Not Using J 42958 Cruise Control Tester

Diagnostic Chart (Part 1 of 4):

Diagnostic Chart (Part 2 of 4):

Diagnostic Chart (Part 3 of 4):

Diagnostic Chart (Part 4 of 4):

DIAGNOSTIC AIDS

IMPORTANT: Perform the following in order to avoid misdiagnosis:
^ Inspect for proper operation of the brake lamps.
^ Inspect the throttle linkage for mechanical binding which could cause the system to malfunction.
^ Inspect the cruise control adjustment for minimum slack.
^ inspect for stored Diagnostic Trouble Codes DTC's in the PCM. Refer to A Powertrain On Board Diagnostic (OBD) System Check in Computers and Control Systems.
^ EMI on the speed sensor signal circuit may cause erratic cruise control operation.

ALTERNATIVE DIAGNOSIS
The J 42958 Cruise Control Tester may be used if desired. See Service Bulletin 8-90-08A or refer to Cruise Control inoperative/Malfunctioning Using J 42958 Cruise Control Tester

CONDITIONS FOR ENABLING CRUISE CONTROL
^ The vehicle speed is more than 40 km/h (25 mph)
^ PARK, REVERSE, NEUTRAL, or 1st gear IS NOT indicated by the Park / Neutral Position Switch.
^ An over undercharged battery condition DOES NOT exist.
^ Normal engine RPM is present.
^ High engine RPM (fuel cut-off) is not present. Refer to Fuel Metering Modes of Operation in Powertrain Management.