[SwaggyP]

Hello All,

Need your help/ advice. I own a 2011 335d, 47k miles, 2 months remaining on manufacture warranty, running JBD @ 100% for the past 3-4 months.

On my way to work today my SES light turned on. Symptoms were very low power and low fuel economy. Once I arrived to work and parked I pulled out my BMWhatt app and read the codes w/ my Wifi Dongle. The app pulled the following two Motor Ecu codes:

1. BMW Code 004674 - injection quantity monitoring quantity error correction over range

(I've had this code pop-up multiple times but I thought it was a tuner code/shadow code)

2. BMW Code 004600 - Rail Pressure too low / positive control deviation


My First question is... is the 004674 code related to the JBD modifying the fuel injection quantity? If so, should I reset the codes, remove the JBD and wait for the 004600 code to populate again? Once it does bring drive it straight to the dealer.

My second question is why would the rail pressure be too low? from my understanding the JBD increases rail pressure and it should be the exact opposite reading. Did the JBD burn out the fuel pump? Did I cause a leak in the fuel injectors?


Background information:

On June 3rd I was driving the car extremely hard and the check engine light turned on. This was the first time I had the digital "valve looking" check engine light turn on rather than the standard SES light. The check engine that I am referring to illuminated where the low fuel symbol usually is. I'm not sure what the difference is?

I figured this was the check engine light everyone talks about when using the JBD unit. When I turned the car off and back on the check engine symbol was gone and the car drove fine. Before I turned off the car I read the following codes:

1) BMW Code 004674 - injection quantity monitoring quantity error correction over range


2) BMW Code 003EED - Unknown Failure

3) BMW Code 004C4F - Rail Pressure Control Valve

4) BMW Code 00429A - TCU low - pressure stage error

5) BMW Code 00480A - Particle Filter System

I know I shouldn't have erased the codes but I honestly thought it was the JBD causing a bunch of false readings. I was driving the car extremely hard. I figured if the codes populated again without driving the car hard I would bring it into the dealer.

Whats everyones thoughts? Sorry for the long post!

[SwaggyP]

Anyone's opinion is greatly appreciated!

[Hoooper]

The jbd tricks the computer into thinking the rail pressure is lower than it is, so the computer cranks up the pressure. If the code is because of the jbd, that's why.

[DWR]

The 2 codes are related. Reason is exactly as Hoooper said.

[gtp900]

I have been told that the fuel rail pressure sensor can be damaged from the JBD, as it raises rail psi as others here have said,( tricks ecu to see lower rail psi) and thus raises psi, damaging sensor.

[iaknown]

Do like you said......pull the JBD, reset, and see what happens.