Injector electrical control depends on the ECU driver circuit.

In some intermittent faults, the injector itself may be functional while the driver circuit becomes unstable as temperature rises.

Driver Circuits Operate Under Electrical Load

The ECU must repeatedly energize injector actuators.

Heat can develop inside electronic components, especially when the circuit operates for long periods.

If a driver circuit becomes marginal, symptoms may appear only:

• after warm-up;
• under repeated injection demand;
• during extended operation.

Why the Fault May Disappear After Cooling

An electronically temperature-sensitive fault may recover after the ECU cools.

This can make workshop diagnosis difficult if the engine is tested only after a long shutdown.

Compare Command Signals

Useful observations can include:

• injector command;
• current waveform;
• cylinder fault timing;
• ECU temperature environment.

If the fault consistently affects the same driver channel while injector hardware tests normally, the ECU control path deserves attention.

Avoid Repeated Injector Replacement

If several replacement injectors produce the same cylinder-specific electrical problem, the driver circuit should be investigated.

Conclusion

Intermittent injector electrical faults can originate on either side of the connector.

The injector, wiring and ECU driver should all remain within the diagnostic boundary.