The 1999 Dodge Ram 3500 was offered with either single or dual rear wheels, and with several engine and transmission options.The throttle position sensor for the 5.9 liter engine provides throttle position data.This information is used to assist the powertrain control module in precise engine and transmission management. A faulty TPS can set several PCM codes: P0121 -- TPS does not collaborate with the MAP sensor; P0122 -- TPS low voltage; and P0123 -- TPS high voltage.
Remove the air intake tube from the throttle body with a screw driver. Locate the throttle position sensor on the driver side of the throttle body. Disconnect the connector. Use caution when depressing the connector lock. It has been exposed to extreme heat and can become brittle and break. Unscrew the TPS mounting bolts, using the torx socket and 1/4-inch-drive ratchet. Rotate the sensor clockwise and pull it from the throttle body.
Slide the new TPS onto the throttle shaft, aligned a few degrees to the right of the final mounting position. Rotate the sensor counterclockwise until the mounting holes line up with the mounting holes on the throttle body. Insert the bolts and torque them to 60 inch-pounds using the torque wrench. Operate the throttle by hand several times to check for any binding in the TPS.
Reconnect the electrical connector to the TPS. Install the air intake tube to the throttle body and secure it. Connect the code reader to the diagnostic connector and clear the codes from the powertrain control module. Start the engine and observe the check engine light.
