P1191: Key Line Voltage

What does P1191 mean?

P1191 is a diagnostic trouble code indicating "Key Line Voltage". This code relates to your vehicle's electrical/charging and should be diagnosed to determine the root cause. The severity level helps indicate how urgently this should be addressed.

Symptoms you may notice

• Check engine light (MIL) illuminated on dashboard
• Possible issues with electrical/charging operation
• Vehicle may enter reduced power mode (limp mode)

Common causes

• Faulty electrical/charging component
• Wiring or connector issue in the related circuit
• Failed sensor providing incorrect readings
• Software/calibration issue requiring ECU update
• Related component causing secondary fault

What should you do?

This code sits in the immobiliser or vehicle security system. Braking and steering are not affected, but the car may refuse to start or strand you somewhere inconvenient. Plan the repair rather than rushing it.