What it means
Fault on the ON/START ignition output. A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.
At a glance
- Usually lights the warning light of the system that lost communication
How it works
The ON/START output supplies or signals ignition power for circuits that must operate with the ignition on and during engine starting. The module monitors the line against the requested state; this code indicates the ON/START output is faulty and may disrupt starting or powered systems.
Common causes
Most likely first.
- Wiring or relay fault
- 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
- Record all module codes and freeze-frame details, noting whether the problem occurs with ignition on, during cranking, or both.
- Use a scan tool to compare the commanded ON/START state with the reported output and check which modules lose power or communication.
- Inspect the ON/START wire, connectors, fuse connections, and related relay for damage, corrosion, looseness, or heat marks.
- Test the output and relay response in ON and START states following the manufacturer's circuit procedure.
- If the output circuit passes, investigate gateway routing and CAN termination when accompanying communication faults are present.
Common fixes
- Repair a damaged ON/START output wire or connector.
- Replace a relay or repair a fuse connection after confirming the fault.
- Correct a confirmed gateway routing or configuration fault.
- Repair CAN termination if testing shows it is outside specification.
Can I keep driving?
Do not rely on the vehicle for a trip if it stalls, fails to start consistently, or loses essential electrical functions. A brief necessary drive is only reasonable if it runs and all safety-related systems work normally.
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.