New Holland ENG 3046 – Engine Control Module (ECM): Vehicle Speed Sensing - Signal Not Plausible

The Engine Control Module (ECM) is receiving a vehicle speed signal that does not make logical sense when compared to other operating parameters (such as engine RPM, selected gear, or wheel speed sensor data over the J1939 CAN bus). The ECM recognizes that the vehicle is moving, but the speed data being reported by the sensor is erratic, drifting, or mathematically impossible given the current engine and transmission state.

• New Holland T7 Series
• New Holland T8.xxx Series
• New Holland CR9090
• New Holland CX8080 Elevation
• New Holland CX8090 Elevation

1. 1

   Visual Wiring Inspection: Check the vehicle speed sensor circuit for signs of tampering, such as extra wires spliced into the harness, cut braiding, or signs of unnecessary sensor removal.

2. 2

   Pin and Connector Check: Inspect the wiring of the associated pins (e.g., Pin 3/13 on the ECM/sensor harness) for corrosion, moisture, or loose connections that could cause signal drift.

3. 3

   CAN Bus Communication: Check the J1939 data link connection to the Wheel-Based Vehicle Speed Sensor. Verify that the parameters for the Vehicle Speed Sensor source (CCVS1, CCVS2, or CCVS3) are available and not missing.

4. 4

   Check for Related Codes: Look for accompanying codes that might indicate a hard electrical failure rather than just a plausibility issue, such as ENG 3043 (Hardware Conversion Error), ENG 3044 (Signal Above Range Max), or ENG 3045 (Signal Below Range Min).

1. 1

   Park machine

   Park the machine on a level surface, engage the parking brake, and turn off the engine.

2. 2

   Locate sensor

   Locate the vehicle speed sensor. On most New Holland tractors, it is a magnetic pick-up or Hall-effect sensor located at the rear of the vehicle transmission or on the transmission axle housing.

3. 3

   Disconnect harness

   Disconnect the electrical harness connector from the sensor.

4. 4

   Remove retaining bolt

   Remove the retaining bolt holding the speed sensor to the transmission housing.

5. 5

   Remove old sensor

   Carefully pull the old speed sensor out of the housing. (Note: Have a catch pan ready, as a small amount of transmission/hydraulic fluid may seep out).

6. 6

   Lubricate O-ring

   Lubricate the O-ring on the new vehicle speed sensor with clean transmission fluid to prevent tearing during installation.

7. 7

   Install new sensor

   Insert the new sensor into the housing and tighten the retaining bolt to the OEM torque specification.

8. 8

   Reconnect harness

   Reconnect the electrical harness connector, ensuring it clicks securely into place.

9. 9

   Clear fault codes

   Use a diagnostic scan tool (such as the CNH EST) to clear the inactive fault codes.

10. 10

    Test drive

    Test drive the machine to verify that the ECM is reading a plausible speed signal and the ENG 3046 code does not return.