[Twilight1]

Has anyone seen 4BAC ?

[Hoooper]

possibly intake air temp or flow related, the closest codes I can find without it showing up on my scanner are 4BA0 and 4BA1 which are intake air temp signal too high and too low. Other 4B.. codes are airflow sensor related

[Brad335d]

4BAC - P203A

Information saved in
DDE

Fault code
4BAC - P203A

Fault text
DDE: Reducing-agent active-tank fill-level sensor, signal:
Sensor fault

Fault description
Monitoring of active tank level sensor. The diagnostic
trouble code is logged when the physical sensor signal is
between 35 % and 45 %.

Condition for fault identification
none

Condition for fault memory entry
Debounce (2000 ms)

Action in service
Check wires and plug connections.
If wiring and plug connections are OK:
Use the diagnostic system to check the fluid levels.
Replace the active tank.
Fault effect and breakdown warning
-

Driver information
Warning light:
MIL

Service instruction
Measure the resistance levels on the level sensor between
reference (pin 1) and tank level 1-3 (pins 2-4). The tank
must be empty for the measurement.
Nominal value with tank empty: 10 kOhm
Resistance levels in excess of 12 kOhms indicate a defective
fluid-level sensor.

[Brad335d]

Your Welcome

[Twilight1]

Originally Posted by Brad335d

Your Welcome

??

Thank you !

[m9bm]

Sorry to revive this.

I have now thrown an SES light and I pulled the same code:
4BAC.

What was the fix for this and how much did it cost?

[Twilight1]

DEF tank. They good willed it.

[rkundrat]

So, I just also got this SES code, 4BAC. made a service appointment, then a few days later the low DEF warning came on (1000 miles till no start.) Car went in today, they changed the oil, topped off DEF, and reset code. They said the SES was because the fluid was low... I thought 4BAC had to do with a signal error from the level sensor? They did no sensor resistance checking. Could it be just low fluid??

[Hoooper]

Yeah, its not because of low fluid. Thats a different code which doesnt trigger an SES light. It will likely be back. I would complain, point out that they dont know what theyre talking about. At least then if youre close to being out of warranty its on record as NOT being fixed.

If youre already out of warranty, dont worry about it. If you can ignore the light (or reset when it comes up) theres no reason to fix it.

[rkundrat]

Originally Posted by Hoooper

Yeah, its not because of low fluid. Thats a different code which doesnt trigger an SES light. It will likely be back. I would complain, point out that they dont know what theyre talking about. At least then if youre close to being out of warranty its on record as NOT being fixed.

If youre already out of warranty, dont worry about it. If you can ignore the light (or reset when it comes up) theres no reason to fix it.

Thanks, and I'm NOT out of warranty, so obviously want this taken care of before I am!

[rogerdiaz]

Originally Posted by Brad335d

4BAC - P203A

Information saved in
DDE

Fault code
4BAC - P203A

Fault text
DDE: Reducing-agent active-tank fill-level sensor, signal:
Sensor fault

Fault description
Monitoring of active tank level sensor. The diagnostic
trouble code is logged when the physical sensor signal is
between 35 % and 45 %.

Condition for fault identification
none

Condition for fault memory entry
Debounce (2000 ms)

Action in service
Check wires and plug connections.
If wiring and plug connections are OK:
Use the diagnostic system to check the fluid levels.
Replace the active tank.
Fault effect and breakdown warning
-

Driver information
Warning light:
MIL

Service instruction
Measure the resistance levels on the level sensor between
reference (pin 1) and tank level 1-3 (pins 2-4). The tank
must be empty for the measurement.
Nominal value with tank empty: 10 kOhm
Resistance levels in excess of 12 kOhms indicate a defective
fluid-level sensor.

Excellent and thank you. I take it dealers or indys dont bother to follow the service instructions and better to replace everything.

[rogerdiaz]

Originally Posted by m9bm

Sorry to revive this.

I have now thrown an SES light and I pulled the same code:
4BAC.

What was the fix for this and how much did it cost?

Indy wants $2950. Fml

[taibanl]

Originally Posted by rogerdiaz

Indy wants $2950. Fml

Dealer should cover for free.

[335dFan]

Originally Posted by rogerdiaz

Indy wants $2950. Fml

Mine was covered this week under the Federal 70,000 emissions warranty. It would have been covered by my BMW Gold Extended Warranty.

They replaced the active DEF tank. Said it would have been about $2,000 if coming out of my pocket.

[rogerdiaz]

Originally Posted by taibanl

Dealer should cover for free.

I have 148,000 miles. 2011. Fml smh.

[taibanl]

Originally Posted by rogerdiaz

I have 148,000 miles. 2011. Fml smh.

Nicely done. Habe you asked? I think there might be an under the radar campaign in this one. Mine was <70 but i expected pushback on the warranty and got none

[sk72]

Couple of days ago I got CEL with P203A or 004BAC (Reductant Level Sensor Circuit) code. Took it to the dealer and they replaced active tank and hose under warranty (10 years/120k miles).

2012 X5 35D

[ddroze]

I just got this code but my car has 150k..... So the dealer wants bank to replace it... My fluid was low and i deleted the code so im not sure what to do because the code is gone now? Dealer wont replace it outside the federal extension. But the dealer said the lines were new so i wonder if its been replaced before? I bought it at 125k miles. Maybe the guy had it done at 110k and they will cover if i can find the receipts in his old records?

My service rep said to go through my old receipts and if i find one, then call BMW customer service at corporate.

[Yozh]

There is a VW part you can fit. And now Bosch started making a drop in replacement. Further, there are ole ty if used tanks around with all the sensors. I have one. Gathering dust.

[JT8Diesel]

I think I’ve had the same code before. It was fixed by filling the tank. I think the DEF can crystallize on it and foul it.

I had 492C come up a while ago (active tank temp sensor). That code has since been cleared.

I just had 4BAC come back, and I’m around 20,000 km since last DEF fill.

I’ll fill DEF today and hopefully that will clear 4BAC. Then I can Drive Clean (Ontario emissions check), then deactivate EGR again.


Edit: Filled DEF and 4BAC is gone again.