Case IH 3674 – Engine Controller / ECU / EDC: EGR Valve Circuit - Under Voltage Error For H-Bridge

The H-bridge circuit responsible for controlling the Exhaust Gas Recirculation (EGR) valve is experiencing an under-voltage condition. This error is triggered by high voltage fluctuations within the vehicle's electrical system.

• Farmall
• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• backhoe loaders
• tractor models

1. 1

   Test the vehicle's electrical system for high voltage fluctuations

2. 2

   Check the condition and charge of the batteries

3. 3

   Inspect the alternator for proper voltage output and stability

4. 4

   Examine wiring harnesses and ground connections for damage, corrosion, or loose fittings

1. 1

   Inspect the Electrical System

   Check the vehicle's electrical system (batteries, alternator, wiring harnesses, and grounds) to identify and repair the source of the high voltage fluctuations.

2. 2

   Replace the ECU

   If the electrical system is verified to be stable but the fault persists, the Engine Controller (ECU) has likely been damaged by the voltage fluctuations and must be replaced.

3. 3

   Restore Parameters

   After replacing the Engine Controller (EDC), you must use the appropriate Case IH electronic service tool to restore the engine's self-learning parameters.