System Diagnosis - Revised Diagnostic Charts and Schematics

This article has been updated with bulletin No. 83-90-08.


NEW TOOL J 42958, REVISED CHARTS AND SCHEMATICS FOR CRUISE CONTROL DIAGNOSIS

ELECTRO-MOTOR (STEPPER MOTOR) CRUISE CONTROL SYSTEMS
A new Cruise Control Tester, J 42958 must be used for this diagnosis. This tool will work on all Stepper Motor Cruise Control systems for past model years.

WIRING DIAGRAMS









DIAGNOSIS





















The charts and schematics in this bulletin can be used in place of the diagnostic charts in previous Service Manuals when this new tool is used.

CRUISE CONTROL INOPERATIVE

IMPORTANT
To avoid misdiagnosis:
^ Check for proper operation of brake lamps.
^ Check throttle linkage for mechanical binding which could cause the system to malfunction
^ Check for stored Diagnostic Trouble Codes (DTCs) in the PCM.

THE PCM WILL INHIBIT CRUISE CONTROL:
^ When vehicle speed is less than 40 km/h (25 mph).
^ When PARK, REVERSE, NEUTRAL, or 1st gear is indicated by the Park/Neutral Position Switch,
^ When an over/undercharged battery condition exists.
^ With low engine RPM.
^ With high engine RPM (fuel cut-off).