How to Check CAN Bus Resistance
Measuring CAN Bus resistance is one of the fastest ways to identify communication network faults. A simple resistance test can reveal open circuits, short circuits or termination resistor problems inside the CAN system.
Prepare the Vehicle for Resistance Testing
CAN Bus resistance must be checked correctly to avoid false readings and possible module damage.
The network should be completely powered down before measuring resistance between CAN High and CAN Low.
Understand Normal and Abnormal Resistance Values
The resistance value helps determine whether the CAN network is healthy or affected by wiring or module faults.
60 Ohms = Normal Network
A healthy CAN Bus usually measures around 60 ohms between CAN High and CAN Low.
120 Ohms = Missing Terminator
One termination resistor may be disconnected or one side of the network may be open.
0–10 Ohms = Short Circuit
The CAN lines may be shorted together or shorted internally inside a module.
Infinite Resistance = Open Circuit
A broken wire or disconnected connector may interrupt the CAN network completely.
Isolate the Faulty Module or Wiring
If the resistance value is incorrect, the next step is to isolate which module or section of wiring is causing the fault.
Disconnecting modules one at a time helps identify short circuits, open circuits or faulty termination resistors.
Master CAN Bus Diagnostics Step by Step
Learn how to measure CAN Bus resistance, diagnose network faults and isolate communication problems using real workshop techniques.