Like to know what this code refers to. P1571
Thread Starter
Instructor
Joined: Jul 2005
Posts: 103
Likes: 1
Like to know what this code refers to. P1571
Hey Guys
Have these codes in my history and would like to know what it means.
97 AT
PCM: P1571---ASR Desired torque
Also
28 TCS:C1277---Requested Torque Signal CKT Malfunction
28TCS:C1225---Left front- Excessive wheel speed variation
Thanks
Have these codes in my history and would like to know what it means.
97 AT
PCM: P1571---ASR Desired torque
Also
28 TCS:C1277---Requested Torque Signal CKT Malfunction
28TCS:C1225---Left front- Excessive wheel speed variation
Thanks
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
The Electronic Brake Control Module (EBCM) has software in it for performing Traction Control. One way it does this is by requesting the Powertrain Control Module (PCM) to deliver less engine torque, allowing the rear wheels to regain traction. This is done using two signals .... one from the EBCM to the PCM that is a "requested torque" signal ..... the other is a signal from the PCM to the EBCM that is a "delivered torque" signal.
The P1571 is set by the PCM when it receives an invalid requested torque signal, or no signal at all.
The C1277 is set by the EBCM when it receives an invalid delivered torque signal, or no signal at all.
These are indicative of either bad EBCM grounds, or wiring corrosion on the connectors to the EBCM and/or PCM
The C1225 is set when the EBCM sees speed variations that cannot possibly occur .... the wheel speed sensor on that wheel has reported the wheel speed changed by more than 10 MPH in less than 0.01 seconds, and this must occur at least three times with no more than 0.2 seconds between occurancces. This DTC is usually a grounding problem for the wheel speed sensors. Do you have stainless steel brake lines on the car ??
The P1571 is set by the PCM when it receives an invalid requested torque signal, or no signal at all.
The C1277 is set by the EBCM when it receives an invalid delivered torque signal, or no signal at all.
These are indicative of either bad EBCM grounds, or wiring corrosion on the connectors to the EBCM and/or PCM
The C1225 is set when the EBCM sees speed variations that cannot possibly occur .... the wheel speed sensor on that wheel has reported the wheel speed changed by more than 10 MPH in less than 0.01 seconds, and this must occur at least three times with no more than 0.2 seconds between occurancces. This DTC is usually a grounding problem for the wheel speed sensors. Do you have stainless steel brake lines on the car ??
Pro
Joined: Nov 2002
Posts: 717
Likes: 11
From: Pleasanton CA
I chased these codes, P1571 & C1277 in my 01 for weeks and cleared them by replacing the ignition switch. Look up a post by Bill Curlee on this topic 
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
Race Director
Joined: Aug 2001
Posts: 11,028
Likes: 5
From: Chicago (Naperville) IL
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Safety Car
Joined: Dec 2004
Posts: 3,526
Likes: 20
From: Santa Fe TX
P1571H that cannot be cleared is a known problem with 1997 PCMs. I think there is a TSB.
Excessive Wheel speed variation -- do you have stock tire sizes on the front?
For 1277 check the grounds.
Excessive Wheel speed variation -- do you have stock tire sizes on the front?
For 1277 check the grounds.
Race Director
Joined: Aug 2001
Posts: 11,028
Likes: 5
From: Chicago (Naperville) IL
how can I find the TSB number? I do have stock sizes in front for now, but the Summer rims are 18s in the front same width
which grounds for the 1277 code?
Thanks!
Burning Brakes
Joined: Nov 2006
Posts: 1,040
Likes: 0
From: Auburn Georgia
Here is what I could find on your predictament:
http://www.digitalcorvettes.com/foru...ad.php?t=82349
Good luck!
http://www.digitalcorvettes.com/foru...ad.php?t=82349
Good luck!
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
Scroll down to post #11 in this thread .....
http://forums.corvetteforum.com/show...p?p=1564871489
Bill Dearborn is a reliable source ... so looks like the presence of a P1571H in a 1997 that cannot be cleared is a "known" problem, and should just be ignored.
