What it means
Fault on the ignition START input — module does not see start request when cranking, or sees one when not cranking.
At a glance
- Usually lights the warning light of the system that lost communication
How it works
The control module monitors the ignition START input to recognize a request to crank the engine. U3010 sets when the start signal is absent during cranking or appears when no start request is being made.
Common causes
Most likely first.
- Start position contacts worn
- Gateway module routing CAN messages incorrectly
- 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
- Scan all modules and save freeze-frame or event data, noting whether the code occurred during an attempted start or with the ignition at rest.
- Watch the module’s START input live data while operating the key or start control to see whether it follows the request.
- Inspect the START switch contacts, input connector, and wiring for wear, loose terminals, corrosion, or damage.
- Test the START input circuit during a start request and when no request is made, comparing results with the manufacturer’s wiring information and specification.
- If the circuit signals are correct at the module, check for related communication faults and investigate gateway routing or CAN operation.
Common fixes
- Repair a loose or damaged START input wire, terminal, or connector.
- Replace the ignition switch or start control if its START contact fails the specified checks.
- Repair the gateway or CAN network fault if it is preventing correct start-state communication.
Can I keep driving?
Avoid driving until the vehicle starts reliably and the start signal is not appearing unexpectedly. A faulty START input can prevent starting or cause unintended starter operation, which can damage components.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.