I hope this is the right way to go about this? New here, looking for some answers.

I have a 2003 Corvette, automatic, 35.000 miles.
Recently had a 20,000 end to end inspection with all fluids flushed, alignment, balance, etc.

I was driving the other day in traffic, at about 35 mph. The vehicle began to slow as I was coming to a stop light, and came to an abrupt stop.

The brake pedal was hard as a rock, with no play what so ever. Full pedal, to the top. All four wheels locked up. I had to have it towed, and they remained locked up till we got to the dealer ship. No Codes, No warning lights, but wont do it again for the mechanic/technican.

Suggestions, anyone experience something similar???? Please help. Stuck for an answer.
:doh:

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.
An intermittent malfunction can be caused by poor connections, broken insulation, or a wire that is broken inside the insulation.
If an intermittent malfunction exists refer to Testing for Electrical Intermittents in Wiring Systems.
Test Description
The numbers below refer to step numbers on the diagnostic table.

Step 3. Checks the resistance of the WSS.

Step 5. Checks if the WSS CKTs are shorted together.

DTC C1225 LF Wheel Speed Sensor Input is 0 Step
Action
Value(s)
Yes
No

1
Was the Diagnostic System Check performed?
--
Go to Step 2
Go to Diagnostic System Check - ABS

2
Inspect the WSS wiring and connectors for damage.
Inspect WSS for looseness or damage.
Is physical damage of sensor evident?
--
Go to Step 7
Go to Step 3

3
Disconnect the WSS at the sensor pigtail.
Using J 39200 DMM, measure the resistance between terminals A and B of the WSS.
Is the resistance within the range specified in the value(s) column?
850-1350ohms
Go to Step 4
Go to Step 7

4
With J 39200 DMM still connected, select the mV AC scale.
Spin the wheel as fast as you can by hand while monitoring the AC output.
Is the AC voltage within the range specified in the value(s) column?
Above 100 mV
Go to Step 5
Go to Step 7

5
Disconnect the EBTCM harness connector.
Install J 39700 Universal Pinout Box using the J 39700-25 cable adapter to the EBTCM harness connector only.
Using J 39200 DMM, measure resistance between terminals 15 and 31 of the J 39700 .
Is the resistance within the range specified in the value(s) column?
850-1350 ohms
Go to Step 6
Go to Step 8

6
Reconnect all connectors.
Carefully test drive vehicle above 24 Km/h (15 mph) for at least 30 seconds while monitoring a scan tool.
Does DTC reset as a current DTC?
--
Go to Step 9
Go to Diagnostic System Check - ABS

7
Replace wheel speed sensor. Refer to Wheel Hub/Speed Sensor Replacement in Front Suspension.

Is the repair complete?
--
Go to Step 10
--

8
If the resistance was low, check for short between CKTs 873 and 830. If the resistance is high, check for an open in CKTs 873 or 830. If repair of the jumper harness is needed, replace the jumper harness. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?
--
Go to Step 10
--

9
Replace EBTCM. Refer to Electronic Brake Control Module (EBCM) Replacement .

Is the replacement complete?
--
Go to Step 10
--

10
Carefully test drive vehicle above 24 Km/h (15 mph) while monitoring a scan tool for at least 30 seconds.

Does the DTC set as a current DTC?
--
Go to Step 2
Go to Diagnostic System Check - ABS

The same procedure applies for the other three wheel speed sensors. All that changes is the connector pin where you make the measurements.
Have you checked the EBCM ground G108 over by the battery? You should also check the voltage at the EBCM to see if it is at battery voltage.

Have you made any changes to the lighthing system? Changing the stop light bulbs might screw up the stop light switch signal that goes to the EBCM. This signal tells the EBCM that the brake pedal is applied.

To get the symptoms you are describing the EBCM has to think the car is still moving and one or more wheels are locked up. If one wheel speed sensor is indicating the car is moving then the EBCM will release the brakes on the other 3 wheels. Since you are getting speed variations on all 4 sensors it seems there must be a common source for the problem which may be a voltage or ground. A high resistance in the ground circuit may make the system more susceptible to radiated electrical noise that may be near you such as cell phones, etc. That may explain the randomness of the events.

Well enough said on that... Good post BLU

I think someone has the ESI maintenance DVD! :lol:

slt254 Did you mean that nothing popped up on the DIC screen or that you actually went into it and CHECKED for any codes?

Thanks for the reply and advice.....other good ideas????

correct. no codes, no warning lights. car came to complete stop, all four wheels locked up. Brake pedal hard, (full pedal) no play what so ever.

Your answer lies above

I've had a couple of cars where the ABS failed and gave the EXACT same problem you're having.

Rock hard brake until under 10mph then locks up.

Good luck.

Good post up Blu collar Z!

What is the ESI maintenance DVD?????

Do they only do that below 10 mph ? Just wondering first I'd heard of it. If not, bummer if you were going about 100+ when it happened.

What is the ESI maintenance DVD?????
It's the actual Maintenance DVD that the Dealers Mechanics use. Every now and then it will pop up on EBay, I think there are some now actually.

It ties into an OL database also, there's a bit of a learning curve with it using it but it's a great resource to have.

Here are some shots of the program, opening Screen;
http://i142.photobucket.com/albums/r117/tstar99/Repairs/d5cf5e3e.jpg

Various screen shots;

http://i142.photobucket.com/albums/r117/tstar99/Repairs/dbd02735.jpg

http://i142.photobucket.com/albums/r117/tstar99/Repairs/a7e7240f.jpg

Tim

...It ties into an OL database also, there's a bit of a learning curve with it using it but it's a great resource to have.

