CAN bus trouble code?
U0002: Code U0002 indicates the CAN High bus has a performance problem.
How does a CAN bus work?
The CAN bus system enables each ECU to communicate with all other ECUs – without complex dedicated wiring. Specifically, an ECU can prepare and broadcast information (e.g. sensor data) via the CAN bus (consisting of two wires, CAN low and CAN high).
Where is the CAN bus located?
Typical places to pick up CAN include the ABS system (look for a pair of twisted wires, but ignore the four wheel speed wires) or on the back of the dashboard (look for a pair of twisted wires). If the vehicle does have CAN Bus on the OBD connector, it will normally be on Pins 6 and 14 as indicated below.
CAN High CAN Low?
The wires are called CAN high and CAN low. When the CAN bus is in idle mode, both lines carry 2.5V. When data bits are being transmitted, the CAN high line goes to 3.75V and the CAN low drops to 1.25V, thereby generating a 2.5V differential between the lines.
What should CAN bus voltage be?
Measuring Voltage with a Multimeter Value should normally be in between 2.5 and 3.5 Volts. Measured on a machine that is running, it will usually range between 2.7 and 3.3 Volts. Value should normally be in between 1.5 and 2.5 Volts.
Is there a fault code reader for the CAN bus?
There are many fault code readers on the market that can tell you that there is a problem with the CAN Bus, but these tools are limited, in that they do not give you a true indication of where the fault really lies. This tool tells more than the typical fault code reader without the complication of complex analysis software.
How can I tell if my CAN bus is at fault?
Now we will explore how you can look at what is in the CAN frames with the use of a Windows-based analyser tool. There are many fault code readers on the market that can tell you that there is a problem with the CAN Bus, but these tools are limited, in that they do not give you a true indication of where the fault really lies.
Why is my CANbus error code still working?
In 95% of cases, this will be enough to overcome the issue. However some vehicles can be particularly fussy and they still throw up an error. The issue is with the amount of resistance that would be needed for it to match a filament bulb. It would simply be too big and be too hot. The heat from a resistor would cause it to fail almost instantly.
How to diagnose communication problems in a CANbus?
Below are some tips for diagnosing CANBUS communication problems: There must be exactly two (2) termination resistors of 120 ohms each at the physical ends of the CANBUS.