I have the following 28 TCS DIC code errors:

C1221H LF Wheel Speed Sensor Input Signal is 0
C1222H RF Wheel Speed Sensor Input Signal is 0
C1255H EBTCM Internal Malfunction
C1281H Stearing Sensor Uncorrelated Malfunction

What does all this mean in laymens terms??? I have previously cleared these codes and it seems that after 100 miles the "Service Vehicle Soon" light chimes and appears on display. I cleared it like a dimwit before taking it in to dealership. They of course found nothing wrong.

If I do not clear the errors, the message does not come on. When cleared, as stated above, after 100 miles of driiving, "Service Vehicle Soon" message appears and these four codes are in the DIC.

No other codes present.

I have not noticed any problems with the wheels or steering wheel. Any idea's?

I hate to do it, but think I'll need to take it back to dealership......

HELP!!!!

 

Could be a bad wheel speed sensor but with all of the other codes set, it looks like you may have a bad or confused EBCM (Electronic Brake Control Module). There are other conditions that can set these like intermittent and poor wheel speed sensor/EBCM/etc. connectors and bad wheel bearings. All is conjecture though, without a scan tool. Leave the codes and get to the dealer with the "Service Engine Soon" lit up and let a tech make a proper diagnosis.

Don't assume the worst as it will probably be something simple (I hope :) ). :cheers:

 

Sven,
I take it your car is a 98. Here is some information I scanned from the 97 Service Manual. Codes C1221 and C1222 are the same except that they apply to different wheels. I can't get the diagnositic tables into the post but could probably send PDF files containing them.

C1221/C1222:
Circuit Description
The speed sensor used on this vehicle is a single point magnetic pickup. This sensor produces an
AC signal that the EBTCM uses the frequency from to calculate the wheel speed.
Conditions for Setting the DTC
The DTC will set if one wheel speed = 0 and the other WSS are greater than 8 Km/h (5 mph) for 2.5 seconds.
Action Taken When the DTC Sets
A malfunction DTC is stored, ABS/TCS is disabled and the ABS and Traction Control Indicators are turned ON.
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 DTC(s) detected.

Diagnostic Aids
. 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 General Electrical Diagnosis Procedures in Wiring Systems.
Test Description
The numbers below refer to step numbers on the diagnostic table.
3. Checks the resistance of the WSS.
5. Checks if the WSS CKTs are shorted together.

C1255:
Circuit Description
This DTC identifies a malfunction within the EBTCM. Conditions for Setting the DTC
DTC C1255xx is set when an internal EBTCM malfunction exists.
Action Taken When the DTC Sets
A malfunction DTC is stored, ABSfTCS is disabled and the ABS and Traction Control Indicators are turned ON.
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
DTC(s) detected.
Diagnostic Aids
. When DTC C1255xx is displayed on the Scan Tool, it will be followed by two more numbers which should be noted along with any other DTCs that may be displayed. The additional
two numbers displayed with DTC C1255xx are for aiding engineering to determine the cause of the internal malfunction.
. Make sure the integrity of the connection between the EBTCM and the BPMV is secure, tight, and free from corrosion.
C1281:
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: 1. The front wheels position when centered. 2. The front wheels position when turning.
3. The rate at which the steering wheel is turning. 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 tires when driving in a straight line. 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 rate at which the steering wheel is turning to control the amount of effort required from the driver to turn the steering wheel using Magna Steer@.

Conditions for Setting the DTC
. DTC C1281 will set when the digitally derived centered angle differs from the analog derived angle by 27. or more for a period of 5 seconds.
. DTC C1281 will set if the index pulse is not seen between ::t 37. or is seen between -185. and -37. or 37. and 185. of steering wheel travel.
. DTC C1281 will set if phase A and or phase B are shorted.

Action Taken When the DTC Sets
. Magna Steer@ is disabled, ABS/TCS remains active.

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 DTC(s) 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
General Electrical Diagnosis Procedures in Wiring Systems.
Test Description
The numbers below refer to step numbers on the diagnostic table.
3. Checks for the analog voltage to change, if tI analog voltage does not change DTC C1281 will set.
4. Checks if the digital Phase A and Phase B a changing state from high to low.
5. checks to see if the analog and digital readin are :t 27' of each other.
31. Checks to see if the EBTCM is supplying the pull up voltage for Phase A.
32. Checks to see if the EBTCM is supplying the pull up voltage for Phase B.
33. Checks to see if the EBTCM is supplying the Dull UD voltaae for the Index pulse.

Hope this info helps in some way.
Bill


[Modified by Bill Dearborn, 7:58 PM 1/4/2003]

 

W :eek: W! That's alot of info. that flew right over my head! :lol:

Appreciate the info., seriously. Hopefully I can get Speed Demon to check it when I take the car in week after next. I'd hate to take to the $tealership....2 bad experiences already :mad