Subsection 01 (DIAGNOSTIC AND FAULT CODES)
GENERAL GUIDELINES TO SOLVE FAULT CODES
CONDITION
ACTION
Low system voltage
on one module.
Power problem on sensor(s)
Check related fuse(s) and relay.
Check related power and ground wires.
Check for common power supply to several sensors/modules
(refer to
POWER DISTRIBUTION AND GROUNDS)
.
NOTE:
Some sensors are supplied by the battery while others are
supplied by a module.
Low system voltage
on several modules
(several communication faults
will also appear)
Check battery condition and connections.
Check related fuse(s) and relay.
Check voltage regulator/rectifier.
High system voltage on several
modules
A battery charger has likely been used to substitute the vehicle battery.
Clear all occurred faults and check again.
Check voltage regulator/rectifier.
When all modules report that a
module is missing
Check the module that is reported as missing.
Check related fuse(s) and relay.
Check related power and ground wires.
When several modules are in fault
Search for a common problem such as a faulty sensor.
CAN bus OFF
When several modules and sensors report that a module is missing.
The missing module may report CAN bus off.
Check related CAN wires (continuity, short to
ground, short between CAN low and high).
Check module pins and wiring terminals.
Then, the other modules should stop reporting that module is missing.
May have been generated due to a system or component that was
momentarily operating outside normal parameters.
May be generated when disconnecting and reconnecting a component,
replacing a burnt fuse, or may be due to a momentary high or low voltage.
Occurred fault(s)
Before being "Occurred", a fault has always been "Active"
for a certain time, indicating that an unexpected condition
or problem has been present during the driving cycle.
A frequent momentarily fault or an intermittent fault may never
be seen as "Active" in B.U.D.S. while there is still a pending problem.
This type of malfunctions can be discovered by looking at
the "Occurred" faults and then by evaluating the fault count.
As long as a fault is present, it is displayed as "Active".
Fault count
(0 - 255)
Low value:
Suggests handling problems
(connections, terminal contact/shape etc.).
High value:
Suggests a frequent and unsolved problem.
The problem should be investigated.
Fault conditions
(more details button)
Look for abnormal, excessive values.
Hard to find problems
When the basic troubleshooting has been done and the fault
code(s) persists, often the problem is related to the wiring
harness, connections or electromechanical components.
Short to ground, to battery or between wires.
Wire splices, chafing, terminal problems
(pulled out, bent, out of shape, corroded etc.).
Bad contacts in switch or relay.
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