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B170F12

DTC B170F12 indicates a short to power in the right side curtain airbag ignition circuit — Atto 3

Safety System

DTC B170F12 indicates a short to power in the right side curtain airbag ignition circuit.

In the BYD SRS (Supplemental Restraint System) architecture, this fault indicates the airbag control unit (ACU) detects an abnormally low-impedance connection between the right side curtain airbag igniter circuit (typically two wires: high-side driver and low-side driver) and the vehicle power supply (+12V or +B).

This hardware short-to-battery fault may cause: 1) risk of unintended airbag deployment (in extreme cases); 2) airbag failure to deploy during a collision; 3) the SRS entering protection mode, disabling related airbag functions.

The '12' suffix in the BYD diagnostic protocol typically designates the specific 'short to power' subtype.

5
Cases Logged
Real-World Cases
BYD DTC AI Analysis

Chafed B-pillar wiring harness caused short to power.

✓
A 2019 BYD Qin Pro DM with 30,000 km had the SRS warning light on. Retrieved DTC B170F12. Removed the right-side B-pillar trim and found the curtain airbag harness insulation worn through at the clip location, with exposed copper wires contacting a constant power wire on the body. The cause was a missing harness clip that allowed the harness to rub and wear through. Repaired the damaged wiring, rerouted and secured the harness, and resolved the fault.
BYD DTC AI Analysis

Sunroof leak caused a short circuit in the curtain airbag connector.

✓
The owner of a 2020 E3 reported the airbag warning light illuminated on the dashboard after rain. Inspection found visible water stains inside the right-side C-pillar curtain airbag connector; oxidised pins caused a short circuit. Further checks found the sunroof drain hose detached, letting rainwater into the C-pillar. Cleaned the water stains, replaced the curtain airbag connector (repaired the pins), reinstalled the drain hose, and cleared the fault.
BYD DTC AI Analysis

Aftermarket dash cam installation pierced wiring harness

✓
2019 E2 logged B170F12 the day after an aftermarket shop installed a dashcam. Inspection found a self-tapping screw used during the wiring work had pierced the right-hand roof curtain airbag harness, causing a short between the power wire and airbag igniter line. Repaired the damaged harness (soldered and insulated with heat-shrink tubing), rerouted the dashcam wiring clear of the airbag loom, and resolved the fault.
BYD DTC AI Analysis

Internal short circuit in curtain airbag igniter

✓
A 2018 Qin Pro petrol was in a right-side collision. A repair shop fitted an aftermarket right curtain airbag, after which the vehicle logged DTC B170F12. The replacement airbag showed normal resistance, but the fault remained after installation. Disassembly and inspection revealed the aftermarket airbag's internal igniter had defective insulation, causing a short to the housing (the housing had an unintended electrical path to body power via the mounting bracket). Installing a genuine right curtain airbag assembly fixed the fault.
BYD DTC AI Analysis

SRS control unit driver chip fault

✓
A 2019 Qin EV with no accident history developed intermittent SRS warning light illumination during normal use, with DTC B170F12 appearing sporadically. Inspection of the wiring harness and connectors found no faults, and wiggling the harness did not reproduce the fault. Measuring the ACU output terminals revealed abnormal voltage leakage at the right side curtain airbag drive terminal. The cause was poor thermal stability of the high-side driver chip inside the SRS control unit. Replacing the SRS control unit and performing online programming (VDS2000 or a dedicated diagnostic tool) completely resolved the fault.
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.