2003 ZO6 Codes
Thread Starter
Heel & Toe
Joined: Oct 2024
Posts: 16
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From: SoCal
2003 ZO6 Codes
Yesterday I purchased a 2003 ZO6. While driving home on interstate five I heard a brief electronic/slight mechanical sound, that sounded to me like it was coming out of the speakers. I was using a plug-in charging/Bluetooth device for my cell phone to use the navigation. The Bluetooth device was set to unavailable channel in my area, but that channel was available in the area where I was so the audio of the navigation would not come out of my speakers. So I had just turned them down. when brief sound started I did not think to look at the drivers information center. This occurred twice. when I got home in my driveway, a message popped up on the drivers information center saying service traction control. I shut the car off and waited a few seconds and started it back up and no more message. I then use the option button and fuel button to bring up the codes. codes were as follows : AO-LDCM U1064 H , A1-RDCM U1064 , 28-TCS C1288 H. Can someone please tell me what these code numbers mean? Any help would be greatly appreciated. Thank you, Jack
Last edited by Captjack24; Jan 31, 2025 at 07:23 PM.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,309
Likes: 3,924
From: Cape Coral, Florida
If you have no electrical or diagnostic experience or equipment like a factory level scan tool best to seek out a diagnostic shop or an auto electric shop in your area...unfortunately it's not a blown fuse....the U codes are communication codes and are "history" so you can erase them for now...the C1288 is also a history one...I'd erase that too and on the next ignition cycle see if it is "Current" before you shut the car off.
Circuit Description
The vehicle stability enhancement system (VSES) is activated by the EBCM calculating the desired yaw rate and comparing it to the actual yaw rate input. The desired yaw rate is calculated from measured steering wheel position, vehicle speed, and lateral acceleration. The difference between the desired yaw rate and actual yaw rate is the yaw rate error, which is a measurement of oversteer or understeer. If the yaw rate error becomes too large, the EBCM will attempt to correct the vehicle's yaw motion by applying differential braking to the left or right front wheel.
The amount of differential braking applied to the left or right front wheel is based on both the yaw rate error and side slip rate error. The side slip rate error is a function of the lateral acceleration minus the product of the yaw rate and vehicle speed. The yaw rate error and side slip rate error are combined to produce the total delta velocity error. When the delta velocity error becomes too large and the VSES system activates, the driver's steering inputs combined with the differential braking will attempt to bring the delta velocity error toward zero.
The VSES activations generally occur during aggressive driving, in the turns or bumpy roads without much use of the accelerator pedal. When braking during VSES activation, the brake pedal will feel different than the ABS pedal pulsation. The brake pedal pulsates at a higher frequency during VSES activation.
The usable output voltage range for the lateral accelerometer and yaw rate sensors is 0.25 - 4.75 volts. The scan tool will report zero lateral acceleration or yaw rate as 2.5 volts with no sensor bias present. The sensor bias compensates for sensor mounting alignment errors, electronic signal errors, temperature changes, and manufacturing differences.
The steering wheel position sensor supplies 2 analog inputs, Phase A and Phase B. to the EBCM. The 2 input signals are approximately 90 degrees out of phase. By interpreting the relationship between the 2 inputs, the EBCM can determine the position of the steering wheel and the direction of steering wheel rotation.
Steer angle centering is the process by which the EBCM calibrates the steering sensor output so that the output reads zero when the steering wheel is centered. Using the yaw rate input, lateral accelerometer input, and wheel speed sensor inputs, the initial steering center position is calculated after driving greater than 10 km/h (6 mph) for more than 10 seconds in a straight line on a level surface.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
C1287
One of the following conditions exists:
- The steering wheel position sensor is synchronized and the steer rate (speed that the steering wheel appears to be turning) is greater than 1100 degrees/second.
- The steer rate is less than 80 degrees/second and the difference in the phase angle between Phase A and Phase B is greater than 20 degrees.
- The 2 steering sensor signals (Phase A and Phase B) do not agree for 1 second. Under this condition, this DTC will set along with DTC C1281.
