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Im having an issue with my vette after a dramatic stop my car stated "service traction control" "service abs" etc.Now my brake light stays on so as for the TCS light stays on.I tried to reset the code what came up was C1247 and I try to erase it and it wont go away it will pop back up that same second im running out of ideas literally any advice would help thanks..
The EBTCM monitors the Brake Pressure Differential Switch to turn off Traction Control and Active Handling if a pressure loss is detected in the hydraulic brake system.
Conditions for Setting the DTC
DTC C1247 can be set anytime, if the EBTCM detects the Brake Pressure Differential Switch has been grounded due to loss of brake pressure or a short to ground.
Action Taken When the DTC Sets
TCS/Active Handling are disabled.
Indicators that turn on:
RED Brake Warning indicator
Car Icon (TCS indicator)
Messages displayed on the DIC:
Service Traction System
Service Active HNDLG
Conditions for Clearing the DTC
Condition for DTC is no longer present and scan tool clear DTC function is used.
Fifty ignition cycles have passed with no DTCs detected.
Diagnostic Aids
DTC C1247 could be set during a hydraulic brake system bleeding procedure if the ignition switch is in the ON position.
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 number(s) below refer to the step number(s) on the diagnostic table.
This step checks for a short to ground in the Brake Pressure Differential Switch circuit.
This step indicates that the Brake Pressure Differential Switch circuit is operating properly, and the cause of the DTC is a failure in the hydraulic brake system.
1
Was the Diagnostic System Check performed?
--
Go to Step 2
Go to Diagnostic System Check - ABS
2
Turn the ignition switch to the OFF position.
Disconnect the Brake Pressure Differential Switch connector.
Turn the ignition switch to the ON position, engine off.
Does the Red BRAKE Warning Indicator remain on?
--
Go to Step 3
Go to Step 4
3
Repair circuit 1659 for a short to ground. Refer to Wiring Repairs in Wiring Systems.
Is the repair complete?
--
Go to Diagnostic System Check - ABS
--
4
The Brake Pressure Differential Switch is working properly. Refer to Hydraulic Brake Diagnostic System Check in Brakes.
Is the repair complete?
--
Go to Diagnostic System Check - ABS
--
Thanks man atleast someone replyed.So in order to set the code back is to bleed the brakes and try to erase it at the same time??Or bottom out the brake pedal and set it like that??Thats the only thing I can think off??One question when I try to erase the code C1247 it wont erase it will pop back up within the same sec.
What it is saying is that you have some equaliztion (pressure) problem in your braking system.
Your EBCM could have gone or maybe you sucked air into your system, etc ...
Start by checking your brakes system. Pull your wheels and check the brake lines, hoses, calipers, etc... for leaks.
Check the resevoir for fluid loss. You can try and bleed the brakes ans see if that helps.
If not then you'll need to get somewhere, to have a Tech2 and try to do an automated bleed of the system and to check your wiring.
BTW, The bleeding of the brakes could be a cause not a fix in your above reply.
Originally Posted by 427TTA4
Thanks man atleast someone replyed.So in order to set the code back is to bleed the brakes and try to erase it at the same time??Or bottom out the brake pedal and set it like that??Thats the only thing I can think off??One question when I try to erase the code C1247 it wont erase it will pop back up within the same sec.
What it is saying is that you have some equaliztion (pressure) problem in your braking system.
Your EBCM could have gone or maybe you sucked air into your system, etc ...
Start by checking your brakes system. Pull your wheels and check the brake lines, hoses, calipers, etc... for leaks.
Check the resevoir for fluid loss. You can try and bleed the brakes ans see if that helps.
If not then you'll need to get somewhere, to have a Tech2 and try to do an automated bleed of the system and to check your wiring.
BTW, The bleeding of the brakes could be a cause not a fix in your above reply.
