Case IH 2815 – TCU: Governor Engine RPM Alternator Mismatch

This fault code is triggered when the engine RPM speed signal sourced from the alternator is excessively high, or when the engine speed reported by the Engine Controller or Instrumentation Controller does not match the speed signal being generated by the alternator.

• Magnum
• Magnum 235 - 340 (Series 4)
• Steiger
• Quadtrac
• Maxxum (110 EP - 140 EP)
• Puma

1. 1

   Check for related codes that might isolate the issue, such as ENG 115 (Engine Speed Sensor failure) or Trans 2817 (Governor is offline CAN bus).

2. 2

   Inspect the alternator speed signal terminal and wiring for shorts, corrosion, or loose connections.

3. 3

   Inspect the engine speed sensor (crank/cam sensor) and its harness for damage.

4. 4

   Check alternator output and ensure the alternator drive belt is not slipping, which can cause erratic speed signal generation.

1. 1

   Disconnect power

   Turn off the machine and disconnect the battery to protect the CAN-bus network and controllers.

2. 2

   Repair wiring harness

   Trace the speed signal wire from the alternator to the transmission/instrumentation controller. Repair any chafed wires or shorts to ground/power that could cause an excessively high false reading.

3. 3

   Replace engine speed sensor

   If the engine controller is providing the faulty baseline RPM (often accompanied by code ENG 115), locate the engine speed sensor on the engine block. Remove the mounting bolt, pull the old sensor, install the new OEM sensor, and reconnect the harness.

4. 4

   Replace alternator

   If the wiring is intact and the engine speed sensor is functioning, but the alternator's internal speed signal output is failing or erratic, remove the drive belt, disconnect the alternator harness, and replace the alternator unit.

5. 5

   Clear codes

   Reconnect the battery, power on the machine, and clear the pending/active fault codes from the Transmission controller to verify the fix.