Open circuit, chafed wiring or short in the lamp control wiring; Corroded, loose or damaged connector at the instrument cluster or control module; Faulty stop-start lamp or instrument cluster circuit (failed LED or driver); Faulty stop-start switch or related input wiring causing a wrong lamp state; Low battery voltage or poor earth connections upsetting the lamp driver monitoring; Internal fault in the controlling module's lamp driver.

P06F4

Stop-Start Mode Lamp Control Circuit.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
6: AreaComputer and output circuits
F4: FaultThe specific fault in that area

What it means

P06F4 means the control module that drives the stop-start mode lamp has found a fault in the lamp's control circuit. It compares the commanded state of the lamp driver with the voltage it actually sees on the circuit, and sets the code when they do not match, for example an open circuit, a short to ground or a short to voltage. Which module owns the circuit (engine, body or a dedicated stop-start module) depends on the vehicle.

Symptoms

Stop-start indicator lamp stays on, stays off or flickers
Stop-start lamp does not light when the system is active or switched off
Stop-start function may be unavailable or inconsistent
Engine management or general warning lamp may be on
Other instrument cluster lamps may behave oddly if the cluster is at fault

Possible causes

Open circuit, chafed wiring or short in the lamp control wiringlikely
Corroded, loose or damaged connector at the instrument cluster or control modulelikely
Faulty stop-start lamp or instrument cluster circuit (failed LED or driver)possible
Faulty stop-start switch or related input wiring causing a wrong lamp statepossible
Low battery voltage or poor earth connections upsetting the lamp driver monitoringpossible
Internal fault in the controlling module's lamp driverrare

How to diagnose

Read all stored and pending codes and freeze frame data, and note any battery, charging or communication codes alongside P06F4
Check the battery condition and charging voltage, as low voltage can upset stop-start systems and cause false circuit faults
Check the stop-start lamp in the cluster during the bulb or lamp check at ignition on, and operate the stop-start switch to see whether the lamp responds
Inspect the wiring and connectors between the cluster and the controlling module for chafing, water ingress, corrosion and pushed-out pins
Using the wiring diagram for the model, test the lamp control circuit for continuity, short to ground and short to supply
Check the relevant earth points and supply fuses for the lamp circuit
Use a scan tool to command the lamp on and off, if the vehicle supports it, and compare the response with the live circuit voltage
Clear the code after repair and road test to confirm it does not return

How to fix

Repair or replace damaged wiring and restore any open or shorted circuit
Clean, repair or replace corroded or damaged connectors and terminals
Repair or replace the instrument cluster or faulty lamp element if it is found to be the cause
Replace a faulty stop-start switch or correct its wiring
Restore battery health and clean or tighten earth connections
Replace or repair the controlling module only after the wiring and supply have been proven good

Can I keep driving?

Low severity

The car can normally be driven, as this is a lamp circuit fault, but the stop-start function may not work. Book it in for diagnosis, and sooner if there are battery or charging warnings too.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.