[beegeezy]

OK, I could use some help. I finished replacing my water pump, radiator, thermostat, drive belt/pulley/tensioner, transmission pan/filter, and mechatronic sleeve on Monday. I took the car for a post-repair test drive and everything was great. I went out to drive the car to work this morning and it wouldn’t start. I had a bunch of error messages pop up on the dash and infotainment screen...transmission malfunction, brake system failure, etc. I put the car on the battery charger and tried again when I got home. The car started and moved, but the same errors showed up almost immediately. I scanned the car with my BimmerLink app and got this list of codes:

Error memory
Date: 6/8/21, 4:38 PM
VIN: WBAFR7C55DC818132

10 Central gateway module
2 errors
CD040A: FaCanBusOff
801C20: Central fault memory full

12 Motor electronics
1 error
CD840A: FA-CAN Control Module Bus OFF

18 Transmission control
5 errors
CF0403: CAN: (FA-CAN) communication error
CF19C1: Message group error 3 (effect while driving: none) Message missing, receiver EGS (FA-CAN), transmitter Kombi (FA-CAN)
CF20C1: Message group error 3 (effect while driving: none) Message missing, receiver EGS (FA-CAN), sender CAS / FEM / JBBF / FRMFA (FA-CAN)
CF18E1: Message group error 3 (effect while driving: none) Message missing, receiver EGS (FA-CAN), transmitter ICM (FA-CAN)
CF16D1: Message group error 3 (effect while driving: none) Message missing, receiver EGS (FA-CAN), transmitter DSC (FA-CAN)

20 Tyre pressure control 1

1 error
D11403: Message (drive train data, 0x3F9) missing, RDC receiver (K-CAN), DME1 transmitter (FlexRay)

29 Dynamic stability control MK60 E5
1 error
4809C1: EMF takeover not possible

40 Car access system
1 error
D91410: DME CAN message data drive train: Missing or CRC error

5E Gear selector switch
1 error
E09400: Message (data display gear train, 0x3FD) missing, receiver GWS (PT-CAN), transmitter EGS (PT-CAN)

60 Instrument panel
6 errors
E11460: Message (data display gear train, 0x3FD) missing, receiver KOMBI, sender EGS DKG
E11462: Message (data display gear train, 0x3FD) not current, receiver KOMBI, sender EGS DKG
E11465: CAN communication error E1040A: FA-CAN Control Module Bus OFF
2

B7F68B: KOMBI: gear position, switching point display switched off (implementation error)
B7F68C: COMBI: Error in gear position, shift point display, CAN messages (detection by graphic board)
3


Lots of CAN errors, but where to start? I have ISTA+ if that helps instead of BimmerLink.

Also, during my repairs, the car slipped off the jack and I broke two of the 3 bolts that mount the EPS motor to the rack. I removed the motor, used an easy-out on the broken bolts, replaced the EPS motor, and did the steering wheel end stop teach procedure with ista to center the steering wheel. All of which worked perfectly during my test drive.

I was thinking it might be a bad battery but it’s only about 18 months old and seems to holding a charge.

Any ideas?

[beegeezy]

More potential things to check.... the car was parked outside (under car port) with the hood open for quite a while (3-4 weeks). And I know we have rats in the area.

[Unspec]

Originally Posted by beegeezy

More potential things to check.... the car was parked outside (under car port) with the hood open for quite a while (3-4 weeks). And I know we have rats in the area.

I hate to say it, but...check your wiring. Hope for the best.

[beegeezy]

Originally Posted by Unspec

I hate to say it, but...check your wiring. Hope for the best.

Thanks. I did a quick look over in the engine bay after removing as many plastic covers as easily possible. I don’t see any obvious damage at least.

[beegeezy]

I'm still trying to figure this out.

The last thing I did after parking the car was install my daughter's car seat. I pulled the seat bottom and sides out this morning to check for pinched wires...no luck.

I also had the battery tested at NAPA. It was down to ~20ish percent charged, but showed good amperage. I assume some modules were not shutting down and it discharged the battery. I have recharged it now.

I used my fluke multimeter to test the parasitic drain. I saw 4 amps for a few minutes, then ~900 milliamps for another few minutes, then down to 30-40 milliamps, which should be fine.

I'm still studying the wiring diagrams for common can or flexray circuits to try to pinpoint this as much as possible.

[Sylverlee]

A battery that is dying could throw a bunch of random codes. I've had it happen. It was after not coding my battery to the right AH.

[beegeezy]

Originally Posted by Sylverlee

A battery that is dying could throw a bunch of random codes. I've had it happen. It was after not coding my battery to the right AH.

I can try testing it again. The battery was my initial thought, but it isn't acting like a bad battery. And it seems to charge fine.

[beegeezy]

Battery tested good. Back to square one.

[chipguy]

I would double check the mechantronic sleeve. If the connector to the transmission is not seated properly, you could easily have these errors. Of course, you should also check the wiring just to be sure.

[beegeezy]

Originally Posted by chipguy

I would double check the mechantronic sleeve. If the connector to the transmission is not seated properly, you could easily have these errors. Of course, you should also check the wiring just to be sure.

