The car’s various systems are not working. This comprises the electrical functions of instruments, door locks, wipers, and other body parts. This may also be accompanied by the “Electronic Malfunction” check control message and instrument cluster warning lamps.
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When I tried to start my 2005 E60 yesterday, I received an Electronic System Malfunction notice. Since the wipers were turning on, it was simple to determine that the cruise control and windshield wipers were inoperable based on the messages from the car controls.
I obtained a number of codes, several of which indicated CAS:K-CAN line faults or communication faults. The battery is roughly a year old, although the alternator is much older, and I’ve read that these problems can be caused by the battery/alternator. Read the BCM/KBM as well; that might be the problem.
I was unsure of where to begin my investigation into the issue, but I can post all the codes if that’s helpful.
K-CAN Line issue on a BMW E704
E704 IHKA: K-CAN line fault is associated with a CAN line issue. E72D is a constant trouble code without a message ( control valve in the air conditioning compressor, 0x2DE) integrated automatic heating/cooling system receiver, JBE transmitter, E71E no message (torque 0x0AA), receiver IHKA, and DME-DDE transmitter. The error code E704 IHKA: K-CAN line fault is shown when the Junction box electronic control module (JBE) detects an incorrect or absent signal from the rear HVAC controller. It’s quite conceivable that the air conditioning system won’t work if this failure code is stored in JBE.
BMW uses a two-wire K-CAN line system to connect a number of control modules, including the junction box electronic (JBE), the instrument cluster meter, the tire pressure control module (TPMS), the airbag control module, the ride height control module (EHC), and the climate control module (IHKA). Every control module may store a fault code as a result of K-CAN line failure.
BMW’s sporadic K-CAN error codes
In my first grab, CH C reveals the green wire K-CAN signal is sporadically toggling above ground at the HVAC module and CH D is the yellow K-CAN wire at the HVAC. This BMW sets intermittent K-CAN codes in roughly 10 modules. The radio receives the same K-CAN signals.
The wire harness under the driver-side carpet has a lot of white corrosion that was brought on by water incursion, but there are no evidence of water in the trunk.
Someone provided me with a decent K-CAN waveform, and in the final capture, the lower voltage ought to be flat at 884 mv rather than wavering.
Here is one way to describe K-CAN:
- Oscilloscope use for K-CAN diagnosis Low and high patterns. The High and Low Square Waves have to be in perfect harmony. Volt meters are merely a temporary fix and not a permanent solution.
Consider looking at SI B61 18 14, in my opinion. This is a typical issue and an excellent place to start.
In order to prevent confusion among individuals who are unfamiliar with BMW, I believe it is vital to mention. “K CAN” is merely a CAN Bus in name; it doesn’t adhere to the CAN Bus conventions that are usually accepted. In essence, it consists of two single wire K lines, one of which has been reversed. Terminating resistors have no established standards and can have values as high as 800 ohms.
Only when the issues are K-Bus2 related does that bulletin apply. I need to have read the post’s specifics more carefully!
BMW Coding K-Line Cable Interface
BMW automobiles with the K-line interface from 1996–2007 can be accessed with the K-Line cable, a diagnostic USB device. It is a standalone programming tool that instantly establishes a connection with your car and cooperates with the BMW diagnostic software of your choice. All BMW diagnostic software (native to Windows and Android) is supported by the cable, including INPA, ISTA, Rheingold, EDIABAS, NCS Expert, DIS, Progman, Carly for BMW, and others.