Faulty electrical load detector unit, usually in the under-bonnet fuse and relay box area; Open circuit, short to earth or chafed wiring in the ELD signal wire between the ELD and the ECU; Corroded, loose or damaged connector at the ELD or the ECU; Poor earth or low supply voltage to the ELD circuit; Charging system fault such as a weak battery or failing alternator affecting the signal; Faulty ECU.

P1297

ELD Circuit Low Input.

Acura
Powertrain
Manufacturer code
Low severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
2: AreaFuel and air metering (injector circuit)
97: FaultThe specific fault in that area

What it means

On Acura, P1297 means the engine control unit has seen a low voltage input on the Electrical Load Detector (ELD) circuit. The ELD measures the electrical load on the charging system so the ECU can adjust alternator output and idle speed. The code sets when the signal voltage stays below the expected range, which points to a fault in the ELD, its wiring or the supply and earth feeding it.

Symptoms

Malfunction indicator lamp on
Idle speed unstable, hunting or dipping when electrical loads such as headlights or the rear screen heater are switched on
Battery warning light or a flat or poorly charged battery in some cases
Possible stalling or rough idle at low speed with heavy electrical load
Other charging or electrical load codes stored alongside

Possible causes

Faulty electrical load detector unit, usually in the under-bonnet fuse and relay box arealikely
Open circuit, short to earth or chafed wiring in the ELD signal wire between the ELD and the ECUlikely
Corroded, loose or damaged connector at the ELD or the ECUlikely
Poor earth or low supply voltage to the ELD circuitpossible
Charging system fault such as a weak battery or failing alternator affecting the signalpossible
Faulty ECUrare

How to diagnose

Read all stored codes and freeze frame data, noting engine speed, load and battery voltage when the code set, then check for other charging or electrical codes
Visually inspect the ELD, its connector and the wiring harness for corrosion, water ingress, heat damage or chafing
Test battery condition and charging voltage at idle and with loads switched on, as a charging fault can distort the ELD signal
Check the supply voltage and earth at the ELD connector against the manufacturer's data for your model
Watch the ELD signal voltage on live data while switching electrical loads on and off, and see whether it responds
Test the ELD signal wire for continuity and for a short to earth between the ELD and the ECU with the connectors disconnected
Check the ELD component against the manufacturer's specification, as the location and test values vary by model and year
Clear the code after repair and road test to confirm it does not return

How to fix

Replace the electrical load detector if it fails testing
Repair or replace damaged or shorted ELD wiring
Clean, repair or replace corroded or loose connectors and terminals
Restore a good earth or supply feed to the ELD circuit
Replace a weak battery or repair the charging system if it is found to be at fault
Diagnose and replace the ECU only after all other causes are ruled out and confirmed by the manufacturer's procedure

Can I keep driving?

Low severity

The car can normally be driven and booked in for diagnosis soon. Keep an eye on the battery and charging condition, and have it checked promptly if the idle becomes unstable, the engine stalls or the battery warning light appears.

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