I hope it’s not that...the access sucked even with the RWD. It’s worth checking though. The car drove fine and then this happened the next morning...which makes me think it’s not a loose plug or damaged wire, but rather a battery or bad module issue. However, I don’t want to rule anything out yet.

[chipguy]

There are multiple CAN buses on the car. It seems to be complaining about the FA-CAN bus. What would be helpful is look at the map on ISTA and figure out which modules the FA-CAN goes to, following the wiring and check the connectors. I would go through the wiring carefully since you have rats near your car.

[beegeezy]

Originally Posted by chipguy

There are multiple CAN buses on the car. It seems to be complaining about the FA-CAN bus. What would be helpful is look at the map on ISTA and figure out which modules the FA-CAN goes to, following the wiring and check the connectors. I would go through the wiring carefully since you have rats near your car.

It would help if I knew to what FA-CAN was referring. I don't see FA-CAN in any of the wiring diagrams.

[beegeezy]

This is from newTIS:

Bus systems

Bus system analysis
The electronic control units in the vehicle are connected to one another via a network. In this system network, the central gateway module plays a decisive role. The central gateway module is responsible for ensuring that information is transferred from one bus system to another bus system.

The engine control and suspension control system are linked via the PT‐CAN (or PT‐CAN2) and FlexRay bus systems to the central gateway module. The control units of the general vehicle electrical system are connected via the K‐CAN and the K‐CAN2.

For most control units in the area of information and communication systems, MOST is available as an information service. The vehicle diagnosis communicates via D‐CAN. The vehicle is programmed/encoded via the Ethernet access. The overall network consists of various bus systems that ensure communication between the individual control units.

Overview of the bus systems

In principle, two groups of bus systems are distinguished:

‐> Main bus systems: Ethernet, FlexRay, K‐CAN, K‐CAN2, MOST, PT‐CAN and PT‐CAN2

‐> Sub‐bus systems: BSD, D‐CAN (diagnosis-on-CAN), LIN, local CAN

Body CAN: Body CAN

The K‐CAN is responsible for communication of the components with low data transfer rates. The K-CAN is also linked to the other bus systems via the central gateway module (ZGM). A number of control units in the K‐CAN have a LIN bus as sub‐bus. The K‐CAN has a data transfer rate of 100 kBit/s and consists of 2 twisted cores (two twisted wires). The K‐CAN has the possibility to be operated as a single-wire bus in the event of errors.

Body CAN2: K‐CAN2

The K‐CAN2 is responsible for communication of the control units with high data transfer rates. The K-CAN2 is also linked with the other bus systems via the central gateway module (ZGM). A LIN bus is connected as sub‐bus on all control units in the K‐CAN2. The K‐CAN2 has a data transfer rate of 500 kBit/s and consists of 2 twisted cores.

Powertrain CAN: PT-CAN

The PT‐CAN connects the engine control system with the transmission control unit, but also interconnects systems in the area of safety and driver assistance systems. It is line-based with tap lines to the individual systems. The PT‐CAN has a data transfer rate of 500 kBit/s and consists of 2 twisted cores.

Powertrain CAN2: PT-CAN2

The PT‐CAN2 forms a redundancy for the PT‐CAN in the area of the engine control system and also transfers signals to the fuel pump control module. The PT‐CAN2 has a data transfer rate of 500 kBit/s and consists of 2 cores with an additional wake-up line.

Ethernet

Ethernet is a manufacturer-neutral, cable-based network technology with a data transfer rate of 100 MBit/s. The TCP/IP (Transmission Control Protocol/Internet Protocol) and UDP (User Datagram Protocol) reports are used as transfer reports.

FlexRay

With a maximum data transfer rate of 10 MBit/s per channel, FlexRay is significantly faster than the data buses used so far in vehicles in the areas of body and drive/chassis and suspension. The central gateway module sets up the link between the various bus systems and the FlexRay. Depending on the equipment fitted in the vehicle, the ZGM has one or two so-called star couplers, each with four bus drivers. The bus drivers forward the data of the control units via the communication controller to the central gateway module. The deterministic data interchange ensures that each message is transferred in the time-controlled section in real time. Real time means that the transmission takes place in a specified time.

MOST bus system

MOST is a data bus technology for multimedia applications. The MOST bus uses light impulses for the data transfer at a rate of 22.5 MBit/s and has a ring structure. Data transfer on the ring bus takes place in one direction only. Only the central gateway module can implement data exchange between the MOST bus and other bus systems. The car information computer (CIC) acts as the master control unit The gateway to the rest of the bus system is the central gateway module.

Possible faults in bus systems
The following fault causes can lead to bus faults:

Short circuit of a bus line
Interruption of a bus line
Fault in a gateway
Fault in the transmitter or receiver of a control unit

[beegeezy]

Update:

Bonus points to chipguy. The problem was the mechatronic sleeve not seating properly. It was fully installed into the case, but the receiving side on the trans computer will allow you to lock the sleeve in place with it fully seated AND roughly 1/8” removed! So, it looks to be installed, but the pins don’t make a solid connection. I had to pull the valve body to learn what what going on.