2011 x5 35d with 10 Fault Codes
 

The wife came home the other day with an Engine malfunction, reduced power message. Pulled the codes and there were 16 present at the time. We've known for a while that we have a faulty upstream NOX sensor. I've spoken to at least 15 specialty shops in 2 different provinces and can't find a single one willing to tackle an SCR/DPF/EGR delete. So I'm at the point I'm just going to change the sensor. But there's more issues as well here.

Cleared the codes and checked them again today and 10 codes came back.

4BDC - Fuel Vorfoerderdruckregelung performance fuel pump too low for
current delivery pump
4BDA - Fuel Vorfoerderdruckregelung performance fuel pump too low for current delivery pump
4BF5 - Too long invalid NOx sensor upstream of the DeNOx catalyst NOx signal
4BC2 - Air flow meter signal
4831 - Intake air temperature sensor
4BC6 - Intake frequency to low
A559 - Shutdown (Instrument Cluster)
9E77 - Normalize Error (SEATS)
A6D1 - Short circuit to positive or open circuit - additional water pump (Junction Box Passenger)
AA11 - Unknown Fault (Flexible-Bus Interface)

Wondering if any experts out there can help diagnose what I need to order for parts.

Problem with ignoring CELs and codes is that it can make diagnoses so much more difficult.

The MAF sensor also should include an intake air temp sensor inside it... all wires/connections/harnesses good?

With all those somewhat unrelated codes, I'm wondering if you could have a general battery/voltage problem.

Cleaning the MAF is on my list of things to do this weekend. Hopefully that takes care of those 2. It's nice to know the IAT is inside the MAF

Interesting thought. It's been sitting for a few months while I searched for someone willing to tackle the deletes. The battery did fully die and we put a trickle charger on it for a good 48hrs before starting it up. It threw 16 codes which I then cleared to see which actually came back.

There is a high pitched whine noise coming from the tank area though which says to me there's definitely something related to the fuel pump going on which the code would back up.

But I have to wonder if maybe some of those others are still battery related

A dirt maf will NOT also cause an IAT issue....

The commonality is the wires on the maf itself...so a bad connection or rodent damage would cause both errors.

Speaking of...any signs of rodents nesting?

No signs of rodent nesting under the hood, but there are rats in the neighborhood which doesn't mean one didn't chew at some wiring while scavenging for nesting materials. I'll add that on my list for this weekend.

Wiring harness is pristine, no signs of any rodent damage. I'll still clean the MAF and connector this weekend. I'll also put the battery on a good charger and clear the codes again and see what comes back.

Alright, slowly making progress at this. Trying to get everything buttoned up before it goes under the knife for the delete next month.

So far I've put in a new 105amp hour battery which took care of:
A559 - Shutdown (Instrument Cluster)
9E77 - Normalize Error (SEATS)
AA11 - Unknown Fault (Flexible-Bus Interface)

New right side fuel pump and fuel filter. That took care of:
4BDC - Fuel Vorfoerderdruckregelung performance fuel pump too low for
current delivery pump
4BDA - Fuel Vorfoerderdruckregelung performance fuel pump too low for current delivery pump

New Bosch MAF sensor. That took care of:
4BC2 - Air flow meter signal
4831 - Intake air temperature sensor
4BC6 - Intake frequency to low

Still left (with the addition of 1 new code):
4BF5 - Too long invalid NOx sensor upstream of the DeNOx catalyst NOx signal
A6D1 - Short circuit to positive or open circuit - additional water pump (Junction Box Passenger)
4A44 - Glow plug cylinder 3, control

4BF5 will be coded out with the delete.

A6D1 has me scratching my head. As far as I know, the 2011's don't have an aux water pump. Where is this pump actually located so I can go check to see if it's there?

4A44 just showed up yesterday, doesn't trip the CEL or seem to be affecting startup in any way but still going to have to get this one fixed.

I got a6d1 too... It's a pump that runs to heat at idle. Despite the code for a year, I can hear the pump working and heat works well. Don't worry about it, it's a hassle to get to by the drivers side front, near the intercooler hose but half way into the plastic partition.

Glue plug cel could be the gp or the gp controller. I have one that came up recently for 5, will do it when it gets warmer.