Hey everybody-

I just bought a 98 C5 and its throwing these codes at me:

10-PCM P1571 HC
28-TCS NO COMM
38-RTD C1780 HC

Wondering if you can help me figure out what's going on and what the next step is. Everything I'm reading is pointing to the ABS Module and ABS Fixer has come highly recommended. What are the thoughts of the group? Thanks all!!

 

I'm in the same boat as you.. Except some different codes..
I just got a 97 c5 and both of those lights are on. If you find a solution please let me know and I'll do the same

 

This seems to be a common problem with the earlier C5's. The bad news is that the part that you need (EBCM) was discontinued a long time ago and even worse the 97 to 2000 EBCM cannot be repaired. You will have to replace the unit which can cost anywhere from $600 to 1200+ for used unit (depends on ebay prices etc). This excludes labor etc. as the unit will most likely need to be bled using a TechII which the dealer has.

Sorry to tell you the bad news but this is one of the main reasons I am just saving up a little bit longer to get an 01 or 02 C5 Although alot of people who own the 97 to 2000 models will say they never had that problem, I just want that peace of mind considering I do all my work by myself

 

I'm not sure if I would want to drive a C5 without any of the braking safety features (no abs, TCS, etc.) But that's just me lol.

 

I guess there may not be any classic muscle cars in your future. In the 60's we had more HP and Torque in many of our cars and we did it on Bias Ply tires. Some of us survived and some did not.

In time, there should be some company (hopefully with GM support) to resolve the EBCM repair/replacement issues. I would guess it will take another 5 to 10 years.

Technology can be a good thing so long as it does not fail you when you are relying on it. AH failures at speed have caused a lot of C5 owners to change their underwear. Working with 2 such Forum members as we discuss this.

Have fun and be safe. Mr. Sam

 

LOL I think we have a misunderstanding. What I meant was that I would not drive a car that has its safety features that control something important as brakes, disconnected. In other words I would not disconnect something that intercepts steel brake lines to each wheel and think its now ok to drive around like that. Then I also believe if you bought a car with certain features, all those features should be fully operational. Thats just me

Man I really hope you are right about someone resolving the "obselete" or "non-repairable" EBCM issues the 97 to 2000's have. I once had an EBCM malfunction on my old Escalade and yes, speak about (almost) having to change underwear lol. The suv refused to come to a full stop and the pedal kept pulsing. I almost took out about 4 cars in that monster.

Yes I do not see any old classics in my future but sure miss working on Dad's 57 black and chrome Bel Air, when I was about 10. You just had me thinking about that

 

Many people have just pulled the 2 EBCM fuses to disable faulty AH and preclude "sudden" lane changes, especially at the drag strip or road course at over 100mph.

You still retain normal braking but do not have ABS. For an experienced driver you can stop in a shorter distance with ABS off and that is confirmed by ABS engineers. ABS is really intended to keep poor drivers from fishtailing since they don't know how to panic stop without locking up the brakes and losing control.

Beer for everyone! Mr. Sam

 

Are you getting any Service Messages on the DIC such as Service ABS or Service Traction Control?

The P1571 code means the PCM isn't receiving a requested torque signal from the EBCM. How this works is the PCM sends a plus 5 Volt signal to the EBCM and the EBCM modulates the signal to tell the ECM how much rear wheel torque should be applied.

Does this car have the Active Handling option? Look for JL4 on the RPO sticker in the glove compartment or on the storage compartment lids in the back.

Early 98s had their EBCM located by the differential (same as 97) and they only had ABS and Traction Control. After AH was introduced during the model year GM moved the EBCM location under the hood and in front of the engine on the driver's side.

There was a bulletin about the 97 and P1571 H Code and after reading the bulletin it looks like it applies to early 98s as well. Basically, it says the History (H) code is stuck on and should be ignored unless it is current (C).

#PI00219: History DTC P1571 Stored and Will Not Clear - (Jul 2, 2002)
Subject: History DTC P1571 Stored and Will Not Clear
Models: .
--------------------------------------------------------------------------------
When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Condition/Concern:
Vehicle may have a DTC P1571 [ASR (Automatic Slip Regulation) Desired Torque Circuit] stored in history that cannot be cleared. DTC C1277 (Requested Torque Signal CKT Malfunction) is NOT present and there is No Service Vehicle Soon lamp or powertrain related lamps on.

Recommendation/Instructions:
This is a normal condition. All 1997 YBs will have a DTC P1571 stored as history in the PCM that cannot be cleared. If P1571 is current, follow the trouble table in SI Document Number 101551. It should be noted that the schematic in this document incorrectly lists a ckt 449 dk blu/wht and calls it Real Time Dampening. This ckt is not present and should be ignored for both 97 and 98 (Document Number 203769) model year SI. A Service Information Update has been submitted.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

If you have been driving for 30 years or so you have driven many vehicles without ABS, Traction Control or Stability Control. Vettes didn't get ABS until 86, they didn't get Traction Control until 92 and didn't get stability control (AH) until 98. AH didn't become standard until 2000.

All of these systems ride on top of the base brake system which is basically the same kind of hydraulic brake system that has been installed in cars since the early 1930s or late 20s. The car will drive fine if they don't work. You will just have to threshold brake and be wiser with the use of the throttle. If all you do is drive on the street you more than likely will not notice those features aren't working.

Since you are getting a No Comm message for the TCS you should check the fuses to see if the EBCM is getting power. Check Fuses 5, 52 and 53 in the underhood electrical center. If the fuses are good and you have a front mounted EBCM you should check G108, the EBCM ground, which is located on the passenger side of the car under the battery. It is near G104. G101 is the ground for the BPMV which gets its 12V supply from the EBCM. If you have a rear mounted EBCM check the EBCM ground at G402. The BPMV ground is at G401.

You should also check the battery voltage level since No Comm may be an indication of battery capability or connection issues so you should check the battery posts, battery cable connectors at both ends of the battery cables to make sure you have good 12V and Ground connections.

If the EBCM is toast you will not be able to fix it or replace it. You won't be alone in this problem. From a Corvette standpoint the 2001-2004 EBCMs can be repaired if they have one specific failure related to code C1214 but are otherwise just as unrepairable as yours is. Even the C6 and C7 EBCMs are unrepairable as are the ones on all other cars. Once they die they can't be repaired and a large number of the modules may not be replaceable.

Bill

 

Well, I have read a lot of AH notes here on the forum and remain confused - mainly because I know nothing about any of this. I have an '02 with 35,000 miles. Great car. I have been getting "Service Active Handling" screen intermittently - 3-4 days just fine then nothing for a while then back on again. Just replaced brake pads all around. I don't drive the car hard at all and would be satisfied with normal disk braking. So can I just remove the fuses for the EBCM?

 

If you have read the notes on the forum you should know that you have to read the codes to determine what is causing the problem. You will need to use the dic to read the codes. http://www.stengel.net/diccodes.htm

 

Intermittent warnings are usually the abs sensors at the wheels... Well usually from most of the cars I've worked on

 

Thanks...that gives me something to check out.

 

oops

 

Please don't high jack someone else's Thread. Create your own. It is too difficult to solve multiple people's issues in one Thread. It is not a problem to create a Thread and then put a link to it here asking us to look at your problem.