Jeff5886

When I am driving my truck the throttle seems very very touchy, and when all of the sudden stop responding. I have a guage for the throttle pos sensor and when this happens it will read zero. I can push the pedal in and nothing will happen for about 5-6 pumps and then all of the sudden, back to normal for about 10 miles. ***...

Throws a check engine code of p0121.......

Please help, I am transfering duty stations to Camp Lejeune tommorow!!!

BigIron70

ACCELERATOR PEDAL POSITION SENSOR (APPS) - ECM INPUT
DESCRIPTION
The APPS assembly is located at the top-left-front of the engine APPS Assembly Location A plastic cover is used to cover the assembly. The actual sensor is located behind its mounting bracket APPS Sensor Location (Rear View)

OPERATION
The Accelerator Pedal Position Sensor (APPS) is a linear potentiometer. It provides the Engine Control Module (ECM) with a DC voltage signal proportional to the angle, or position of the accelerator pedal. In previous model years, this part was known as the Throttle Position Sensor (TPS)

Diesel engines used in previous model years used a mechanical cable between the accelerator pedal and the TPS lever. Linkage and bellcranks between the TPS cable lever and the fuel injection pump were also used. Although the cable has been retained with the APPS, the linkage and bellcranks between the cable lever and the fuel injection pump are no longer used.

The APPS is serviced (replaced) as one assembly including the lever, brackets and sensor. The APPS is calibrated and permanently positioned to its mounting bracket.

CAUTION: Do not attempt to remove sensor from its mounting bracket as electronic calibration will be destroyed (sensor-to-bracket mounting screws are permanently attached) Two accelerator lever set screws APPS Assembly Location are used to position lever. Do not attempt to alter positions of these set screws as electronic calibration will be destroyed.
ACCELERATOR PEDAL POSITION SENSOR (APPS)
The APPS is serviced (replaced) as one assembly including the lever, brackets and sensor. The APPS is calibrated to its mounting bracket. The APPS assembly is located at left-front of engine below plastic cable/lever/linkage cover Cable/Lever/Linkage/Cover

CAUTION: Do not attempt to remove sensor from its mounting bracket as electronic calibration will be destroyed (sensor-to-bracket mounting screws are permanently attached) Two accelerator lever set screws APPS Assembly are used to position lever. Do not attempt to alter positions of these set screws as electronic calibration will be destroyed

REMOVAL
1.Disconnect both negative battery cables at both batteries.
2.Remove cable cover Cable/Lever/Linkage/Cover Cable cover is attached with 2 Phillips screws, 2 plastic retention clips and 2 push tabs Cable/Lever/Linkage/Cover Remove 2 Phillips screws and carefully pry out 2 retention clips. After clip removal, push rearward on front tab, and upward on lower tab for cover removal.
3.Using finger pressure only, disconnect end of speed control servo cable from throttle lever pin by pulling forward on connector while holding lever rearward Cables at Throttle Lever DO NOT try to pull connector off perpendicular to lever pin. Connector will be broken.
4.Using two small screwdrivers, pry throttle cable connector socket from throttle lever ball Cables at Throttle Lever Be very careful not to bend throttle lever arm.
5.Disconnect transmission control cable at lever arm (if equipped) Refer to Group 21, Transmission.
6.Squeeze pinch tabs on speed control cable Cables at Throttle Lever and pull cable rearward to remove from cable mounting bracket.
7.Squeeze pinch tabs on throttle cable Cables at Throttle Lever and pull cable rearward to remove from cable mounting bracket.
8.If equipped with an automatic transmission, refer to Group 21, Transmission for transmission control cable removal procedures.
9.Disconnect wiring harness clip APPS Assembly at bottom of bracket.
10.Remove 6 mounting bolts APPS Assembly and partially remove APPS assembly from engine. After assembly is partially removed, disconnect electrical connector from bottom of sensor by pushing on connector tab Electrical Connector at Bottom of APPS
11.Remove APPS assembly from engine.
INSTALLATION
1.Snap electrical connector into bottom of sensor.
2.Position APPS assembly to engine and install 6 bolts. Tighten bolts to 12 N·m (105 in. lbs.) torque.
3.Connect wiring harness clip APPS Assembly at bottom of bracket.
4.If equipped with an automatic transmission, refer to Group 21, Transmission for transmission control cable installation procedures.
5.Install speed control cable into mounting bracket. Be sure pinch tabs Cables at Throttle Lever have secured cable.
6.Install throttle cable into mounting bracket. Be sure pinch tabs Cables at Throttle Lever have secured cable.
7.Connect throttle cable at lever (snaps on)
8.Connect speed control cable to lever by pushing cable connector rearward onto lever pin while holding lever forward.
9.Install cable cover.
10.Connect both negative battery cables to both batteries.
11.ECM Calibration: Turn key to ON position. Without starting engine, slowly press throttle pedal to floor and then slowly release. This step must be done (one time) to ensure accelerator pedal position sensor calibration has been learned by ECM. If not done, possible DTC's may be set.
12.Use DRB scan tool to erase any DTC's from ECM/PCM.

XJJoe01

If you have to replace the APS, do a search for timbo's replacement sensor. I recently replaced mine from Timbo and truck works like a charm.

Joe