CAN Troubleshooting Guide
Manual • Doc.-No.: C.3055.21 / Rev. 1.1
CAN-CBX-COM2
Page 46 of 125
If it is lower than 2.0 V or higher than 3.0 V, it is possible that one or more nodes have faulty
transceivers.
For a voltage lower than 2.0 V please check CAN_H and CAN_L conductors for continuity.
To find the node with a faulty transceiver within a network please test the CAN transceiver resistance
(see below) of the nodes.
7.5 CAN Transceiver Resistance Test
CAN transceivers have circuits that control CAN_H and CAN_L. Experience has shown that electrical
damage of the circuits may increase the leakage current in these circuits.
To measure the current leakage through the CAN circuits, please use a resistance measuring device and:
1. Switch off the node and disconnect it from the network (see figure below).
2. Measure the DC resistance between CAN_H and CAN_GND (see figure below).
3. Measure the DC resistance between CAN_L and CAN_GND (see figure below).
The measured resistance has to be about 500 k
s
for each signal. If it is much lower, the CAN
transceiver is probably faulty. Another indication for a faulty transceiver is a very high deviation
between the two measured input resistances (>> 200%).
Figure 23: Simplified diagram of a CAN node
7.6 Support by esd
If you have executed the fault diagnostic steps of this troubleshooting guide and you even can not find
a solution for your problem our support department will be able to assist.
Please contact our support via email at
or by phone +40-511-37298-130.