bleed screw and if the brake stops dragging the hose has colapsed inside and is acting like a check valve.

 

I did this test about a month ago and opening the bleeder made no differance.
I had that happen on a 1977 full size Chevy pickup. It was the steel bracket that held the brake hose on the A arm. It had rusted and was pinching the hose shut. Only found the problem after I replaced everything else.

Blazeme

 

Last night I replaced the left front axle, axle seal and wheel speed sensor. Inner CV was worn and seal was leaking.

I then cleared all of the ABS codes. After driving the Blazer I set the following codes again.Co225,Co226,Co227. All codes for the left front speed sensor.

I did notice that the end of the Gm speed sensor I had installed in my after market hub was worn off on the end. It had been hitting on the teeth of the hub. Now I may have enough wear in the teeth to cause to much clearance. Or a bad connection In the wiring.

Can someone refresh me on the test to check output from the sensor. If I remember right it Milli-amps or Milli-volts and should test around 350 when the wheel is spinning.

Thanks
Blazeme

Update
I found out the signal from the speed sensor is measured in Milli-volts ac I was testing Milli-volts dc.
The sensor I installed last night I thought was one that came in the after market hub assembly, Turns out it was one of the original Gm sensors and so was the one I removed last night. Both of the GM sensors were to long and hit on the teeth of the hub.The one I Installed last night was already destroyed from hitting after only a few miles. I found the after market sensor that came in the replacement hub and it fit in without hitting.

I cleared the codes and drove the Blazer And code CO227(erratic signal left front sensor)is the only one that came back now. I will check the Milli-volt out put on both wheels and see if the are similar. Then I will have to check for loose connections and inspect the teeth on the hub. I know the teeth are worn down some from hitting the Gm sensor, this might be what is setting code CO227 or a tooth could be broken.

Next I checked the left front sensor output and had 300 Milli-volts, about the same as the right front sensor. I then cleaned some debris from the teeth in the hub. None of this made any difference as I still set Code CO227 Also Code CO265 ( low volts EBCM motor circuit) came back.

At this point I decided the hub was trashed and replace it. This cured the CO227 code and the only one left was CO265..

Now I removed the air filter box and cleaned the grounds on the radiator support. Cleared codes and CO265 came back.

I then removed the connector for the main power to the EBCM and tested 12.5 volts Battery voltage and saw no problems with the connections. Reconnected the plug, cleared the codes and CO265 set again. Removed all the plugs to the EBCM and the ECBM from the solenoid body. I found no sure bad connections and then reinstalled the EBCM. Another code clearing and drove the Blazer About 5 miles and no codes were set.

I am not confident that the CO265 code is done. I may yet need the ECBM rebuilt, time will tell.

Blazeme

 

it sounds like wiring or connection problem

 

In the last 2 weeks the ABS light has been on part of the time and off most of the time. It has only set code Co265 and no others. It came on almost every time it was wet outside. Only once when it was dry.

This leads me to think I need to find and clean the other one or two grounds I have read about on the form.So far I have only cleaned the ground on the radiator support.

If that doses not cure it must be the ECBM itself.

Blazeme

 

i would definatly consider the abs relay,contacts and wiring also abs system ground