Im actually doing the inspection right now as I type..What I dont get is that when I rev the engine past 4000rpm it says reduced engine power and sounds like it runs on 4 cylinders???Could that cause it to do that???
The motor is probably cutting out because you reving it while not moving.
Pull your codes from your DTC.
The IPC display, the 20-character, vacuum florescent screen above the steering column that says "Corvette by Chevrolet" every time you turn on the key, is a powerful device. DIY Service Techs are going to be most interested in the IPC's ability to show diagnostic trouble codes (DTC) for all the modules that transmit them.
The "diagnostic display" mode is entered with the following procedure:
1. Turn on the ignition but don't start the engine.
2. Press the "reset" button to turn off any warning messages
3. Press and hold "options" and
4. While holding "options", press "fuel" four times within a 10-second period.
Inititially, the on-board diagnostics go into the "automatic" mode which shows each module's DTCs in a pre-set sequence:
• 10 PCM Powertrain Control Module page 6-357 - 6-361
• 28 TCS Traction Control system ABS on page 5-86
• ?? RTD Real Time damping page 3-136 (I do not have this option)
• 40 BCM Body Control Module page 8-405 UTD Page 8-727
• 60 IPC Instrument Panel Cluster page 8-508
• 80 radio page 8-213
• 99 HVAC Heater Vent-Air Conditioning page 1-118
• A0 LDCM Left Door Control module page 8-904 to 8-951
• A1 RDCM Right Door Control Module page 8-904 to 8-951
• AC SCM Seat Control module page 8-1064 -8-1082
• B0 RFA Remote Function Actuation page 8-676
For each module, all DTCs will be displayed. If none are present in a module, you will see "no more codes" on the ICP display.
There are two kinds of DTCs, "Current" and "History," designated with a letter suffix, "C" or "H". A current code indicates that the malfunction is present in the system whose module is displaying data. A history code indicates a problem existed in that module sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it is possible it's evidence of a previous problem, now solved, that was not removed by clearing codes. More likely is that a history code indicates an intermittent malfunction. "Intermittents" are the most challenging DTCs. An intermittent may have happened only once, may have happened more than once but is inconsistent in its appearance or may be happening on a regular basis but not at the time the IPC is displaying codes. History codes can also be caused by a current malfunction in a system that is not operating at the time DTCs are displayed. An example is the rear window defogger which doesn¹t operate until the BCM detects engine rpm. For history codes set by a system that does not operate with the key on and engine off, a special diagnostic tool called a "scan tester" is necessary to properly diagnose the malfunction.
Once the IPC has displayed all 11 modules, the system goes into the manual mode which allows selection of each module using combinations of DIC buttons. The manual mode can also be entered at any time during the automatic sequence by pressing any button except "E/M". Once the IPC displays "manual diagnostics," you may select a particular module by pressing the "options" button to go forward or the "trip" button to go back. Once a system is selected and a DTC is displayed, if more than one are present; press "gages" to move forward or "fuel" to go back.
To exit the diagnostic mode at any time, press "E/M". If you want to erase or "clear" codes, press "reset." Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory.
I recently blew a rear brake line do to a corroded rear passenger hardline. I repaired the line and bled the brakes and was still left with code c1247 brake pressure differential switch activated. I tried to reset the code but I couldn’t erase it. I lost the use of the traction control button and active handling.
After some research I found that the switch was located on the brake combination valve under the master cylinder.
The fix is to take off the windshield wiper fluid reservoir and unplug and remove the switch from the brake combination valve (17mm open end wrench.) Once removed you will need to side the bolt forward or backwards to align the sight hole with the valley of the bolt. Then the plunger on the switch will be fully extended and there will be no more c1247.
If there is still a code reset it through the DIC and it will be erased. No more code and active handling now will work.
This is not the gm valve I just used a stock photo to explain what is happening inside the unit.
10-22-2010, 04:31 AM
C1247 brake pressure differential switch activated.
im running out of ideas literally 
any advice would help thanks.. 
