Case IH tB4 – PCU (Powertrain Control Unit) / Transmission Controller: CAN VE Message (Speed Set point), Data Valid But Below Normal Range.

This code indicates a faulty setpoint speed signal being sent from the central controller (XCM) to the engine control module. The engine remains enabled, but the maximum engine speed is restricted to a limp-mode threshold of 1,760 RPM. Possible failure modes include a faulty connector, faulty wiring harness, or a failure within the XCM or Engine Control Module itself.

• MXM
• Case IH MXM 120
• Case IH MXM 130
• Case IH MXM 140
• Case IH MXM 155
• Case IH MXM 175
• Case IH MXM 190
• Case IH MXU Series
• Puma
• Maxxum
• Magnum

1. 1

   Turn the Power OFF and Keyswitch OFF, then disconnect the connectors at each end of the CAN circuit to prevent false readings.

2. 2

   Check harness continuity and resistance by setting a multimeter to ohms. Touch the red meter lead to the connector pins (one at a time) and the black lead to a plated metal chassis ground.

3. 3

   Evaluate the resistance: the circuit is continuous if the resistance is no more than 3 to 4 ohms. Higher resistance indicates dirty or corroded terminals, while a reading of 100K ohms indicates an open circuit.

4. 4

   Check the clutch pedal potentiometer by disconnecting connector C077. While operating the clutch pedal, measure the resistance on the component side between C077 pin 2 (Y/R/B) and C077 pin 3 (B). The reading should indicate between 0.90K Ohms and 3.7K Ohms.

1. 1

   Wiring Repair

   If the resistance tests fail, locate the faulty wire or connector. Remove the connector and harness outer covering. Use a harness repair kit to remove the incorrect pins, splice in the required length of new wire following the original harness routing, and re-pin the connector.

2. 2

   Component Replacement

   If the wiring and connectors are intact but the fault persists, replace the transmission speed sensor or the clutch potentiometer (depending on which component failed the resistance/voltage checks).

3. 3

   Transmission Calibration

   Apply the parking brake, turn off A/C and all hydraulic services. Hold the High and Low range buttons and start the engine. Release the buttons when "CAL" appears on the transmission display. Set the engine speed to 1200 ERPM. Follow the on-screen prompts until "END" displays, signifying the calibration is complete.