klymaxr

p1571,c1277 codes wont clear!!

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Just installed a new stroker 428ci and after doing a wash of the engine compartment (coincidence??) I had these codes and the traction control light on the dash was lit up and at first the engine ran in a sort of limp mod but has since gone away but the codes still pop up. I dried every connecter to the ABS unit as well as the connecters along the frame heading to the wheels. now after that the abs light would appear intermitently ( it would clear and then not come back on for a couple of days) The steering rack was taken out several time to fix a small oil leak as well and I also installed the new C-6 Z06 brake package. Can anyone tell me, other than that the ABS might be pooched (worked perfectly for 30,000klm), what could be the cause...thanks in advance.

SilvaDragon

OK, so both of those codes are related to the traction control.
You don't mention if the car is an automatic or stick, and these
codes tend to be more common on automatics.

It sounds like the computer is upset because the new engine is
making more power than it is programmed to handle in the
traction control system tables.

If you do some digging around for Torque Control, you might
find some more information.

klymaxr

It is an auto and the torque reduction has been edited off in the trans table. the engine is making in the neighborhood of 550rwhp 540rwtq NA 700 on a 125 shot. but the codes never showed up last yrar with only 20hp less. seamed as if it came about after stering was removed and re instaled or when the engine bay was washed???

Bill Dearborn

The P1571 indicates the PCM is not receiving the requested torque signal from the EBCM or the signal is out of the normal range. The PCM provides a 5 volt signal which the EBCM then alternately shorts to ground producing a signal alternating from 5V to 0V and back. The duty cycle of this signal tells the PCM how much to reduce torque. Normal duty cycle values of the signal are from 10% to 90%. If the signal is 0 all of the time or +5V all of the time that would be out of the normal range. C1277 basically says the same thing. Not sure what you meant when you said you dried the connectors. Check and clean your grounds at G101 (EBCM) and G108 (PCM).

The fact that it is working some of the time indicates your tuner's program has nothing to do with the problem. In a case like this software either works or it doesn't work it isn't intermittent.

Bill

klymaxr

thanks bill,where are these locations ..g101/g108. the drying issue was just in case i got something wet since i had washed the engine compartment just prior to the misshaps.

Bill Dearborn

I misspoke a little. Depending on what year car you have the terminology changes a little. Sometimes it is hard to tell whether they changed the name or actually changed the circuit layout based on the year. G101 provides the ground for the BPMV and is located on the left frame rail in front of the windshield washer reservoir. G108 provides the EBCM ground and it is located in the forward lamp harness, below the battery tray on the frame rail (CKT 1251). The PCM ground is G106 which is located in the engine harness, RH side of the engine, above the starter (CKT 451). For the latter years the EBCM gets a different ground designation for controlling the BPMV which is G103 which is located in the G103 Forward lamp harness, on LH frame rail, near brake pressure modulator valve (BPMV) (CKT 1250) which is basically the same spot as G101. If you clean the contacts at these ground points you should cover the various configurations. Hopefully, that solves your problem.

Bill

Trucker5262

Hi Bill, I have a question for you. I have a2001 c5 Corvette, ok 2016 I sent the ebcm to get fix, everything was working ok after that fix, then I put my car ok storage, on November 2017, winter, I pulled it out on March 2018 this year, I disconnected the battery for those months, when I picked my car up I reconnected the battery and when I try to start it up I got the normal messages on dic, Corvette, by GMC, but the third messages was check engine soon, as soon as I started my car this third message went off. I checked the codes and I found u1040 and b0432, I sent back the ebcm to get refix, and put it back on and the codes are still there. I should tell you that 2 times out of 6 starting cycles, same messages, but the abs and active handling lights have came on and after starting up the car after few seconds the abs light goes off and the active handling light remains on, I have checked the codes and besides the two that I said before I have found p15725 and c1277, I cleared those codes but as soon as I clear the c1277 and p1571 I have heard a crack noise coming from the engine compartment and the light goes off immediately, the car runs ok without any issue. By the way I put a brand new battery.
Please tell what do you think could be the problem.
Thanks in advance. Every time that I have cleared the codes the car runs very well, and the codes that are always there are u1040 and b0432.
Thank you so much