Help me please! Reduced Engine Power...Service Traction System...
Thread Starter
Heel & Toe
Joined: Feb 2007
Posts: 21
Likes: 0
From: San Antonio Texas
Help me please! Reduced Engine Power...Service Traction System...
Started a few days ago while driving got reduced engine power, service traction system in DIC. Pulled over shut down car and restarted messages went away. When I went to leave work same thing happened. Yesterday as well but the problem became more persistent.
Pulled the codes, this is what I got:
PCM:
p1221 H
p1571 H
TCS:
c1278 H
HVAC:
B0361 HC
B0441 HC
BCM:
B2723 H
Radio:
U1016 H
Any help would be greatly appreciated, If it matters it had been raining for about a week here in San Antonio when this started.
Pulled the codes, this is what I got:
PCM:
p1221 H
p1571 H
TCS:
c1278 H
HVAC:
B0361 HC
B0441 HC
BCM:
B2723 H
Radio:
U1016 H
Any help would be greatly appreciated, If it matters it had been raining for about a week here in San Antonio when this started.
Race Director
Joined: Aug 2001
Posts: 17,901
Likes: 18
From: Elko, Nevada
I can tell you what the codes technically are, but why you are getting them I cannot.
PCM:
p1221 H = TP Sensors 1, 2 Performance
p1571 H = ASR Desired Torque
TCS:
c1278 H = TCS Temporarily Inhibited By PCM
I had the samething years ago...and the traction control system needed to be 'serviced'...whatever the hell that means. Thank goodness I was under warranty.
PCM:
p1221 H = TP Sensors 1, 2 Performance
p1571 H = ASR Desired Torque
TCS:
c1278 H = TCS Temporarily Inhibited By PCM
I had the samething years ago...and the traction control system needed to be 'serviced'...whatever the hell that means. Thank goodness I was under warranty.
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
Maybe this will help .....
P1221 .... your throttle is opened and closed by an electric motor ... the accelerator pedal that you step on is a "fly by wire" system. Inside the throttle there are two sensors that report the position of the throttle plate. There are two so if one fails you aren't stranded, or worse, wrecked because the throttle plate can't be accurately controlled without the feedback of where the plate is located. The P1221 sets when the PCM gets inconsistent or conflicting data from the two sensors.
You need to look at the wiring to the throttle and make sure all connections are good. If you are satisfied you don't have a wiring problem, replace the throttle position sensors. This is an easy repair you can do yourself in 5 to 10 minutes. Basically disconnect wiring, unscrew two mounting screws, pull off old sensor and install new sensor, attach with two screws, hook up wiring .... DONE. No jacking the car up .... the part is easy to reach ..... you'd be crazy not to fix it yourself.
If you need more info, post again, if you need part numbers post what model year your car is.
P1571 ... This code will clear when you fix the Throttle Position Sensors (TPS). The PCM sets this code whenever certain TPS codes set. This code causes the PCM to send a message to the Electronic Brake Control Module (EBCM) that basically says "I can't reliably control the throttle so don't have Traction Control try to use the "REQUESTED TORQUE" signal wire to ask for reduced torque."
C1278 ... This code will also clear when you fix the TPS problem. This code results from the P1571. The EBCM has shut off Traction Control in response to the message it received from the PCM. This code sets so that a technician knows that the TC system is down because of the PCM problem, not for some other problem.
The two HVAC codes indicate a problem with the LEFT actuators. Let's get the TPS problem fixed and then we can attack the actuator problems.
Since the two other codes (Radio and BCM) are History, and the BCM code must be old or you would be unable to start the car with it in a "Current" status .... just delete them.
P1221 .... your throttle is opened and closed by an electric motor ... the accelerator pedal that you step on is a "fly by wire" system. Inside the throttle there are two sensors that report the position of the throttle plate. There are two so if one fails you aren't stranded, or worse, wrecked because the throttle plate can't be accurately controlled without the feedback of where the plate is located. The P1221 sets when the PCM gets inconsistent or conflicting data from the two sensors.
You need to look at the wiring to the throttle and make sure all connections are good. If you are satisfied you don't have a wiring problem, replace the throttle position sensors. This is an easy repair you can do yourself in 5 to 10 minutes. Basically disconnect wiring, unscrew two mounting screws, pull off old sensor and install new sensor, attach with two screws, hook up wiring .... DONE. No jacking the car up .... the part is easy to reach ..... you'd be crazy not to fix it yourself.
If you need more info, post again, if you need part numbers post what model year your car is.
P1571 ... This code will clear when you fix the Throttle Position Sensors (TPS). The PCM sets this code whenever certain TPS codes set. This code causes the PCM to send a message to the Electronic Brake Control Module (EBCM) that basically says "I can't reliably control the throttle so don't have Traction Control try to use the "REQUESTED TORQUE" signal wire to ask for reduced torque."
C1278 ... This code will also clear when you fix the TPS problem. This code results from the P1571. The EBCM has shut off Traction Control in response to the message it received from the PCM. This code sets so that a technician knows that the TC system is down because of the PCM problem, not for some other problem.
