Help! Abs and tcm lights stay on

[GULFTANGO]

First time for this problem. When starting car everything is normal, all lights go off then the ABS and TCM lights come back on. Traction Control switch on center console does not work when this started happening, but did before. No other brake light warning or steering warning comes on. Car drives normal and brakes normal. Both lights initially and ever since come on at the same time. Reset codes but it continues to happen repeatily. Sounds like its electrical? Just trying to get a heads up before I take it to the dealer.

 

[dadaroo]

Well, are you going to pull the codes so we have something to work on?

 

[YumaZ06]

Codes...codes...codes? How old is your battery?

 

[GULFTANGO]

Well, are you going to pull the codes so we have something to work on?

The codes are: C1241, C1255, C1276, U1040. Battery less than 6 months old.

 

[gmjunkie]

The codes are: C1241, C1255, C1276, U1040. Battery less than 6 months old.

First thing,You need to clean and inspect ALL Grounds!

The ones on top the fame by the headlamps are probly purdy nasty internally,Will cause EBCM malfunction!

C5 Ground Locations

 

[dadaroo]

These codes are:

C1241 Magna Steer Circuit Malfunction (variable steering)

C1255 EBCM internal malfunction

C1276 Delivered Torque Signal Circuit Malfunction

U1040 Loss of communication with TCS

You did not indicate if any of these were History (H) versus Current (C). Please go for a ride and BEFORE you turn the engine off, pull the codes again and note if they show H or C.

Here is a Thread that you need to review. Focus on discussions and inspections starting on Post #16. Grounds, fuses, connectors and voltages. Not for the faint of heart.

In the meantime I will do some more research on these.

 

[GULFTANGO]

More Info

All codes are current. The first time these lights came on and stayed on, there were all sorts of warnings and alarms going off. After I reset them and cleared all codes the lights come on after I start driving and stay on, but no more warning alarms. Car drives the same before and after all this.

 

[dadaroo]

Sorry, forgot to add the Thread from above. Again look at: TCS No Comm ..... - Corvette Forum

Focus on discussions and inspections starting on Post #16. Grounds, fuses, connectors and voltages. Not for the faint of heart.

I have not finished looking at everything in the FSM but I think your EBCM is at the heart of this. With yours being a 1997 you will be challenged to fix/replace. I am not aware of any shop that repairs them. If it is a relay in it I have a link for the fix.

I don't like ABS and I turn off my TC.

 

[c4c5specialist]

HI there,

In the interest of accurate information here, your C1255 is where you should start.

A DIC code read will never give you the SUBCODE to the C1255, and that is what you need first to accurately diagnose if you do or do NOT have a ground source issue.

We do not measure ground resistance using OHMS anymore for control modules, we do a voltage drop check back to negative battery.

20 millivolts is the MAXIMUM you should have.

As for the rest, wiring schematics are critical to your vehicle as there were some changes in wiring positions at the EBTCM depending on production.

Allthebest, Paul

 

[GULFTANGO]

Dealer evaluation

Chevy dealer said the EBCM is bad needs replacing. GM no longer carries this part. On Ebay a used one is between $1000-$2000.00. My question for you, what did you do to disconnect yours and did the lights on dash go off or did you do something else?

Sorry, forgot to add the Thread from above. Again look at: TCS No Comm ..... - Corvette Forum

Focus on discussions and inspections starting on Post #16. Grounds, fuses, connectors and voltages. Not for the faint of heart.

I have not finished looking at everything in the FSM but I think your EBCM is at the heart of this. With yours being a 1997 you will be challenged to fix/replace. I am not aware of any shop that repairs them. If it is a relay in it I have a link for the fix.

I don't like ABS and I turn off my TC.

 

[dadaroo]

Sorry if you misunderstood. I did not delete my ABS. I turn off the TC which disables Active handling also. Can't turn off ABS but if it does not work it does not affect normal braking function. With a pre 2001 one you are stuck without ABS and TC until someone comes along with a total fix. No biggy in my opinion.

