AUTO-CRUISE CONTROL
TSB Revision
ENGINE AND EMISSION CONTROL
17-11
AUTO-CRUISE CONTROL SYSTEM DIAGNOSIS
INTRODUCTION TO AUTO-CRUISE CONTROL SYSTEM DIAGNOSIS
M1172003300251
The auto-cruise control system allows driving without
stepping on the accelerator pedal by setting a ran-
dom speed between 40 km/h (25 mph) and 200 km/h
(124 mph). Problems in this system can be investi-
gated by the following methods.
Auto-cruise control system diagnostic
trouble codes
The auto-cruise control system consists of the
powertrain control module (PCM), control switches
and sensors. The control switches and sensors mon-
itor the state of the vehicle. The PCM controls the
throttle valve opening angle in the throttle body in
accordance with the input signals from the switches
and sensors. If the PCM detects a problem on any of
those components, the PCM estimates where the
problem may be occurring, and will set a diagnostic
trouble code. Diagnostic trouble codes cover the
auto-cruise control switch, stoplight switch and PCM.
AUTO-CRUISE CONTROL SYSTEM DIAGNOSTIC TROUBLESHOOTING STRATEGY
M1172002000279
Use these steps to plan your diagnostic strategy. If
you follow them carefully, you will check most of the
possible causes of an auto-cruise control system
problem.
1. Gather information from the customer.
2. Verify that the condition described by the
customer exists.
3. Check the vehicle for any auto-cruise control
system DTC.
4. If you can verify the condition but no auto-cruise
control system DTCs are set, the malfunction may
be intermittent. Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
− How
to Cope with Intermittent Malfunctions
P.00-6
.
5. If you can verify the condition but there are no
auto-cruise control system DTCs, or the system
cannot communicate with scan tool MB991958
(MUT-III sub assembly), refer to
P.17-55
,
Symptom Chart, and find the fault.
6. If there is an auto-cruise control system DTC,
record the number of the code, then erase the
code from PCM memory using the scan tool
MB991958 (MUT-III sub assembly).
7. Re-create the auto-cruise control system DTC set
conditions to see if the same Auto-cruise Control
System DTC will set again.
• If the same Auto-cruise Control System DTC sets
again, perform the diagnostic procedures for the
set code. Refer to
P.17-15
, Auto-cruise Control
System Diagnostic Trouble Code Chart.