Case IH PB4 – Engine Control Module (ECM) or Vehicle Control Unit (VCU): CAN VE Message (Speed Set point), Data Valid But Below Normal Range

The control module is receiving a valid signal format over the Controller Area Network (CAN) bus regarding the vehicle's speed set point (often tied to the throttle position or cruise speed setting), but the data value falls below the minimum acceptable operational range.

• MXM
• Case IH MXM Series

1. 1

   Check the input data of the synchronization commands from external speed units (such as the foot pedal or hand throttle)

2. 2

   Inspect the CAN bus wiring harness for mass wire breaks, shorts to ground, or shorts to a high source

3. 3

   Check for abnormally low voltage on the signal wires or high resistance/oxidation at the terminal pins connecting the speed set point sensors to the control unit

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery to prevent electrical shorts while testing the CAN bus.

2. 2

   Inspect the Harness

   Trace the wiring from the speed set point sensor (throttle pedal/lever) to the ECM/VCU. Look for chafed wires or corroded pins.

3. 3

   Clean Terminals

   If oxidation or high resistance is found at the connectors, clean the terminal pins thoroughly and apply dielectric grease.

4. 4

   Test the Sensor

   Reconnect power and use a multimeter to verify the voltage sweep of the speed set point sensor. If the voltage drops below the normal threshold at the lowest setting, the sensor is internally faulty.

5. 5

   Replace and Calibrate

   Replace the faulty sensor or repair the damaged wiring harness. Clear the PB4 fault code using a diagnostic tool and perform a test run to ensure the speed set point data remains within the normal range.