Update on Peake 18/ 2A "hardwire" code
Bringing this back up because I am getting the 2A code.
I recently replaced the RF wheel sensor and had the ABS module replaced under warranty by BBA. No other symptoms other than "tirecontrol inactive". which usually takes a few minutes to show.
So today I ran it down to my trusted indy and he ran some scans. It turns out that at around 20 mph, the scanner loses connection with the car OBD II port! His scanner shows wheel speeds on each wheel and I went for a ride. At 10 mph indicated, the numbers stop scrolling up, and a couple of seconds later, the scanner loses its connection. It is Bluetooth, but given the receiver is about 2 feet away for the plugged in module, it is pretty unlikely a ($15,000) scanner issue.
Now it could be an ABS module issue, but since it has recently been replaced by BBA under warranty and I am not seeing any other codes, I think that unlikely.
I am attaching a picture of the sine wave of each wheel (I believe the bottom axis is miliseconds, but I am not sure). The vertical axis is speed in mph.
I am also attaching a voltage graph. Seems that there is a downward spike each time the sine wave is measured. It pulls almost a whole volt, which to my electrically amateurish brain is way too much. So is the "hardwire "code have something to do with an electrical error, such as the alternator or voltage regulator malfunctioning? Again, NO OTHER CODES. It appears when the connection drops out, the code shows up. "Hardwire" sounds like either the ABS module or the RKW module behind the glove box is loosing communication.
One other thought from my indy. The RF wheel sensor replacement may have not been BMW OE, and it is possible a slight difference in spec is creating the different sine wave; enough to trip the code, but not enough to set off a check engine light.
He also thought that a non standard wheel bearing on that side could affect the reading, ( the 'reluctor"?) but no wheel bearing change recently. No apparent wheel bearing issues either.
So, the error code seems to be a loss of communication, or electrical issue causing the loss of communication (the voltage downward spike is 11.7, perhaps low enough for the momentary loss of communication?). Maybe with the additional information, we can finally figure this out. I am reluctant to start throwing parts at this, although I do have a spare RDW module courtesy of Clemster.
Regards,
Jerry
Oh, we disconnected each sensor and gave the inside connectors a quick clean and reconnected.