Sensor Signal Faults (Trace) - WABASH COMMUNICATIONS MBS-1P Installation Manual

MBS-1P Installation

Sensor Signal Faults (Trace)

While the trailer is moving, the MBS-1P continually compares the wheel speed
signals from each sensor. If a wheel speed signal becomes inadequate, a
sensor signal fault is detected. The malfunction lamp illuminates and the fault
code is stored in memory. However, the fault detection mechanism is different
from other faults because a bad signal fault is only detected when the trailer is
moving. All other faults are electrical in nature and are detected at power up.
Because of this difference, sensor signal faults result in slightly different
malfunction lamp behavior. The concept of a fault "trace" helps explain how the
malfunction lamp functions. A fault trace is between a current fault and a
stored fault.
NOTE: The concept of a fault trace only applies to sensor signal faults.
On the next stationary power up after a sensor signal fault is detected, the
malfunction lamp remains ON due to the presence of a fault trace, providing
an indication of a malfunction. A flash code read for current faults will indicate
the appropriate sensor signal fault.
Figure 22, Trace Sensor Signal Codes
36
• A current fault represents an existing fault condition. It causes the ABS
malfunction lamp to be illuminated and disables trailer ABS.
• A stored fault is a record of a previous fault that no longer exists. It has no
affect on normal malfunction lamp operation or ABS function.
• A fault trace is a temporary record of an earlier fault that slightly modifies
malfunction lamp operation but does not affect ABS function. It normally
clears itself within about two minutes of normal driving if the signal is
okay.
Function of Sensor Signal Fault Codes (Trace)
Current Faults
• Illuminate the ABS
malfunction light
• Disable trailer ABS
• Cannot be cleared
• Become stored faults
after repair.
Trace Faults
• Sensor faults only
• Set temporary code
• Can clear themselves
• Do not disable ABS
• Become Stored faults
after clearing themselves.
®
Stored Faults
• Were originally current
or trace faults
• Do not illuminate the
ABS malfunction light
• Do not disable ABS
• Stored codes can
be cleared.
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