C1281 Code. What is it?
Thread Starter
Instructor
Joined: Jul 2011
Posts: 198
Likes: 0
From: Hemet California
C1281 Code. What is it?
This code keeps coming back. It's only history when the car is off, but if I pull them up while the car is running, its a history and current. I looked it up, and it's Steering Sensor Uncorrelated Malfunction or Active Handling Sensors Uncorrelated, and it can't be the latter, because I don't have active handling. Any ideas as to what this means?
Race Director
Joined: Jul 2007
Posts: 18,681
Likes: 47
From: Reno is so close to Hell you can see Sparks , State Of Confusion
St. Jude Donor '12-'13-'14
Just to make sure, you are getting a Service Vehicle Soon message and not an SES indicator??? C1281 will generate a Service Vehicle Soon message but not a Service Engine Soon message.
Here is the Theory of Op for the SWPS/EBTCM and what conditions set the code:
DTC C1281 Steering Sensor Uncorrelated Malfunction Without RPO JL4
Circuit Description
The EBTCM uses four inputs from the Steering Wheel Position sensor:
Phase A digital input
Phase B digital input
Index pulse
Analog input
This information is used to calculate three things:
The front wheels position when centered.
The front wheels position when turning.
The vehicles lateral acceleration.
The EBTCM runs a centering routine when the vehicle speed goes above 30 Km/h (18 mph). When the vehicle reaches 30 Km/h (18 mph), the EBTCM monitors the Steering Wheel Position Sensor inputs (Phase A, Phase B and Analog voltage) to see if the steering wheel is moving. If the steering wheel is not moving for a set period of time then the EBTCM assumes the vehicle is going in a straight line. At this point, the EBTCM looks at the analog voltage signal and reads the voltage. This voltage normally around 2.5V, is then considered the center position and the digital degrees also become zero at the same time. This centering routine is necessary to compensate for wear in the steering and suspension. Wear in the steering and suspension can result in a change in the relationship between the steering wheel and the front wheels. By running the centering routine the EBTCM can compensate for these changes by changing the digital and analog center position.
The EBTCM uses the digital input (Phase A and Phase B) from the Steering Wheel Position Sensor to calculate the direction the driver of the vehicle is trying to steer during an ABS event. This information is also used to calculate the vehicles lateral acceleration for Magnasteer®2.
Conditions for Setting the DTC
DTC C1281 will set when the digitally derived centered angle differs from the analog derived angle by 27 degrees or more for a period of 5 seconds.
DTC C1281 will set if the index pulse is not seen between ± 37 degrees or is seen between -185 degrees and -37 degrees or 37 degrees and 185 degrees of steering wheel travel.
DTC C1281 will set if phase A and or phase B are shorted.
Action Taken When the DTC Sets
Magnasteer®2 is disabled, ABS/TCS remains active.
Messages displayed on the DIC:
Service Vehicle Soon
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
If the analog Steering Wheel Position Sensor input is missing then DTC C1288 will set.
If the Steering Wheel Position Sensor 5 volt supply or the Steering Wheel Position ground is missing DTC C1288 will set.
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.
Here is the Theory of Op for the SWPS/EBTCM and what conditions set the code:
DTC C1281 Steering Sensor Uncorrelated Malfunction Without RPO JL4
Circuit Description
The EBTCM uses four inputs from the Steering Wheel Position sensor:
Phase A digital input
Phase B digital input
Index pulse
Analog input
This information is used to calculate three things:
The front wheels position when centered.
The front wheels position when turning.
The vehicles lateral acceleration.
The EBTCM runs a centering routine when the vehicle speed goes above 30 Km/h (18 mph). When the vehicle reaches 30 Km/h (18 mph), the EBTCM monitors the Steering Wheel Position Sensor inputs (Phase A, Phase B and Analog voltage) to see if the steering wheel is moving. If the steering wheel is not moving for a set period of time then the EBTCM assumes the vehicle is going in a straight line. At this point, the EBTCM looks at the analog voltage signal and reads the voltage. This voltage normally around 2.5V, is then considered the center position and the digital degrees also become zero at the same time. This centering routine is necessary to compensate for wear in the steering and suspension. Wear in the steering and suspension can result in a change in the relationship between the steering wheel and the front wheels. By running the centering routine the EBTCM can compensate for these changes by changing the digital and analog center position.
The EBTCM uses the digital input (Phase A and Phase B) from the Steering Wheel Position Sensor to calculate the direction the driver of the vehicle is trying to steer during an ABS event. This information is also used to calculate the vehicles lateral acceleration for Magnasteer®2.
Conditions for Setting the DTC
DTC C1281 will set when the digitally derived centered angle differs from the analog derived angle by 27 degrees or more for a period of 5 seconds.
DTC C1281 will set if the index pulse is not seen between ± 37 degrees or is seen between -185 degrees and -37 degrees or 37 degrees and 185 degrees of steering wheel travel.
DTC C1281 will set if phase A and or phase B are shorted.
Action Taken When the DTC Sets
Magnasteer®2 is disabled, ABS/TCS remains active.
Messages displayed on the DIC:
Service Vehicle Soon
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
If the analog Steering Wheel Position Sensor input is missing then DTC C1288 will set.
