New Holland 133 – ENGINE: Decelerator (STD cab) Position Potentiometer Voltage Is Too High

The Engine Control Module (ECM) has detected a voltage signal from the standard cab decelerator pedal's position sensor (potentiometer) that is above the expected maximum threshold. This typically points to an open circuit, a short to a power source, or a failed sensor. When this fault occurs, the ECM may disregard the decelerator input, potentially causing the throttle position to be set to zero percent as a safety measure, which affects the proper operation of the system.

• T4.75
• T4.80
• T4.85
• T4.90
• T4.95
• T4.100
• T4.105
• T4.110
• T4020
• T4030
• T4040
• T4050
• T4060
• T5.95
• T5.105
• T5.110
• T5.115
• T5.120
• T6.120
• T6.125
• T6.140
• T6.145
• T6.150
• T6.155
• T6.160
• T6.165
• T6.175
• T6.180
• T6010
• T6020
• T6030
• T6040
• T6050
• T6060
• T6070
• T6080
• T6090
• T7.165
• T7.170
• T7.175
• T7.185
• T7.190
• T7.200
• T7.210
• T7.220
• T7.225
• T7.230
• T7.235
• T7.245
• T7.250
• T7.260
• T7030
• T7040
• T7050
• T7060
• TM115
• TM120
• TM125
• TM130
• TM135
• TM140
• TM150
• TM155
• TM165
• TM175
• TM190
• Maxxum
• MXM
• MXU
• Puma

1. 1

   Visually inspect the decelerator pedal assembly, potentiometer sensor, and wiring harness for damage, corrosion, or wires that are frayed, pinched, or broken. Ensure all connectors are securely fastened.

2. 2

   Check for an open circuit in the sensor's return wire to the ECM using a multimeter to test for continuity.

3. 3

   Check for a short to power (5-volt or 12-volt supply) on the signal wire by inspecting the harness for areas where it might be rubbing against other components.

4. 4

   Perform a sensor voltage check with the key on and sensor connected; a functioning pedal should show a smooth voltage change, whereas a fault will stick at the maximum level (e.g., 5 volts).

5. 5

   Verify pedal mechanical and switch adjustment to ensure the linkage is not binding and returns to its resting position correctly. Check that the pedal position reads from 100% when up to 0% when fully depressed in the tractor's diagnostic menu.

1. 1

   Confirm the fault

   Using the tractor's onboard diagnostics, confirm that fault code 133 is active.

2. 2

   Perform Diagnostics

   Execute the diagnostic checks listed above, starting with a thorough visual inspection of the wiring and connectors between the decelerator pedal and the ECM.

3. 3

   Test the potentiometer

   Disconnect the harness from the sensor. Using a multimeter, measure the resistance across the sensor's pins as you slowly operate the pedal. If the resistance is infinite (open) or shows erratic jumps, the potentiometer has likely failed.

4. 4

   Adjust the pedal/sensor (If Applicable)

   If the decelerator pedal has an adjustable stop screw or sensor mounting, set it according to the manufacturer's specifications (usually achieving a specific voltage reading at slow and fast idle positions).

5. 5

   Replace the potentiometer

   If the sensor is confirmed to be faulty, disconnect the electrical connector, unbolt the old potentiometer from its mounting, and install the new one in the same orientation.

6. 6

   Clear Fault Codes

   After the repair is complete, reconnect all components and use the diagnostic tool or dashboard interface to clear all fault codes.

7. 7

   Verify the Repair

   Start the tractor and operate the decelerator pedal to ensure it is functioning correctly and that the fault code does not reappear.