U0306: Software Incompatibility with Fuel Injector Control Module

What it means

The injector driver module identifies itself with a software version that does not match what the engine ECU expects. Engine may not start or runs roughly until both modules are reflashed to compatible versions.

At a glance

• Usually lights the warning light of the system that lost communication

How it works

The fuel injector control module drives or coordinates injector operation and exchanges its software identity with the engine ECU. U0306 sets when the reported injector module software does not match the version the ECU expects. An incomplete or incorrect flash can create this mismatch; a network routing fault can also prevent the expected identifiers from being received.

Common causes

Most likely first.

1. Software flash incomplete or wrong file
2. Gateway module routing CAN messages incorrectly
3. CAN terminating resistor (120 Ω) drifted out of spec

Symptoms

• Multiple warning lights may illuminate
• Affected modules may go into limp mode or shut down
• Specific functions inoperative depending on module
• Diagnostic tools may show communication faults

How to diagnose it

1. Scan the engine ECU, injector control module, and gateway for U0306 and related communication codes, and save freeze-frame data.
2. Note whether the engine starts, runs roughly, or has injector-related faults, and check live data for injector module communication status.
3. Review recent repairs and programming records for an interrupted flash, incorrect file, or replacement of the injector control module.
4. Compare the injector module and engine ECU software identifiers and configuration with the vehicle's required versions using a capable scan tool.
5. If the identifiers are correct but communication remains inconsistent, check gateway routing and network wiring using the manufacturer's procedure before condemning a module.

Common fixes

• Complete or repeat the injector control module flash with the correct vehicle-specific software.
• Correct the engine ECU or injector module configuration so their software versions are compatible.
• Repair a network wiring or gateway routing fault that prevents the modules exchanging identifiers.
• Replace a module only if it will not accept the correct programming or continues to fail communication checks afterward.

Can I keep driving?

If the engine will not start, runs roughly, or has reduced power, avoid driving because misfire or poor fueling can damage the catalyst and leave you without dependable acceleration. Arrange repair promptly, especially if the check-engine light flashes.