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P1197

Key Off Voltage Low.

  • Other
  • 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

P1197 is listed here as 'Key Off Voltage Low', the definition used by Ford-group vehicles. The make was not specified, so confirm that this definition applies to your vehicle before diagnosing. The control unit saw a voltage below its expected limit on a monitored circuit or supply when the ignition was switched off, so it stored the fault.

Symptoms

  • Engine management warning light on
  • Hard or slow starting, especially after the car has stood
  • Stored settings, learned values or readiness status lost or reset
  • Flat or weak battery after the car has been parked
  • Intermittent electrical oddities such as clock or radio memory loss

Possible causes

  • Weak, discharged or ageing battery giving low voltage at key offlikely
  • Loose, corroded or poor battery terminals or earth connectionslikely
  • Poor power or ground supply to the engine control unit, such as a bad fuse, relay or connector pinpossible
  • Parasitic drain from an aftermarket accessory or faulty module keeping the system awakepossible
  • Charging system fault leaving the battery underchargedpossible
  • Wiring damage or high resistance in the monitored circuit (model dependent)rare
  • Internal fault in the engine control unitrare

How to diagnose

  1. Confirm the code definition for the specific make and model, and read freeze frame data and any other stored codes.
  2. Check battery voltage at rest. A healthy battery should read about 12.4 to 12.7 volts.
  3. Inspect the battery terminals, clamps, main fuses and earth straps for looseness, corrosion or damage.
  4. Load test the battery and check the charging voltage with the engine running.
  5. Check the engine control unit fuses, relays, power and earth connections, and inspect the connector for corrosion or bent pins.
  6. Carry out a parasitic drain test with the car asleep and look for accessories or modules that stay awake.
  7. Check wiring for chafing or high resistance using the manufacturer's wiring diagram for the affected circuit.
  8. Clear the code, then test drive and recheck to see whether it returns.

How to fix

  • Charge or replace the battery if it fails the load test.
  • Clean and tighten the battery terminals and earth connections, and replace any damaged leads.
  • Repair or replace faulty fuses, relays, connectors or wiring in the control unit supply and earth circuits.
  • Fix or remove the cause of any parasitic drain, such as a faulty accessory or module.
  • Repair the charging system, for example the alternator or its wiring, if charging is low.
  • Replace or reprogram the engine control unit only after the supply, earths and wiring have all tested good.

Can I keep driving?

Low severity

The car can normally be driven, but book it in soon because a weak battery or poor supply can leave you with a no-start. If starting becomes difficult or other warning lights appear, get it checked sooner.

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

This code for other makes

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