C1288
One of the following conditions exists:
- Both Phase A and Phase B are greater than 4.9 volts for 1.6 seconds.
- Both Phase A and Phase B are less than 0.2 volts for 1.6 seconds.
- The difference in the changes in Phase A and Phase B is greater than 35.2 degrees for 9.76 milliseconds.
Circuit Description
The vehicle stability enhancement system (VSES) is activated by the EBCM calculating the desired yaw rate and comparing it to the actual yaw rate input. The desired yaw rate is calculated from measured steering wheel position, vehicle speed, and lateral acceleration. The difference between the desired yaw rate and actual yaw rate is the yaw rate error, which is a measurement of oversteer or understeer. If the yaw rate error becomes too large, the EBCM will attempt to correct the vehicle's yaw motion by applying differential braking to the left or right front wheel.
The amount of differential braking applied to the left or right front wheel is based on both the yaw rate error and side slip rate error. The side slip rate error is a function of the lateral acceleration minus the product of the yaw rate and vehicle speed. The yaw rate error and side slip rate error are combined to produce the total delta velocity error. When the delta velocity error becomes too large and the VSES system activates, the driver's steering inputs combined with the differential braking will attempt to bring the delta velocity error toward zero.
The VSES activations generally occur during aggressive driving, in the turns or bumpy roads without much use of the accelerator pedal. When braking during VSES activation, the brake pedal will feel different than the ABS pedal pulsation. The brake pedal pulsates at a higher frequency during VSES activation.
The usable output voltage range for the lateral accelerometer and yaw rate sensors is 0.25 - 4.75 volts. The scan tool will report zero lateral acceleration or yaw rate as 2.5 volts with no sensor bias present. The sensor bias compensates for sensor mounting alignment errors, electronic signal errors, temperature changes, and manufacturing differences.
The steering wheel position sensor supplies 2 analog inputs, Phase A and Phase B. to the EBCM. The 2 input signals are approximately 90 degrees out of phase. By interpreting the relationship between the 2 inputs, the EBCM can determine the position of the steering wheel and the direction of steering wheel rotation.
Steer angle centering is the process by which the EBCM calibrates the steering sensor output so that the output reads zero when the steering wheel is centered. Using the yaw rate input, lateral accelerometer input, and wheel speed sensor inputs, the initial steering center position is calculated after driving greater than 10 km/h (6 mph) for more than 10 seconds in a straight line on a level surface.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
C1287
One of the following conditions exists:
- The steering wheel position sensor is synchronized and the steer rate (speed that the steering wheel appears to be turning) is greater than 1100 degrees/second.
- The steer rate is less than 80 degrees/second and the difference in the phase angle between Phase A and Phase B is greater than 20 degrees.
- The 2 steering sensor signals (Phase A and Phase B) do not agree for 1 second. Under this condition, this DTC will set along with DTC C1281.
C1288
One of the following conditions exists:
- Both Phase A and Phase B are greater than 4.9 volts for 1.6 seconds.
- Both Phase A and Phase B are less than 0.2 volts for 1.6 seconds.
- The difference in the changes in Phase A and Phase B is greater than 35.2 degrees for 9.76 milliseconds.
Last edited by C5 Diag; Jan 31, 2025 at 06:38 PM.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,309
Likes: 3,924
From: Cape Coral, Florida
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,309
Likes: 3,924
From: Cape Coral, Florida
Thread Starter
Heel & Toe
Joined: Oct 2024
Posts: 16
Likes: 0
From: SoCal
I am not sure the sound came from my speakers, because it was so brief, and I had not seen the error codes yet. If the traction control was malfunctioning would it make a sound inside of the cabin?
Thread Starter
Heel & Toe
Joined: Oct 2024
Posts: 16
Likes: 0
From: SoCal
I read that the first two codes are related to the right and left door lock mechanism that gets triggered whenever the battery is disconnected. I cleared all the codes and none of them have returned. thank you for your help.
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