Powertrain Controls - ECM/PCM

DTC 71 Set/Coast Switch Fault:

Set/Coast Switch Fault:

CIRCUIT DESCRIPTION
The cruise "ON/OFF," "set/coast" and "resume/accel" switches are inputs to the fuel control portion of the Powertrain Control Module (PCM). These inputs allow the PCM to control and hold a requested speed. CKT 84 supplies ignition voltage to the PCM when set/coast is depressed.

DIAGNOSTIC TROUBLE CODE (DTC) 71 WILL SET WHEN
^ Cruise control "ON."
^ Ignition voltage on terminal "BD15" for more than 25.5 seconds.

ACTION TAKEN (PCM will default to)
The PCM will disallow all cruise inputs. Torque Converter Clutch (TCC) shift schedules may be affected.

DTC 71 WILL CLEAR WHEN
The fault condition(s) no longer exist, and the ignition switch is cycled "OFF" then "ON."

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This step determines if the cruise control switch is OK.
2. This step determines if the PCM or switch is at fault.

DIAGNOSTIC AIDS
Check for a set/coast switch stuck in the engage position or CKT 84 shorted to voltage.