Diagnostic article Generic OBD-II
P0864: Touareg transmission communication is outside its expected behavior
Volkswagen P0864 directs diagnosis to the CAN wiring and participating components in the BKW Touareg system.
Read before applying this article
Documented application
2004 Volkswagen Touareg (7LA), V10 5.0L diesel BKW; original diagnostic chart and component procedure; confirm installed transmission where relevant.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
Volkswagen's P0864 chart describes transmission-controller communication range/performance and directs correction of faults in CAN wires or other CAN components. It does not identify the TCM as the only possible failed part.
The network includes two engine controllers
The BKW component procedure identifies engine controllers J623 and J624 for the two cylinder banks. Its termination checks are performed on the appropriate isolated controller using specified test-box adapters. The documented 115–135-ohm ranges apply to those individual test arrangements.
They are not a universal resistance target for a fully connected vehicle diagnostic connector. Measuring a network in a different configuration and comparing it with the isolated-controller value could create a false failure conclusion.
Wiring remains a separate branch
When the controller termination checks are within range, Volkswagen directs investigation of the data-bus wiring or other components. A correct resistor result establishes only that part of the network assessment; it does not prove every message is being exchanged correctly.
The code chart supplies no specific message timeout or low-voltage threshold for P0864. It should not be silently rewritten as a total loss-of-communication code or a fixed electrical-low fault.
Verification should establish intact physical communication paths and correct information exchange among the relevant controllers, using the actual vehicle configuration. The source's test prerequisites include ignition off for the resistance assessment. Module replacement should follow the supported branch rather than the generic appearance of “TCM” in the code title.
Source and applicability
Volkswagen diagnostic chart, P0864. 2004 Volkswagen Touareg (7LA), V10 5.0L diesel BKW; original diagnostic chart and component procedure; confirm installed transmission where relevant. These values describe that documented monitor; they are not universal specifications for every vehicle displaying this code.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
TCM Communication Circuit Range/Performance
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT