I installed a P-81ACRD in my car a while ago and had no problems until lately when I started using the Bluetooth music function. My car was using the factory Hands Free Link for the cellphone but used the Power Acoustik Bluetooth 2.1 music sync (so I could listen to music off my phone without taking it out of my pocket). Parked, the car was fine and music played like normal (because TPMS is not active while stopped) but when driving for some reason there was little but noticeable interference (music would so silent for a split second). I had it hooked up to Bluetooth but played music off my I-pod because there was no interference. About 20 miles into my first drive my TPMS malfunction light lit up and both rear TPMS sensors were fine but read an error code that signal interference has occurred ( code 31 and 34). I had to bring the car to Honda and they reset the light for an arm and a leg considering they didn't do anything except reset the light and drive my car . Apparently what I have found out is that the Honda TPMS uses Bluetooth signals and the Power Acoustik P-81ACRD both interfere with each other setting off the light. I'm not 100% sure but this may also apply with other Bluetooth devices.

 

Aftermarket electrical devices can interfere (e.g., inverter, battery chargers, CB radios, etc.) with the radio frequency signal from the sensor when driving. However, in general, most Bluetooth devices don't interfere with Honda's TPMS.

Are you sure it was DTC 31? DTC code 31 would be a tire pressure sensor low voltage for tire pressure sensor number 1. If this was the case, then it may be due to the TPMS sensor battery or a faulty sensor.

DTC 32, 34, 36, and 38 are for tire pressure sensor signal failure.

I haven't really heard of people having TPMS signal failure problems associated with some of the aftermarket Navi system they installed.

 

Sorry for making that confusing, I had both 31 and 34 they cleared both looking at the first repair bill. Later my stupid phone decided it would connect to the P-81ACRD (I didn't delete the P-81ACRD from my phone) the and sure enough the TPMS light came back on, I talked to the tech that fixed it the second time and he said that it was probably the Bluetooth. I just got it all fixed and everything is fine now after 30+ miles but I'm assuming its the Bluetooth because the 31 code didn't come back up on the second repair bill (they waived the fee). You could be right though I'm just hoping that the TPMS doesn't come up again I hate going to the dealer.