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P1197

Key Off Voltage Low.

  • Ford
  • Powertrain
  • Manufacturer code
  • Low severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
1
AreaFuel and air metering
97
FaultThe specific fault in that area

What it means

On Ford (and related Lincoln and Mercury) vehicles, P1197 means 'Key Off Voltage Low'. The powertrain control module (PCM) saw the voltage on its keep-alive or key-off power supply fall below the expected level after the ignition was switched off. This points to a problem with battery voltage supply, the PCM power or ground circuits, or something draining the battery with the car parked. Exact circuits and test limits vary by model and engine, so check the relevant wiring diagram.

Symptoms

  • Check engine light on
  • Hard starting or slow cranking after the car has stood
  • Flat or weak battery after parking overnight
  • Lost radio presets, clock or learned idle and fuel trim settings
  • Rough idle or poor drivability after a battery disconnect or drain
  • Intermittent no-start

Possible causes

  • Weak, ageing or discharged batterylikely
  • Loose, corroded or dirty battery terminals and earth connectionslikely
  • Parasitic drain from an aftermarket accessory or a module that fails to sleeppossible
  • Faulty charging system leaving the battery underchargedpossible
  • High resistance or open circuit in the PCM keep-alive power feed, fuse or relaypossible
  • Faulty PCM internal power circuitrare

How to diagnose

  1. Read all stored and pending codes and freeze frame data, then note whether other voltage or charging codes are present
  2. Inspect battery terminals, earth straps and PCM connectors for corrosion, looseness or damage
  3. Test battery state of charge and condition with a load test, and check the resting voltage
  4. Test the charging system output with the engine running and under electrical load
  5. Check the fuses and relays that feed the PCM keep-alive and main power, using the model's wiring diagram
  6. Measure the parasitic current draw with the car locked and asleep, then pull fuses one at a time to find the circuit responsible
  7. Voltage-drop test the PCM power and ground circuits for high resistance
  8. Check for any fitted aftermarket alarms, trackers or audio equipment and their wiring

How to fix

  • Charge or replace the battery if it fails testing
  • Clean and tighten battery terminals and earth connections, and repair any damaged earth straps
  • Repair or remove faulty aftermarket accessories that cause a drain
  • Repair the alternator or charging system fault
  • Repair wiring, connectors, fuses or relays in the PCM power feed that show high resistance or open circuit
  • Replace or repair the PCM only after power, ground and battery faults have been ruled out

Can I keep driving?

Low severity

The car can normally be driven while you arrange a check, but it may fail to start if the battery is weak. Get the battery and charging system tested soon to avoid being stranded.

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

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