Tim

Looks like you have the same exact version that I have but it doesn't connect to any online database. If you look at the IP address in your first image, that IP is known as a loop-back address. It, is actually your computer. All of the data is actually on your hard drive. :thumbsup:

I knew that!!!!

:leaving:

Tim

Looks like you have the same exact version that I have but it doesn't connect to any online database. If you look at the IP address in your first image, that IP is known as a loop-back address. It, is actually your computer. All of the data is actually on your hard drive. :thumbsup:

Darn JunkMan, how many of us techies are there out here that would have known that was a loop back address! *LOL*

I knew that!!!!

:leaving:

Tim

My bad! I thought you meant online database when in your previous post! So what is a "OL" database?

My bad! I thought you meant online database when in your previous post! So what is a "OL" database?
Just a guess (On line) lol

My bad! I thought you meant online database when in your previous post! So what is a "OL" database?
I was lying... that's why I used that walking away smiley thingy! :lol:

Although being a MAN/WAN network engineer you'd think I would've noticed that huh? :rofl:

Tim

I was lying... that's why I used that walking away smiley thingy! :lol:

Although being a MAN/WAN network engineer you'd think I would've noticed that huh? :rofl:

Tim

Oh Tim! Turn in your Captain Crunch decoder ring right now! You are no longer allowed in Geekdom! :lol: :lol: :lol:

OK fine! But you are NOT getting my Danger Mouse ID card! Nope, Nada... No Way Jose!

Tim

OK fine! But you are NOT getting my Danger Mouse ID card! Nope, Nada... No Way Jose!

Tim

:rofl:

I think we are the only silly ones up this time of night!

Agreed!!!! And I'm sure that's the source of the silliness! :lol:

Tim

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.
An intermittent malfunction can be caused by poor connections, broken insulation, or a wire that is broken inside the insulation.
If an intermittent malfunction exists refer to Testing for Electrical Intermittents in Wiring Systems.
Test Description
The numbers below refer to step numbers on the diagnostic table.

Step 3. Checks the resistance of the WSS.

Step 5. Checks if the WSS CKTs are shorted together.

DTC C1225 LF Wheel Speed Sensor Input is 0 Step
Action
Value(s)
Yes
No

1
Was the Diagnostic System Check performed?
--
Go to Step 2
Go to Diagnostic System Check - ABS

2
Inspect the WSS wiring and connectors for damage.
Inspect WSS for looseness or damage.
Is physical damage of sensor evident?
--
Go to Step 7
Go to Step 3

3
Disconnect the WSS at the sensor pigtail.
Using J 39200 DMM, measure the resistance between terminals A and B of the WSS.
Is the resistance within the range specified in the value(s) column?
850-1350ohms
Go to Step 4
Go to Step 7

4
With J 39200 DMM still connected, select the mV AC scale.
Spin the wheel as fast as you can by hand while monitoring the AC output.
Is the AC voltage within the range specified in the value(s) column?
Above 100 mV
Go to Step 5
Go to Step 7

5
Disconnect the EBTCM harness connector.
Install J 39700 Universal Pinout Box using the J 39700-25 cable adapter to the EBTCM harness connector only.
Using J 39200 DMM, measure resistance between terminals 15 and 31 of the J 39700 .
Is the resistance within the range specified in the value(s) column?
850-1350 ohms
Go to Step 6
Go to Step 8

6
Reconnect all connectors.
Carefully test drive vehicle above 24 Km/h (15 mph) for at least 30 seconds while monitoring a scan tool.
Does DTC reset as a current DTC?
--
Go to Step 9
Go to Diagnostic System Check - ABS

7
Replace wheel speed sensor. Refer to Wheel Hub/Speed Sensor Replacement in Front Suspension.

Is the repair complete?
--
Go to Step 10
--

8
If the resistance was low, check for short between CKTs 873 and 830. If the resistance is high, check for an open in CKTs 873 or 830. If repair of the jumper harness is needed, replace the jumper harness. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?
--
Go to Step 10
--

9
Replace EBTCM. Refer to Electronic Brake Control Module (EBCM) Replacement .

Is the replacement complete?
--
Go to Step 10
--

10
Carefully test drive vehicle above 24 Km/h (15 mph) while monitoring a scan tool for at least 30 seconds.

Does the DTC set as a current DTC?
--
Go to Step 2
Go to Diagnostic System Check - ABS

The same procedure applies for the other three wheel speed sensors. All that changes is the connector pin where you make the measurements.
Have you checked the EBCM ground G108 over by the battery? You should also check the voltage at the EBCM to see if it is at battery voltage.

Have you made any changes to the lighthing system? Changing the stop light bulbs might screw up the stop light switch signal that goes to the EBCM. This signal tells the EBCM that the brake pedal is applied.

To get the symptoms you are describing the EBCM has to think the car is still moving and one or more wheels are locked up. If one wheel speed sensor is indicating the car is moving then the EBCM will release the brakes on the other 3 wheels. Since you are getting speed variations on all 4 sensors it seems there must be a common source for the problem which may be a voltage or ground. A high resistance in the ground circuit may make the system more susceptible to radiated electrical noise that may be near you such as cell phones, etc. That may explain the randomness of the events.

TOO!! much info for this duckin fummy to absorb!!:burnout: :burnout:

:rofl:

I think we are the only silly ones up this time of night!

NOPE!! YA got other sillys out there !!!!!!!!!:burnout: :burnout: :burnout: