DIAGNOSIS
INTRODUCTION TO ASC DIAGNOSIS
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The active skid control system (ASC) operates
differently from conventional brake systems. These
differences include sounds, sensations, and vehicle
performance that owners and service technicians who
are not familiar with ASC may not be used to.
Some operational characteristics may seem to be
malfunctions, but they are simply signs of normal ASC
operation. When diagnosing the ASC system, keep
these operational characteristics in mind. Inform the
owner of the kind of performance characteristics to
expect from an ASC-equipped vehicle.
ASC DIAGNOSTIC TROUBLE CODE
DETECTION CONDITIONS
ASC diagnostic trouble codes (ASC DTCs) are set
under different conditions, depending on the
malfunction detected. Most ASC DTCs will only be set
during vehicle operation. Some ASC DTCs will also
be set during the ASC self-check immediately after
the engine is started.
When you check if an ASC DTC will be displayed
again after the DTC has been erased, you should
duplicate the ASC DTC set conditions. Depending on
the detection timing and set conditions for the specific
ASC DTC, you must either drive the vehicle or turn the
engine off and restart it. To set the proper conditions
for that DTC again, refer to "ASC DTC SET
CONDITIONS" for each ASC DTC that you are trying
to reset.
ASC DIAGNOSTIC TROUBLESHOOTING STRATEGY
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Use these steps to plan your diagnostic strategy. If
you follow them carefully, you will be sure that you
have exhausted most of the possible ways to find an
ASC fault.
1.
Gather information about the problem from the
customer.
2.
Verify that the condition described by the customer
exists.
3.
Check the vehicle for any ASC DTC.
4.
If you cannot verify the condition and there are no
ASC DTCs, the malfunction is intermittent. Refer to
GROUP 00, How to use Troubleshooting/
Inspection Service Points - How to Cope with
Intermittent Malfunctions P.00-15.
5.
If you can verify the condition but there are no ASC
DTCs, or the system cannot communicate with the
scan tool, check that the basic brake system is
operating properly.
⦆
If the basic brake system is not operating
properly, refer to the GROUP 35A, Basic Brake
System Diagnostic troubleshooting strategy P.
35A-5.
⦆
If the basic brake system is operating properly,
refer to P.35C-160.
6.
If there is an ASC DTC, record the number of the
DTC, then erase the DTC from the memory using
the scan tool.
7.
Recreate the ASC DTC set conditions to see if the
same ASC DTC will set again.
⦆
If the same ASC DTC sets again, perform the
diagnostic procedures for the DTC. Refer to P.
35C-11.
⦆
If you cannot get the same ASC DTC to set again,
the malfunction is intermittent. Refer to GROUP
00, How to use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent
Malfunctions P.00-15.
ACTIVE SKID CONTROL SYSTEM (ASC)
35C-7
DIAGNOSIS