Here is the link to the relay fix I spoke of:

★★★★★★★★★ ► CHUCK CoW NOW REPAIRS 1997 - 2000 DISCONTINUED C5 ABS UNITS ◄ ★★★★★★★★★ - Corvette Forum

 

[smith1]

Have same problem with 03 convertible

First time for this problem. When starting car everything is normal, all lights go off then the ABS and TCM lights come back on. Traction Control switch on center console does not work when this started happening, but did before. No other brake light warning or steering warning comes on. Car drives normal and brakes normal. Both lights initially and ever since come on at the same time. Reset codes but it continues to happen repeatily. Sounds like its electrical? Just trying to get a heads up before I take it to the dealer.

Hi, I am having the same problem with false abs and traction control malfunctions. when my abs light stays on, my air/heat will not work. after 10 or 15 minutes of driving, the abs symbol turns off and the air works again.. until the next time.. ed

 

[GULFTANGO]

Same thing

Mine did the same thing. Reset all codes and next morning it worked fine and still does. Chevy dealer says it is the EBCM module. No after market replacement for this item. Have a couple of specialty shops looking into the possibility of rebuilding this thing. I will post here any answers on this.[/QUOTE]

 

[smith1]

abs and tcm lights stay on

Mine did the same thing. Reset all codes and next morning it worked fine and still does. Chevy dealer says it is the EBCM module. No after market replacement for this item. Have a couple of specialty shops looking into the possibility of rebuilding this thing. I will post here any answers on this.

[/QUOTE]

I have also had the dealers reset th codes, but the malfunction happens again and again.. they also put in new modules twice.. still doesn't work after awhile.. I am at my wits end to find an answer.. any help will be most appreciated.. I am taking it ot a corvette specialist this week here in tampa florida.. thanks .. ed

 

[GULFTANGO]

Interesting

Please post here when you get any answer from them, good or bad.

I have also had the dealers reset th codes, but the malfunction happens again and again.. they also put in new modules twice.. still doesn't work after awhile.. I am at my wits end to find an answer.. any help will be most appreciated.. I am taking it ot a corvette specialist this week here in tampa florida.. thanks .. ed[/QUOTE]

 

[dadaroo]

I have also had the dealers reset th codes, but the malfunction happens again and again.. they also put in new modules twice.. still doesn't work after awhile.. I am at my wits end to find an answer.. any help will be most appreciated.. I am taking it ot a corvette specialist this week here in tampa florida.. thanks .. ed[/QUOTE]

You don't need the dealer to reset codes. What were the codes you had or are having. Sounds like a U communication issue with the serial bus if the HVAC goes out at the same time.

 

[GULFTANGO]

Acts like a computer virus

NEW ELECTRONIC PROBLEMS



SATURDAY
1. "TCS" LIGHT CAME BACK ON.
2. "SERVICE ENGINE SOON" LIGHT CAME ON (STEADY NOT FLASHING)
3. CLEARED ALL CODES. CAR WOULD NOT RESTART.
4. LET IT SIT OVERNIGHT.


SUNDAY
1. CAR STARTED NORMAL, DISPLAY NORMAL, NO WARNING LIGHTS ON DASH. TOOK CAR OUT, DROVE NORMAL AFTER ABOUT 5 MILES, NOTICED SPEEDOMETER DID NOT WORK. SHUT CAR OFF. CHECKED CODES AND RESET ALL. CAR WOULD NOT START. LET IT SET A FEW MINUTES AND IT STARTED NORMAL. DROVE ABOUT ONE BLOCK AND "SERVICE ENGINGE SOON" LIGHT CAME BACK ON (STEADY) SPEEDOMETER DID NO WORK, AND "TCS" LIGHT CAME ON AND WOULD NOT GO OFF. ALL READINGS IN THE "DIC" WERE FROZEN AND DID NOT SHOW CAR MILAGE, TRIP, AIR PRESURE, BUT ALL GAUGES APPEARED TO BE READING CORRECTLY EXCEPT SPEEDOMETER STAYED ON ZERO. TURNED CAR OFF WOULD NOT RESTART, SOUNDED LIKE A DEAD BATTERY. CLEARED CODES AND CAR RESTARTED NORMAL, DROVE IT HOME, ALL THIS HAPPENED WITHIN 30 MINUTES.
2. NEW CODE SHOWED UP WHEN I GOT HOME (P0341), C1241 & C1286 ALSO SHOWED AS NEWHOME. RESET ALL CODES AND LET IT SIT OVERNIGHT.
3. DURING ALL THIS THE TACH WORKED FINE. THE "ABS" LIGHT NEVER CAME ON, INDICATING A BRAKE PROBLEM.

