U0162 - Lost communication with Navigation Display Module
System
Network & Communication (CAN-bus)
Technical Description
The control module has detected a fault in the Data Bus Communication (Navigation Display Module) (U0162). Node involved: the "Navigation Display Module". Carried over the vehicle data bus. Communication with the module has dropped out entirely — the controller no longer receives any frames from it on the data bus.
Multimeter Test Points & Nominal Values
| Test Point / Component | Measurement | Nominal Target Range | Test Condition |
|---|---|---|---|
| Check for "the "Navigation Display Module"" (U0162) (Action ()) | Mätning | Measure ignition supply and ground right at the module connector, then check CAN continuity from the module pins back to the gateway. | Vehicle data bus |
| CAN Termination (OBD pin 6 ↔ 14) | Resistance (Ω) | 60 Ω (two 120 Ω in parallel) | Battery disconnected, ignition OFF |
| CAN-H / CAN-L Bias Voltage | Voltage (V) | CAN-H ≈ 2.5 - 3.5 V, CAN-L ≈ 1.5 - 2.5 V (recessive ≈ 2.5 V both) | Ignition ON, bus active |
| Navigation Display Module – Power and Ground | Voltage (V) | Supply 11.8 - 14.4 V / ground drop < 0.1 V | At module connector under load |
Vehicle data bus
Battery disconnected, ignition OFF
Ignition ON, bus active
At module connector under load
Oscilloscope Waveform Analysis
10 µs/div, 1 V/divPossible Causes
The module has lost power or ground, or the bus stub feeding it is broken
Bus segment:look up topology, speed and termination in the wiring diagram.
Check the two termination resistors (120 Ω each) — a broken or removed terminator produces reflections and the same fault class.
A chafed, pinched or heat-damaged section of the twisted bus pair — the segment often passes a sharp edge or hot surface.
A single babbling node with a faulty bus transceiver can drag the whole segment into the same fault state.
Symptoms
4
Recommended Solution
Measure ignition supply and ground right at the module connector, then check CAN continuity from the module pins back to the gateway.
Measure bus resistance across CAN-H/CAN-L, ignition off: 60 Ω normal, ~120 Ω = a terminator/branch missing, <10 Ω = conductor-to-conductor short.
Scope CAN-H and CAN-L together, ignition on, and judge whether the fault is an open (one trace flat), a short (traces collapsed together) or impedance (ringing).
Halve the segment:disconnect half the bus at a central splice and re-measure — the fault is in the half where the reading does not return to normal.
Disconnect modules on the segment one at a time; if the bus recovers when one particular module is unplugged, that node transceiver is the disturbance.
Mechanic's Tip
If several modules drop together the fault is on the backbone or gateway; if only this one drops, the fault is local to the module.