If the Steering Wheel Position Sensor 5 volt supply or the Steering Wheel Position ground is missing DTC C1288 will set.
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.
Thread Starter
Instructor
Joined: Jul 2011
Posts: 198
Likes: 0
From: Hemet California
Just to make sure, you are getting a Service Vehicle Soon message and not an SES indicator??? C1281 will generate a Service Vehicle Soon message but not a Service Engine Soon message.
Here is the Theory of Op for the SWPS/EBTCM and what conditions set the code:
DTC C1281 Steering Sensor Uncorrelated Malfunction Without RPO JL4
Circuit Description
The EBTCM uses four inputs from the Steering Wheel Position sensor:
Phase A digital input
Phase B digital input
Index pulse
Analog input
This information is used to calculate three things:
The front wheels position when centered.
The front wheels position when turning.
The vehicles lateral acceleration.
The EBTCM runs a centering routine when the vehicle speed goes above 30 Km/h (18 mph). When the vehicle reaches 30 Km/h (18 mph), the EBTCM monitors the Steering Wheel Position Sensor inputs (Phase A, Phase B and Analog voltage) to see if the steering wheel is moving. If the steering wheel is not moving for a set period of time then the EBTCM assumes the vehicle is going in a straight line. At this point, the EBTCM looks at the analog voltage signal and reads the voltage. This voltage normally around 2.5V, is then considered the center position and the digital degrees also become zero at the same time. This centering routine is necessary to compensate for wear in the steering and suspension. Wear in the steering and suspension can result in a change in the relationship between the steering wheel and the front wheels. By running the centering routine the EBTCM can compensate for these changes by changing the digital and analog center position.
The EBTCM uses the digital input (Phase A and Phase B) from the Steering Wheel Position Sensor to calculate the direction the driver of the vehicle is trying to steer during an ABS event. This information is also used to calculate the vehicles lateral acceleration for Magnasteer®2.
Conditions for Setting the DTC
DTC C1281 will set when the digitally derived centered angle differs from the analog derived angle by 27 degrees or more for a period of 5 seconds.
DTC C1281 will set if the index pulse is not seen between ± 37 degrees or is seen between -185 degrees and -37 degrees or 37 degrees and 185 degrees of steering wheel travel.
DTC C1281 will set if phase A and or phase B are shorted.
Action Taken When the DTC Sets
Magnasteer®2 is disabled, ABS/TCS remains active.
Messages displayed on the DIC:
Service Vehicle Soon
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
If the analog Steering Wheel Position Sensor input is missing then DTC C1288 will set.
If the Steering Wheel Position Sensor 5 volt supply or the Steering Wheel Position ground is missing DTC C1288 will set.
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.
Here is the Theory of Op for the SWPS/EBTCM and what conditions set the code:
DTC C1281 Steering Sensor Uncorrelated Malfunction Without RPO JL4
Circuit Description
The EBTCM uses four inputs from the Steering Wheel Position sensor:
Phase A digital input
Phase B digital input
Index pulse
Analog input
This information is used to calculate three things:
The front wheels position when centered.
The front wheels position when turning.
The vehicles lateral acceleration.
The EBTCM runs a centering routine when the vehicle speed goes above 30 Km/h (18 mph). When the vehicle reaches 30 Km/h (18 mph), the EBTCM monitors the Steering Wheel Position Sensor inputs (Phase A, Phase B and Analog voltage) to see if the steering wheel is moving. If the steering wheel is not moving for a set period of time then the EBTCM assumes the vehicle is going in a straight line. At this point, the EBTCM looks at the analog voltage signal and reads the voltage. This voltage normally around 2.5V, is then considered the center position and the digital degrees also become zero at the same time. This centering routine is necessary to compensate for wear in the steering and suspension. Wear in the steering and suspension can result in a change in the relationship between the steering wheel and the front wheels. By running the centering routine the EBTCM can compensate for these changes by changing the digital and analog center position.
The EBTCM uses the digital input (Phase A and Phase B) from the Steering Wheel Position Sensor to calculate the direction the driver of the vehicle is trying to steer during an ABS event. This information is also used to calculate the vehicles lateral acceleration for Magnasteer®2.
Conditions for Setting the DTC
DTC C1281 will set when the digitally derived centered angle differs from the analog derived angle by 27 degrees or more for a period of 5 seconds.
DTC C1281 will set if the index pulse is not seen between ± 37 degrees or is seen between -185 degrees and -37 degrees or 37 degrees and 185 degrees of steering wheel travel.
DTC C1281 will set if phase A and or phase B are shorted.
Action Taken When the DTC Sets
Magnasteer®2 is disabled, ABS/TCS remains active.
Messages displayed on the DIC:
Service Vehicle Soon
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
If the analog Steering Wheel Position Sensor input is missing then DTC C1288 will set.
If the Steering Wheel Position Sensor 5 volt supply or the Steering Wheel Position ground is missing DTC C1288 will set.
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.
That helped quite a lot. When you say Magnasteer is disabled, what exactly do you mean? Not the power steering, right? And call me stupid, but what exactly is involved with checking the grounds? Or would it just be better to take it to chevy?
