Key Fob + TMP Failure

[Wilsonized]

Hi, my car battery recently was drained by the water pump not shutting off and after I recharged the car battery I got "TPM failure" and "Keyfob Not Detected." I replaced coin batteries in both key fobs to no avail. I replaced the radio receiver in the PS trunk area with matching numbers to no avail. Every time the car battery dies these gremlins show up and I'm usually able to fix them, but this is the first one I can't fix. Car battery appears normal, holds charge, no warnings, is registered. They key fobs are properly paired/programmed as the both start the car using RFID. The fobs are only detected by the radio receiver for keyless entry SOMETIMES, usually after sitting overnight then completely randomly after that. The buttons on the fob NEVER work. I end up having to manually lock the car which as you can imagine is a pain in the ass. I don't know ISTA well enough, but I do have it. Any clues would be great. I have already looked at other forums, leads. Seems there are a few others with no solution as well.

[stocktree]

I'd start with the main battery. Low voltage can cause lots of issues. And when you replaced the coin batteries, did you make sure there wasn't a sticker on one side of them that you had to remove?

[74Marcin]

I had same problem my keyfobs and comfort access stop working plus TPMS malfunction but after disconnecting and connecting plug from radio receiver everything starts working again

[Wilsonized]

I just replaced the main battery and registered it. Still no dice. coin batteries have no plastic.

[Wilsonized]

Originally Posted by 74Marcin

I had same problem my keyfobs and comfort access stop working plus TPMS malfunction but after disconnecting and connecting plug from radio receiver everything starts working again

I tried unplugging it as well, when that didn't work, I replaced it entireley - still didn't work.

[Wilsonized]

Originally Posted by stocktree

I'd start with the main battery. Low voltage can cause lots of issues. And when you replaced the coin batteries, did you make sure there wasn't a sticker on one side of them that you had to remove?

Drove it around for a day after replacing/registering the battery and the key fobs and TPMS are back! New main battery fixed it. Thank you.

[stocktree]

Originally Posted by Wilsonized

Drove it around for a day after replacing/registering the battery and the key fobs and TPMS are back! New main battery fixed it. Thank you.

That's good to hear. When voltage gets low, the power module shuts down non critical modules, to save power.

[aschmidt]

In ISTA+ what acceptable voltage I always caution when it shows high or low than expected.