TCS Code

[Parker]

A few weeks back, I had an odd sensation in the brake pedal of my 1997 Eldorado ETC one morning. I bought the car new, and it now has about 75,000 well maintained miles. When coming to a stop, there was sort of a vibration in the brake pedal along with an odd buzzing sound sort of like ABS engagement but different. This lasted only a second or two, and happened maybe three times that morning. When parking, I ran the DIC for codes and had the following two set:

TCS C1223 History and TCS C1224 History

These translate as follows according to the diagnostic manual:

C1223 - Left Rear Wheel Speed Sensor Input Signal is 0

C1224 - Right Rear Wheel Speed Sensor Input Signal is 0

This has happened two more times in the last six weeks or so, the most recent time just this morning. The last two times this happened, no codes were set, and the codes that were set initially are now gone. Don't know how they got erased. I didn't erase them. The sensation and sound only last a second or so, and don't seem to have any effect on braking. It only happens at low speed, such as when coming to a red light, or slowing to park.

Just wondering if this is likely a sensor or something simple (inexpensive) to have repaired, or is some expensive piece of hardware beginning to fail. I just don't want to stroll into my dealer asking them to check it out not having any idea what to expect. If anyone has any tips or suggestions, or has experienced this on their Caillac, any input would be appreciated.

Thanks to all,

Regards,

Rich

[jhall]

Rich,

It's very unlikely that both sensors would fail simultaneously. Before you head down the path of parts replacement, check a couple of items:

Has anyone worked near the front end lately - e.g. tire change, brake check, etc? It's pretty easy to bump the connectors loose on some caddy's. Confirm that the connectors are locked into place.

If nobody has worked on the front end, the other possiblity is a bad ground connection. Pull the connection off the battery and look carefully at the terminals and battery cables. Make sure you look inside the rubber boots on the terminals to make sure ALL of the parts are free from corrosion. Also, check the ground connection at the other end of the battery cable.

Good luck! Keep us posted!

[Parker]

With the exception of oil changes, no one has touched the car lately. THe code faults related to the rear wheel speed sensors, why would the front end be involved?

The codes are no longer set. Would this indicate there is no existing fault?

[jhall]

Parker,

Ooops - had a brain drain on the post. Sorry.

Check the ground leads and make sure these are OK. Again, it's not likely both sensors failed at the same time. Usually a faulty ground will cause the type of problem you described.

I don't know if a '97 Eldo has a ground lead carried to the rear of the car or if it's mostly the body that is used as the ground return. Hopefully some other forum members can provide info.

[coolnesss]

I've been getting a C1287 code intermittently - the traction control comes on for a few seconds on otherwise clean dry pavement. Its happend 3 times in the past month or so, then reverts to normal.

I can't access the old board's archives - so am mystified as to what is the problem.

[WarrenJ]

The codes are no longer set. Would this indicate there is no existing fault?

Codes are automatically "flushed" if they do not recur after a certain number of ignition cycles. The code won't resurface until the PCM senses that fault again.

Regards,

Warren