New Holland ENG 3269 – Engine ECU: Grid Heater Switch On Test - Voltage Drop Too High

This fault code indicates an electrical resistance issue within the cold start system. When the Engine Control Module (ECM) commands the intake air grid heater relay to switch on, it performs a diagnostic test to measure the voltage drop across the circuit. A "Voltage Drop Too High" condition means there is excessive electrical resistance preventing the proper flow of current to the grid heater element. This is most commonly caused by a failing grid heater relay (solenoid) with burnt internal contacts, heavily corroded battery cable connections at the relay, or a damaged wiring harness.

• T8.275
• T8.300
• T8.330
• T8.360
• T8.390
• T8.420
• T7.165S
• T7.175
• T7.190
• T7.210
• T7.225
• T6.140
• T6.145
• T6.155
• T6.165
• T6.175
• B90B
• B100B
• B110B
• B115B

1. 1

   Ensure the machine's batteries are fully charged and load-tested, as low system voltage can trigger false voltage drop codes.

2. 2

   Visually inspect the grid heater relay and heavy-gauge power cables for melted insulation, loose retaining nuts, or heavy corrosion on the ring terminals.

3. 3

   Using a diagnostic scan tool, manually cycle the grid heater relay on and off and listen for a strong, audible click.

4. 4

   With a multimeter, measure the voltage drop across the relay's large terminals while the relay is commanded ON (a high voltage reading confirms internal failure).

5. 5

   Check the resistance of the grid heater element to ensure it is not shorted or completely open.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery cable(s) to prevent accidental arcing, as the grid heater circuit carries very high amperage.

2. 2

   Locate the Relay

   Locate the grid heater relay assembly (often mounted near the engine intake manifold or on a front frame bracket, depending on the model).

3. 3

   Remove Wiring

   Disconnect the small control harness connector from the relay. Remove the retaining nuts holding the heavy-gauge power supply cable and the grid heater feed cable.

4. 4

   Clean Terminals

   Thoroughly clean the ring terminals on the heavy-gauge cables with a wire brush or emery cloth. Corroded terminals will immediately cause a repeat "Voltage Drop Too High" code.

5. 5

   Remove and Replace

   Unbolt the faulty grid heater relay from its mounting bracket and install the new relay.

6. 6

   Reassemble

   Reattach the heavy-gauge cables to the new relay studs and tighten the nuts to the specified torque. Reconnect the control harness connector.

7. 7

   Test

   Reconnect the negative battery cable. Turn the ignition key to the ON position to initiate the cold start sequence. Verify the wait-to-start light illuminates and the relay engages. Clear the ENG 3269 fault code using your diagnostic tool.