P1197 Key Off Voltage Low (Diesel)

Category: Powertrain - Computer and Auxiliary Controls
Severity: Check Engine Light
Applies to: Ford diesel models with electronic injection control

What does P1197 mean on a Ford?

P1197 — Key Off Voltage Low (Diesel). This Ford-enhanced code applies to Ford diesel models with electronic injection control.

Common causes of P1197

Discharged batteries
Parasitic drain overnight
Corroded cable ends
Failing battery with a dead cell
Controller sense wiring fault

How to fix P1197

Charge and load-test the batteries
Test for parasitic drain
Clean cable connections
Verify voltage at the controller
Replace failing batteries