Hybspec

U1115

Wysoki

Missing or incorrect charging system data – loss of communication with the alternator module via the CAN network. The controller does not receive correct data regarding the battery voltage and charging status.

OBD-II (EN): Charging System Data Invalid - Loss of Communication with Alternator Module via CAN

Code U1115 signals missing or incorrect charging system data transmitted via the CAN network – most often it means a communication problem between the alternator and the vehicle's controller. The cause could be damaged wires, corroded connectors, or a malfunction of a modern digitally controlled alternator. Due to the complexity of CAN network diagnostics, a visit to a workshop with a professional diagnostic scanner is recommended.

Symptoms

Battery warning light illuminated on the dashboard; difficulty starting the engine or complete failure to start; visible voltage drops during operation (dimming lights, tachometer fluctuations); communication errors stored in multiple controllers simultaneously; possible shutdown of electrical consumers.

Possible causes

• Damaged or chafed CAN bus wiring harness near the alternator or energy management module • Oxidized or corroded electrical connectors of the alternator, ECU, or BCM • Malfunction of the alternator with a digitally controlled voltage regulator (smart alternator) • Damage or incorrect configuration of the ECU/BCM controller responsible for receiving charging data • Open circuit or short circuit on the CAN-Bus line (High or Low) between the charging system nodes

Affected systems

Sieć CAN-BusSystem ładowania / alternatorECU (sterownik silnika)BCM (moduł sterowania nadwoziem)System zarządzania energiąAkumulator / instalacja elektryczna

Related codes

U1120Wysoki

Błąd komunikacji modułu sterującego ABS z innymi modułami pojazdu. Kod wskazuje na utratę lub zakłócenie sygnału w sieci CAN bus między sterownikiem ABS a pozostałymi jednostkami sterującymi.

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Does code U1115 require professional diagnostics?

The code alone is not enough. To find the cause, you need to read live data, check freeze frame conditions, and compare with vehicle behavior. Book a diagnostic session.