I Need Help Dealing withThese Fault Codes Please

[BubbaTree]

My Foxwell scanner continues showing sever codes from my '03 convertible. I've yet to find accurate info about the cause and the fix for either fault, so, if anyone can/will step up to steer me along, I'll surely appreciate the help.
Here's the latest inventory of concerns:
0F Voltage Supply EWS3 Control Module
5 SZM Undervoltage, Seat Heating
16 IHKA Relay, Auxiliary Heater
50 MRS Power Supply - Battery Supply Cable

One separate question that may or may not be related to any of these faults. The car has developed a recent intermittent failure of either one of my 2 new factory remote keys to unlock the doors or trunk. To the subject matter experts, if that unlock issue isn't related to the other faults, disregard the question. I'll deal with that another time.
Thanks to anyone who can offer up any assistance or directions!
Regards,
Steve

[sapote]

Use voltmeter and measure battery voltage before and during engine idling.

[BubbaTree]

Here's what I found: Engine cold and not running: Key Off 12.36v; Key on, position 2, 12.20v; Engine at idle 14.12v - 14.15v.
The battery is 38 months old and the seller has checked and declares it good.
Does any of this info help diagnose the problem?
Thanks!
Steve

[maupineda]

I have had seat heating module codes when battery is low. Your battery maybe failing. This is in a Z4M

[BubbaTree]

I have had seat heating module codes when battery is low. Your battery maybe failing. This is in a Z4M

Thanks for the info. Were you able to repair the problem, or replace the faulty module? Where is the hearing module located, under the seat?
Thanks.

[maupineda]

Thanks for the info. Were you able to repair the problem, or replace the faulty module? Where is the hearing module located, under the seat?
Thanks.

In my case it was fixed with a new battery. My old battery would get too low after a week or so, or 10min of listening to the radio.

[sapote]

Here's what I found: Engine cold and not running: Key Off 12.36v; Key on, position 2, 12.20v; Engine at idle 14.12v - 14.15v.
The battery is 38 months old and the seller has checked and declares it good.
Does any of this info help diagnose the problem?
Thanks!
Steve

Alternator and cables are good, but battery 12.36v is too low. How did you measure the battery voltage? It needs a full charge overnight.

[BubbaTree]

Alternator and cables are good, but battery 12.36v is too low. How did you measure the battery voltage? It needs a full charge overnight.

Charge the battery on the bench or in the car with cables connected? What voltage level am I looking for?
Thanks!

[Zack]

Charge the battery on the bench or in the car with cables connected? What voltage level am I looking for?
Thanks!

A fully charged battery is around 12.6v IIRC 12.2-12.3 is something like 25% charged. Charging on a bench or in the car will yield the same effect.

[sapote]

If using power supply, charge it at constant 6A overnight, then charge it at constant 13.5v for 4 hours. At this point if charging current is more than 0.2A then battery is bad.

Normal battery always has 12.6v minimum after parked overnight.

[BubbaTree]

If using power supply, charge it at constant 6A overnight, then charge it at constant 13.5v for 4 hours. At this point if charging current is more than 0.2A then battery is bad.

Normal battery always has 12.6v minimum after parked overnight.

I don't have access to that kind of equipment, but I used my Schumacher charger set to 2Amp overnight. Today, my multimeter shows 12.8v on the bench. After 1 hour, the voltage reads 12.75v, which seems like a significant drop over 1 hour time.

[Zack]

I don't have access to that kind of equipment, but I used my Schumacher charger set to 2Amp overnight. Today, my multimeter shows 12.8v on the bench. After 1 hour, the voltage reads 12.75v, which seems like a significant drop over 1 hour time.

No that's not a problem at all, you're talking .05v drop is the surface charge dissipating

[BubbaTree]

I don't have access to that kind of equipment, but I used my Schumacher charger set to 2Amp overnight. Today, my multimeter shows 12.8v on the bench. After 1 hour, the voltage reads 12.75v, which seems like a significant drop over 1 hour time.

Looks like the battery is the problem. It's dropped from 12.8v to 12.5v in 2 hours sitting on the bench. I'll replace it today and report any similar problems if any should occur. Thanks for the help, and now to see it those pesky fault codes return.
Thanks, again!
Steve

[sapote]

Looks like the battery is the problem. It's dropped from 12.8v to 12.5v in 2 hours sitting on the bench. I'll replace it today and report any similar problems if any should occur. Thanks for the help, and now to see it those pesky fault codes return.
Thanks, again!
Steve

12.5v says it's a bad battery.

[BubbaTree]

12.5v says it's a bad battery.

Thanks for the help! Do you think a bad battery is the cause of some or all of those fault codes I posted in the beginning? I'm getting a new battery tomorrow and will clear those fault codes and see if they return. I'll post the results either way.
Thanks, again!
Steve