New Holland ENG 3670 – ENGINE module: EGR Short to Battery on EGR Out2 pin A35 error for H-bridge

The Engine Control Unit (ECU) has detected a short circuit to battery voltage on the EGR valve's control circuit (Out2, corresponding to ECU pin A35). This means there is unwanted voltage on the return/control wire, which is typically caused by a wiring harness shorting to a power source or an internal short within the EGR valve motor itself.

• F5C
• F5H
• F5DF
• F5DG
• H5HF
• F5HG
• L218
• L220
• L221
• L223
• L228
• L230
• L321
• L328
• C227
• C232
• C237
• C238
• C327
• C332
• C337
• T4.55
• T4.65
• T4.75
• T4.80F
• T4.80V
• T4.90F
• T4.100F
• T4.100LP
• T4.100N
• T4.100V
• T4.105
• B100C
• B110C
• B115C

1. 1

   Visually inspect the wiring harness between the Engine ECU and the EGR valve for any signs of chafing, melting, or exposed wires that could cause a short to a 12V power source.

2. 2

   Disconnect the harness from the EGR valve and the ECU. Using a multimeter, test the wire corresponding to ECU pin A35 (EGR Out2) for continuity to battery power. If voltage is present while disconnected, the wiring harness is shorted.

3. 3

   Inspect the EGR valve connector and ECU connector for corrosion, water intrusion, or bent pins that could bridge the power and control circuits.

4. 4

   If the wiring harness tests good, the short is likely internal to the EGR valve's H-bridge motor circuit.

1. 1

   Isolate the Fault

   Perform the diagnostic checks above to determine if the fault is in the wiring harness or the EGR valve itself.

2. 2

   Repair Wiring

   If the wire at pin A35 is shorted to battery voltage, locate the chafe or melt point in the harness and repair the wire using OEM-approved splicing methods, or replace the engine wiring harness.

3. 3

   Replace the EGR Valve

   If the harness is intact, the EGR valve has failed internally. Drain the engine coolant, remove the intake/exhaust piping and electrical connector from the EGR valve, unbolt and remove the faulty EGR valve, clean the mounting surface, and install the new EGR valve with a new gasket.

4. 4

   Reassembly & Clearing

   Reconnect all components, refill the coolant, clear the ENG 3670 fault code using a diagnostic scan tool, and run the engine to verify the repair.