Valtra E002 – Engine Control Unit (ECU) / EEM3: Difference Between Positive and Negative Characteristic is Out of Range

The Engine Control Unit (ECU) has detected that the difference between the positive and negative signal characteristics of the dual-potentiometer hand throttle sensor is outside the acceptable range. The two signals are designed to be inverse of each other; if they go out of sync, the ECU logs this fault to prevent unintended acceleration or erratic engine behavior.

• F Series
• T Series
• N Series
• 6000 Series
• 8000 Series

1. 1

   Visually inspect the hand throttle lever, the sensor itself, and all associated wiring for any signs of physical damage, corrosion, or loose connections

2. 2

   Disconnect and inspect the hand throttle sensor's electrical connector for bent pins, corrosion, or moisture. Clean the contacts with electrical contact cleaner if necessary and ensure a secure connection when reassembled

3. 3

   Check the wiring harness leading from the sensor to the ECU for any chafing, breaks, or short circuits

4. 4

   Verify that the sensor is receiving the correct reference voltage from the ECU (approximately 5 volts) using a multimeter

5. 5

   Check if the throttle sensor can be recalibrated using the tractor's onboard diagnostic tools or a dealer service tool

1. 1

   Perform resistance test (Power Off)

   Disconnect the tractor's battery and unplug the sensor's electrical connector. Measure the total resistance between the two outer terminals (should be constant). Connect one probe to the center (wiper) terminal and the other to one of the outer terminals, then slowly move the hand throttle lever from minimum to maximum; resistance should change smoothly. Repeat the test between the wiper and the other outer terminal.

2. 2

   Perform voltage test (Power On)

   With the sensor connected and ignition on (engine off), back-probe the signal wire at the sensor's connector. Connect the multimeter's positive lead to the signal wire and negative lead to a good chassis ground. Slowly move the hand throttle from idle to full; voltage should sweep smoothly (approx. 0.5V to 4.5V). Repeat for the second signal wire, which should sweep in the opposite direction (4.5V to 0.5V).

3. 3

   Replace hand throttle sensor

   Ensure the tractor is off and the battery is disconnected. Disconnect the electrical connector, remove the mounting hardware, and install the new sensor in the correct orientation. Secure with mounting hardware, then reconnect the electrical connector and the battery.

4. 4

   Calibrate new sensor

   After replacement, a calibration of the new sensor may be required. Refer to the tractor's service or operator's manual for the specific procedure.