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U1005-00

DTC U1005-00 indicates a short circuit between the Supplemental Restraint System (SRS) Controller Area Network (CAN) communication line and vehicle power (+B) — Atto 3

Safety System

DTC U1005-00 indicates a short circuit between the Supplemental Restraint System (SRS) Controller Area Network (CAN) communication line and vehicle power (+B).

In BYD Qin series models, the Airbag Control Module (ACM) communicates with the vehicle network via the CAN bus.

When the CAN-H or CAN-L line shorts to constant power or ignition power, the short pulls the bus voltage up to 12V (battery voltage), distorting the CAN signal and interrupting communication.

This prevents the airbag system from receiving crash sensor signals or triggering airbag deployment, and may affect safety-related functions such as the seat belt pretensioners and the airbag warning lamp.

Because the CAN bus uses differential signal transmission, a short to power disrupts communication across the entire CAN network segment (typically including the instrument cluster and BCM).

This serious fault endangers driving safety.

5
Cases Logged
Real-World Cases
BYD DTC AI Analysis

Qin EV300: Worn floor harness caused CAN short to power

✓
A 2017 Qin EV300 with 80,000 km displayed "Check SRS System" on the instrument cluster and the airbag warning light remained on. The scanner read DTC U1005-00. Inspection found the floor harness retaining clip beneath the driver's seat rail had detached. The harness had chafed against the seat rail, wearing through the CAN-H line insulation and shorting it to the seat heater power line (+B). Repair: Cut out the 20 cm damaged section, re-soldered and double-insulated the joint, replaced the retaining clip, and rerouted the harness clear of moving parts. This cleared the fault and restored normal communication.
BYD DTC AI Analysis

Qin 80: Airbag control module connector corroded after driving through water

✓
2017 BYD Qin 80 set DTC U1005-00 after wading through heavy floodwater, with a damp musty odour inside. Inspection found water had reached sill height. The airbag control module (ACM) connector seal under the centre console had degraded, letting water into the connector and causing electrolytic corrosion that shorted the CAN bus pins to constant power. Resolution: Disconnected the battery, thoroughly cleaned the connector terminals with precision instrument cleaner and ultrasonic cleaning, dried them with compressed air, applied conductive anti-corrosion grease, and replaced the waterproof seal. ACM internals were undamaged, so the module didn't need replacement. Also inspected and cleared the drain holes to prevent future water ingress.
BYD DTC AI Analysis

BYD Qin EV450: Aftermarket Large-Screen Navigation Triggered CAN Bus Fault

✓
A 2018 BYD Qin EV450 threw a U1005-00 code and the factory multi-function steering wheel stopped working after an aftermarket workshop fitted a third-party Android head unit. Inspection found the installer had tapped into the dashboard wiring harness CAN bus using insulation-piercing connectors to get a vehicle speed signal, but clamped the CAN-H line to the head unit's constant power (+12V), shorting the CAN bus to power. Repair: Removed the unauthorized wiring, cut out the damaged CAN section (approximately 15cm), resoldered the connections per factory wire order with proper insulation, and restored the original harness layout. Replaced the damaged CAN bus termination resistor (located in the dashboard harness). Restored the factory navigation system; fault cleared.
BYD DTC AI Analysis

Internal circuit breakdown in Qin 100 ACM caused short circuit

✓
A 2017 Qin 100 suddenly showed the airbag warning light during normal operation. Scanned U1005-00. Checked the harness—no damage or water ingress. Measured 12V on the CAN lines at the ACM connector. Disconnected the ACM and measured normal voltage (2.5V/2.3V) on the harness side. Confirmed the ACM’s internal transceiver circuit failed, shorting the CAN pins to internal power. The Qin 100’s ACM and airbag trigger IC are too highly integrated to allow separate circuit board repair. Replaced the OEM airbag control module (PN: BYD-3638100-X), coded and configured it using VDS2000, performed the airbag system calibration, and cleared the fault codes. System returned to normal.
BYD DTC AI Analysis

BYD Qin EV300: Wiring harness improperly secured after accident repair

✓
A Qin EV300 with front-end collision damage threw an intermittent U1005-00 code after dealership repairs. The crash repair replaced the instrument panel harness, but the firewall grommet was not installed correctly, letting the CAN harness contact the heater pipe bracket. Motor vibration rubbed the harness against the bracket, causing intermittent shorts to power (the bracket grounds to the body, but a nearby +12V wire had insulation damage). Fix: Reroute the instrument panel harness, secure with OEM clips, add a rubber grommet at the firewall, repair the damaged power wire insulation, and keep the harness 20mm clear of metal components. The fault has not returned.
Other Atto 3 Fault Codes
P0A0DBattery Energy Control Module Requested MIL IlluminationP0AA6Hybrid Battery Voltage System Isolation FaultP1A00Drive Motor "A" Performance — BYD proprietaryB1108For the BYD Song MAX (2017–2019), DTC B1108 indicates a short circuit in the PM2.5 air quality detection module (dust sensor) or its wiring harness. The sensor uses laser scattering to detect in-cabin and outside PM2.5 concentrations and transmits data to the HVAC ECU via the LIN bus or an analog signal. Short circuit conditions include: 1) Sensor power supply wire (+5V/+12V) shorted to ground 2) Signal wire shorted to power or ground 3) Short circuit in the sensor's internal photoelectric detection circuit This fault prevents the automatic climate control from switching between fresh air and recirculation based on air quality. The system enters fail-safe mode (typically forced recirculation). Severe short-circuit current can destroy the HVAC ECU sampling circuit. The system classifies this as a Level 3 severe fault and restricts vehicle operation to prevent electrical fires or controller damage. For other BYD models (such as the Qin EV, E5, and Song DM), B1108 indicates a driver-side sunload sensor fault, reflecting differences in DTC definitions across models.B110811This DTC indicates a short circuit in the air conditioning system PM2.5 air quality sensor (rapid detector). Specifically, abnormal continuity exists between the sensor power supply circuit or signal output circuit and body ground or battery positive. This causes the control module (ACU/air conditioning controller) to detect abnormal current or a voltage signal outside the valid range (typically 0V or supply voltage). The PM2.5 sensor monitors internal and external particulate concentrations, providing the data the automatic air conditioning system uses to switch between fresh air and recirculation modes. A short circuit disables the air quality monitoring function. This fault may force the air conditioning system into recirculation protection mode and trigger related thermal management system faults, as the air conditioning system acts as a key actuator in vehicle thermal management. In severe cases, the short circuit current can damage the internal sampling circuit of the air conditioning controller or overheat the wiring harness.
Data confidence: Community This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.