Dodge R1500 1999 Service Manual page 166

Fig. 3: Locating Data Link Connector (DLC) (Ram Van & Ram Wagon)
Courtesy of Courtesy of Chrysler Corp.
IDLE SPEED & MIXTURE
Idle speed and mixture are controlled by Powertrain Control
Module (PCM). No adjustment is required. PCM controls Idle Air Control
(IAC) motor for proper idle speed. See SELF-DIAGNOSTICS - JEEP, TRUCKS
& RWD VANS article for diagnosis of incorrect idle speed or IAC motor
operation.
THROTTLE BODY MINIMUM AIRFLOW
NOTE: Throttle body minimum airflow procedure checks throttle body
calibration for correct idle speed. Procedure may be used for
idle speed problems caused by the throttle body. Throttle
body minimum airflow procedure should be performed after all
other diagnostic procedures have failed to produce results
that indicate a throttle body related problem. Ensure IAC
motor is operating correctly before performing this
procedure.
Dakota, Durango, Ram Pickup, Ram Van & Ram Wagon
1) Start engine and warm engine to normal operating
temperature. Ensure all accessories are off. Shut engine off. Remove
air duct at throttle body.