I have also had the dealers reset th codes, but the malfunction happens again and again.. they also put in new modules twice.. still doesn't work after awhile.. I am at my wits end to find an answer.. any help will be most appreciated.. I am taking it ot a corvette specialist this week here in tampa florida.. thanks .. ed

You don't need the dealer to reset codes. What were the codes you had or are having. Sounds like a U communication issue with the serial bus if the HVAC goes out at the same time.[/QUOTE]

 

[GULFTANGO]

Forgot to mention

Car came back from dealer on Friday. They cleaned and dried out EBCM. Said computer board was toast. Gave me the number on it #09356911 (no M), then came the weekend stuff listed.

NEW ELECTRONIC PROBLEMS



SATURDAY
1. "TCS" LIGHT CAME BACK ON.
2. "SERVICE ENGINE SOON" LIGHT CAME ON (STEADY NOT FLASHING)
3. CLEARED ALL CODES. CAR WOULD NOT RESTART.
4. LET IT SIT OVERNIGHT.


SUNDAY
1. CAR STARTED NORMAL, DISPLAY NORMAL, NO WARNING LIGHTS ON DASH. TOOK CAR OUT, DROVE NORMAL AFTER ABOUT 5 MILES, NOTICED SPEEDOMETER DID NOT WORK. SHUT CAR OFF. CHECKED CODES AND RESET ALL. CAR WOULD NOT START. LET IT SET A FEW MINUTES AND IT STARTED NORMAL. DROVE ABOUT ONE BLOCK AND "SERVICE ENGINGE SOON" LIGHT CAME BACK ON (STEADY) SPEEDOMETER DID NO WORK, AND "TCS" LIGHT CAME ON AND WOULD NOT GO OFF. ALL READINGS IN THE "DIC" WERE FROZEN AND DID NOT SHOW CAR MILAGE, TRIP, AIR PRESURE, BUT ALL GAUGES APPEARED TO BE READING CORRECTLY EXCEPT SPEEDOMETER STAYED ON ZERO. TURNED CAR OFF WOULD NOT RESTART, SOUNDED LIKE A DEAD BATTERY. CLEARED CODES AND CAR RESTARTED NORMAL, DROVE IT HOME, ALL THIS HAPPENED WITHIN 30 MINUTES.
2. NEW CODE SHOWED UP WHEN I GOT HOME (P0341), C1241 & C1286 ALSO SHOWED AS NEWHOME. RESET ALL CODES AND LET IT SIT OVERNIGHT.
3. DURING ALL THIS THE TACH WORKED FINE. THE "ABS" LIGHT NEVER CAME ON, INDICATING A BRAKE PROBLEM.

You don't need the dealer to reset codes. What were the codes you had or are having. Sounds like a U communication issue with the serial bus if the HVAC goes out at the same time.

[/QUOTE]

 

[dadaroo]

The nest time you have an issue I need to know what ALL the codes are that show. At this point we don't really care about anything EBCM, TC, or AH. I want to focus on why no start and the other issues.

PS: P0341 is the Camshaft Position Sensor Circuit Performance. Could be related to your starting issue

 

[GULFTANGO]

Monday test

1. Started car. initial gauge check was completely normal, except "Check Engine Soon" light stayed on. Took car out on short drive. Speedometer working, ABS and TCS working, DIC working. All appeared normal. After 1/2 mile speedometer stopped working. Parked car, tried to restart and would not, sounded like low battery.

2.Checked all codes. Here are all codes showing current, no other codes displayed.
P0342
C1241
C1286
Did not reset codes. Will go out later and try to start.

The nest time you have an issue I need to know what ALL the codes are that show. At this point we don't really care about anything EBCM, TC, or AH. I want to focus on why no start and the other issues.

PS: P0341 is the Camshaft Position Sensor Circuit Performance. Could be related to your starting issue