The two HVAC codes indicate a problem with the LEFT actuators. Let's get the TPS problem fixed and then we can attack the actuator problems.
Since the two other codes (Radio and BCM) are History, and the BCM code must be old or you would be unable to start the car with it in a "Current" status .... just delete them.
Racer
Joined: Oct 2008
Posts: 287
Likes: 1
Maybe this will help .....
P1221 .... your throttle is opened and closed by an electric motor ... the accelerator pedal that you step on is a "fly by wire" system. Inside the throttle there are two sensors that report the position of the throttle plate. There are two so if one fails you aren't stranded, or worse, wrecked because the throttle plate can't be accurately controlled without the feedback of where the plate is located. The P1221 sets when the PCM gets inconsistent or conflicting data from the two sensors.
You need to look at the wiring to the throttle and make sure all connections are good. If you are satisfied you don't have a wiring problem, replace the throttle position sensors. This is an easy repair you can do yourself in 5 to 10 minutes. Basically disconnect wiring, unscrew two mounting screws, pull off old sensor and install new sensor, attach with two screws, hook up wiring .... DONE. No jacking the car up .... the part is easy to reach ..... you'd be crazy not to fix it yourself.
If you need more info, post again, if you need part numbers post what model year your car is.
P1221 .... your throttle is opened and closed by an electric motor ... the accelerator pedal that you step on is a "fly by wire" system. Inside the throttle there are two sensors that report the position of the throttle plate. There are two so if one fails you aren't stranded, or worse, wrecked because the throttle plate can't be accurately controlled without the feedback of where the plate is located. The P1221 sets when the PCM gets inconsistent or conflicting data from the two sensors.
You need to look at the wiring to the throttle and make sure all connections are good. If you are satisfied you don't have a wiring problem, replace the throttle position sensors. This is an easy repair you can do yourself in 5 to 10 minutes. Basically disconnect wiring, unscrew two mounting screws, pull off old sensor and install new sensor, attach with two screws, hook up wiring .... DONE. No jacking the car up .... the part is easy to reach ..... you'd be crazy not to fix it yourself.
If you need more info, post again, if you need part numbers post what model year your car is.
Where are these throttle connections located in the car so I can take a look at them?
Thanks for the help.
Tech Contributor
Joined: Jan 2007
Posts: 19,473
Likes: 1,171
From: Dyer, IN
the thread you posted on has not had a comment in 4 months, better off starting your own thread for your problem.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
SimpleC6
You have a 2005 C6. You should post in the C6 Tech forum. Your TB is a LOT different than a C5 TB. It works the same way but you have an entirely different type of connection and the Throttle Position Sensor is inclosed inside the housing. Make sire that the black connector on the pasengers side of the TB is installed in the TB connector properly.
Lucky. Have you seen or herd of any post from BLACKZO6?? I tried to PM him and his box is FULL!
He's been MIA for months. 
Bill
You have a 2005 C6. You should post in the C6 Tech forum. Your TB is a LOT different than a C5 TB. It works the same way but you have an entirely different type of connection and the Throttle Position Sensor is inclosed inside the housing. Make sire that the black connector on the pasengers side of the TB is installed in the TB connector properly.
Lucky. Have you seen or herd of any post from BLACKZO6?? I tried to PM him and his box is FULL!
He's been MIA for months. Bill
Tech Contributor
Joined: Jan 2007
Posts: 19,473
Likes: 1,171
From: Dyer, IN
SimpleC6
You have a 2005 C6. You should post in the C6 Tech forum. Your TB is a LOT different than a C5 TB. It works the same way but you have an entirely different type of connection and the Throttle Position Sensor is inclosed inside the housing. Make sire that the black connector on the pasengers side of the TB is installed in the TB connector properly.
Lucky. Have you seen or herd of any post from BLACKZO6?? I tried to PM him and his box is FULL! He's been MIA for months.
Bill
You have a 2005 C6. You should post in the C6 Tech forum. Your TB is a LOT different than a C5 TB. It works the same way but you have an entirely different type of connection and the Throttle Position Sensor is inclosed inside the housing. Make sire that the black connector on the pasengers side of the TB is installed in the TB connector properly.
Lucky. Have you seen or herd of any post from BLACKZO6?? I tried to PM him and his box is FULL!
He's been MIA for months. Bill
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Joined: Apr 2020
Posts: 1
Likes: 0
Ignition Interlock Devise
My 2010 C6 (apologies that this is a C5 Tech) is doing the same thing " Service Traction System, then says "Reduced Engine power" It will go away if I restart it, but comes back in a few minutes. It does reduce my power for sure. Sometimes not even enough to pull into a driveway. My question is Last year I had an ignition interlock system put in the car. A " blow box" if you will, as a result of a DUI. Before parking it for the season, I had them remove it. It seems all this started after this. Not to the day, but closely thereafter. Does anyone think the installation/ removal of this system screwed something up? I've tried to talk to the tech and they never came back to me.
