Code
P1298
HONDA
P — Powertrain
Electrical Load Detector Circuit High Voltage
Views:
UK: 16
EN: 48
RU: 47
AI status
Completed
Completed
100%
Causes
- Open or shorted ELD wiring (short to battery voltage/B+ or open/high impedance)
- Faulty alternator/ELD sensor/integrated regulator
- Corroded/loose connector at alternator or ECM
- Poor battery or chassis ground(s)
- Blown or shorted fuse or fusible link in charging circuit
- Intermittent connector contact or water ingress
Symptoms
- Battery/charging system warning lamp on dash
- Incorrect charging behavior (overcharging or no charge)
- Battery drainage or poor charge retention
- Possible hard starting or stalling after electrical load changes
- Other electrical anomalies (fuses blowing, accessories malfunction)
What to check
- Scan vehicle and record freeze frame data and related stored codes (P0562/P0563/P0625/etc.)
- Visually inspect alternator connector, wiring harness, battery terminals, and ground straps for damage, corrosion, or loose connections
- Check battery static voltage (key OFF) and system voltage with key ON and engine running
- Backprobe ELD terminal at alternator connector and at ECM while monitoring voltage (key ON/engine OFF and engine running)
- Check continuity and resistance of ELD wire between alternator and ECM; check for shorts to B+ and to ground
- Inspect/verify fuses and fusible links in charging/ELD circuits
Signal parameters
- Typical system battery voltage (key OFF): ~12.0–12.8 V
- Typical system voltage (engine running): ~13.5–14.8 V
- ELD signal nominal range: low-voltage values during low load, rising with load (manufacturer-specific). ELD circuits are expected to remain below the reference ‘high’ threshold (approx. under ~4.5–5.0 V on many designs)
- High condition: ELD signal measured at or above the manufacturer high-voltage threshold (varies by model)
- Expected wire continuity: low resistance between alternator ELD pin and ECM ELD pin (near 0 Ω–a few ohms)
Diagnostic algorithm
- Retrieve and record all DTCs, freeze frame and live data. Note battery voltage and ELD signal while code set.
- Visually inspect alternator connector, wiring harness, battery positive/negative terminals and engine/chassis grounds. Repair obvious damage.
- With key ON (engine OFF) backprobe ELD pin at alternator connector and at ECM; measure voltage. Compare both points — they should track and be within manufacturer limits.
- Check for short to B+: disconnect the alternator connector. If ELD voltage remains high with connector disconnected, suspect wiring short to battery/ignition or ECM fault.
- Check continuity and resistance of the ELD wire between alternator and ECM and to ground; check for short to battery (measure resistance to B+ with power removed).
- Inspect and test alternator/regulator per Honda service procedures (output, diode check, internal ELD sensor if serviceable). Replace alternator only after confirming alternator is faulty.
- Repair any damaged wiring, pins, connectors, or grounds. Reconnect and clear codes, then road-test and monitor live ELD signal and charging system.
- If wiring and alternator test good and problem persists, consider ECM input circuit testing or replacement per factory diagnostics (avoid ECM replacement until wiring and components are verified).
Likely causes
- Short to battery/ignition voltage on ELD wire
- Damaged alternator harness or connector pins
- Faulty alternator voltage regulator/ELD sensor
- Corroded ground at battery or engine block
- Connector not fully seated or wiring rubbed through
Fault status
Status
Electrical Load Detector (ELD) circuit voltage higher than expected (Circuit High)
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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