For some background. I have been having problems with my 98 Coupes key less & manual entry setting off the cars alarm when opening either side door.
The RF receiver functioned fine with the TPMS wheel transmitters. I did have major problems with the key fobs staying paired to the car. Sometimes they worked sometimes they didn't. It almost seemed like the system was falling asleep and was unresponsive to the key fobs.

Key fobs are both new and the correct model. I just finished installing a new/used RF TPMS/Keyless entry receiver today. Now the fobs are working fine. Lock and unlock functions for doors and hatch are fine. The one major issue that remains is when I unlock either door and open it the alarm horn and flashing lights come on. I can cancel the alarm by either inserting the key into the ignition or push the lock or unlock button on the key fob. I don't believe it can be the DCM (door control modules) because the alarm is triggered by either the driver or passenger doors. If not mistaken the RDCM and LDCM module are both separate components. For some reason after the key fob has sent the signal to unlock the doors (the doors do unlock) the process of shutting off the horn/lights flashing is incomplete.

Any suggestions appreciated.

 

So Mac 5, this is not any advise about how to fix your problem, but I have a similar problem that is just irritating me.

1998 Conv. When I open the drivers door, the chiming sounds , with the key out of the ignition. I believe this chiming sound is to warn the driver of leaving the keys in the ignition or leaving the headlights on. Both my remotes have the passive on/off slide switch. And they are in the off position. And no matter which way I have the slide switch, I still have the same problem. I have owned the vehicle for about 2-3 months. Only lately has the chiming sound been intermittent, now sounding about 90% of the time. At first I thought it more wiring related. But as I dig deeper, it is starting to sound like a security issue, more specific, the keyless entry. When I get out of my car, I walk into the house and immediately I drop the keys on the shelf in the foyer. This puts the keys about 10-14 feet away from the car, although the garage wall is in between the car and the keys. I started to think that the keyless entry system is activated by the fob, and by leaving them so close to the car, it never gets out of range of the car. So I walked to the rear of my property, about 60+ feet, in hopes the remote is out of range. Then I walked back to the car in hopes the keyless entry would disarm the security system. But the problem still remained, chiming when the drivers door is opened. Never when the passenger door is opened.

So I ordered a remote ( $100 ) with out the keyless entry slide switch. Programmed it into the car tonight. Still same problem.

The times when there is no chiming ( and this is intermittent also ) sound when I open the drivers door is when I am leaving work. I get to park the car at the entrance door where I work, auto shop for Junior and Senior High School students. So the remote doesn't get all that far away, maybe 40-50 feet but there is a thick cinder brick wall separating my keys from the car.

I purchased the 3 book series service manuals, used, and just before I started typing this input, I read the receiver for the keyless is the same for the TPMS. When I purchased the car, the seller was up front with me and indicated the car need 2 TPMS sensors. He purchased 4 of them, aftermarket, and gave them to me when I took possession of the car. I have not installed them yet because I didn't want to install aftermarket TPMS sensors. And I am now seeing the OEM TPMS sensors are about $140 , each. The DIC indicates I have the TPMS issue every time I start the car.

So now I am wondering if I were to correct the TPMS issue by installing the new TPMS sensors and calibrating them, will that take car of my chiming when I open the drivers door?

What do you or anyone else think?

 

If you want to make sure your fob can't communicate with your car use a faraday bag. There are several brands out there.
https://slnt.com/collections/faraday-bags-for-keys

 

Although the key fob and TPMS function work through the same receiver module I don't think the TPMS sensor's are related to your key fob problems.

If you programmed the new key fob, I suspect you used the DIC train key fob process. There is one more additional step after programing the key fob. You need to Sync the key fob to the car. To do this stand by the gas cap door and hold the "lock" and "unlock" buttons simultaneously for about 7-10 seconds, if the process works, you'll hear the horn beep one time. Release the buttons and see if that changes anything.

If you still have those old key fobs (passive system) model, make sure they are disabled and not sending any signal to the receiver (remove the batteries from the old key fobs.) I had one fob sending the lock/unlock signal to the car with the slider in either position.

Another thing I learned about the new key fobs is that the battery can be weak due to it being on the shelf for an extended time. Might want to check the new fobs battery at some point.

As for your chiming sound upon opening the door, I do not have that problem.

 

I had numerous problems with my '99.

I finally gave up and switched to the late C5 system. I swapped the receiver, TPMS, and wheel sensors to the new system. The difference in price between the early and late TPMS made it an economical switch over.

Since going to the late C5 system I have not had any problems and like the change.

Good luck.

 

So QCVette, when you say to the " Late C5 System", do you mean later years? like 2000,2001,2002,2003,2004 ? or what years?
Are the wheel sensors different then the TPMS sensors?

 

The 01-04 cars used a different RFA module and tire sensors. Putting these newer RFA modules in 97-00 C5s became a popular mod when the tire sensors for the older cars became difficult to find and expensive. Though that problem is less prevalent today as there are some affordable aftermarket options for 97-00 compatible tire sensors.