What it means
Stop-Start Mode Lamp Control Circuit: the control circuit has an electrical fault.
At a glance
- Usually lights the check-engine light
How it works
The stop-start lamp circuit carries the control module's command to the instrument cluster or lamp that indicates stop-start status. P06F4 sets when the module detects an electrical fault in that lamp-control circuit; it does not by itself prove that the stop-start system has failed.
Common causes
Most likely first.
- Open or short in stop-start lamp wiring
- Faulty warning lamp or instrument cluster
- Poor connector contact
- Control module output fault
Symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
How to diagnose it
- Scan for related instrument-cluster and stop-start codes, and note whether the stop-start lamp behaves incorrectly when the system is enabled or disabled.
- Inspect the instrument-cluster and stop-start circuit connectors for loose pins, corrosion, or damaged wiring.
- Check the lamp or cluster display operation using the vehicle's normal self-check, if available, and confirm whether the indicator itself is functioning.
- Use the wiring diagram to test continuity and shorts in the lamp-control circuit between the control module and cluster against the manufacturer's specification.
- If wiring and lamp operation are sound, follow the vehicle's diagnostic procedure to check the module output and any required post-repair relearn.
Common fixes
- Repair an open or shorted stop-start lamp wire.
- Clean and secure poor connector contacts in the lamp-control circuit.
- Replace or repair the instrument-cluster lamp/display if it fails its check.
- Repair the control module output or complete the specified relearn if circuit tests identify that need.
Can I keep driving?
This code usually concerns the stop-start indicator circuit, so normal driving is generally possible if no other warnings or drivability symptoms appear. If multiple warnings or a no-start condition occur, stop safely and have the vehicle assessed.
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.