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B17041B

DTC B17041B indicates the SRS (Supplemental Restraint System) ECU detected an open circuit or abnormal resistance in the left curtain shield airbag circuit (typically >4 — Qin Plus

Safety System

DTC B17041B indicates the SRS (Supplemental Restraint System) ECU detected an open circuit or abnormal resistance in the left curtain shield airbag circuit (typically >4.8Ω or <1.0Ω).

This fault indicates an interrupted electrical connection between the left curtain airbag inflator and the SRS control unit.

Causes include a disconnected connector, a wiring harness open circuit, or an internal open circuit within the curtain airbag assembly.

This condition prevents the left curtain airbag from deploying during a side impact or rollover event, severely compromising occupant head protection.

Because the SRS uses a dual-stage deployment circuit, this DTC typically triggers a circuit resistance warning.

Read the live data stream with a dedicated diagnostic tool to confirm the exact resistance value.

The B17041B fault code on the Qin Plus indicates a medium-severity fault in the left curtain airbag circuit, usually due to an open circuit or abnormal resistance. Common causes include a loose or disconnected yellow airbag connector, or damaged wiring along the B/C-pillar or headliner area. The left curtain airbag may not deploy correctly, so visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Left-side curtain airbag connector loose or disconnected: Commonly occurs after headliner removal and installation, A/C-pillar trim repair, or seat removal and installation due to an incompletely locked yellow airbag connector (requires an audible secondary locking 'click').
  • 2Wiring harness open circuit or wear: The left curtain airbag wiring harness routes along the B-pillar, C-pillar, and headliner edge. Long-term vibration from door operation can break the internal copper core, or trim panel clips can crush the insulation layer, causing a hidden open circuit.
  • 3Internal open circuit in the left curtain airbag assembly: Burnt inflator igniter wire or broken internal bridge wire (often due to component aging or previous external impact). Static resistance measurement usually shows infinite resistance or deviates significantly from the standard value (2.0 ± 0.3 Ω).
  • 4Poor contact at the mating connector between the floor wiring harness and the body wiring harness: Water ingress or oxidation corrodes the terminals of the intermediate connector inside the left front door sill trim, creating a high-resistance connection.
  • 5SRS ECU internal fault or software calibration error: Control unit internal sampling circuit fault falsely reports an open circuit, or abnormal crash threshold calibration parameters require a software version upgrade.
What To Do
  • 1
    Safety Preparation: Set the vehicle to OFF, disconnect the 12V battery negative terminal, and wait at least 90 seconds (to fully discharge the SRS capacitor). Wear an anti-static wrist strap to prevent accidental airbag deployment.
  • 2
    Fault confirmation: Connect the VDS2000/Launch X431 diagnostic tool, read the fault code status (Current/History), check the live resistance value of the left curtain airbag (normal range 1.5-3.0Ω), and record the freeze frame data.
  • 3
    Visual inspection: Remove the left C-pillar trim panel and headliner edge. Check if the yellow airbag connector (usually marked 'CURTAIN L' or 'DAB L') is fully inserted. Confirm the secondary locking tab (CPA) is in the locked position. Inspect the wiring harness sheath for damage.
  • 4
    Resistance measurement: Disconnect the airbag connector. Use a digital multimeter to measure the curtain airbag side resistance (standard value: 2.0 ± 0.3 Ω). If the resistance is infinite or >5 Ω, replace the left curtain airbag assembly. Measure the harness side continuity (resistance from the SRS ECU terminal to the connector terminal should be <1 Ω). Check for a short to ground or short to power.
  • 5
    Substitution test: Connect a 2Ω dedicated airbag simulator to the circuit in place of the actual curtain airbag. Clear the fault code and turn the ignition switch ON. If the fault code disappears, the curtain airbag is faulty. If the fault code remains, check the wiring harness or ECU.
  • 6
    SRS ECU inspection: Measure continuity and insulation between the SRS ECU connector terminals (typically pins 21 and 22; refer to the vehicle wiring diagram) and the curtain airbag connector. Check the ECU power supply (constant power +B), ground (GND), and CAN communication lines.
  • 7
    Repair and verification: After repairing the wiring harness or replacing the faulty component, reconnect all connectors (listen for the locking click), connect the battery, clear the fault code, and perform an ignition cycle test (during the ON position self-check, the airbag warning light should illuminate for 6 seconds and then turn off). Perform an SRS system function test (use a diagnostic tool to trigger the circuit self-check; do not perform a tapping test).
Real-World Cases
BYD DTC AI Analysis

BYD E2 seat cover installation caused the left curtain airbag connector to detach.

✓
A 2019 BYD E2 came in with the airbag light on steady. Pulled code B17041B. The owner had recently had full-coverage seat covers fitted at a detailing shop. On tear‑down, we found the technician pulled the headliner harness when removing/installing the left front seat, loosening the yellow connector for the left curtain airbag—the secondary lock didn’t click. Reconnected the connector firmly and locked the CPA. Cleared codes, airbag light went out, resistance returned to 1.9 Ω. Recommendation: Disconnect the SRS system before removing or installing seats.
BYD DTC AI Analysis

Qin EV (flood damage): Left curtain airbag wiring harness corroded, open circuit

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2020 BYD Qin EV. The vehicle had previously flooded after wading through water deeper than the door sills. Following repairs, DTC B17041B set and would not clear. Removed the left front sill trim panel and found severe oxidation inside the intermediate connector joining the floor and headliner harnesses. The pins showed green copper corrosion. Checked continuity from this connector to the SRS ECU and measured over 10 ohms on one signal line (normal is under 0.5 ohms). Cut out the corroded section and re-crimped the terminals using waterproof heat-shrink tubing. Cleared the fault. Recommendation: When repairing flood-damaged vehicles, thoroughly inspect all airbag harness connectors and replace the complete harness assembly if necessary.
BYD DTC AI Analysis

E3: Internal open circuit in curtain airbag after accident repair

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BYD E3 sustained a side impact on the left. Replaced the left curtain airbag but DTC B17041B remained active. Measured the resistance of the new component with a multimeter; it showed infinite resistance, indicating a parts quality issue (improper storage or broken internal bridge wire). Replaced it with another genuine curtain airbag. The new part measured 2.1Ω. Installed it and cleared the fault. Curtain airbags are single-use components. Even if not deployed, severe vibration or dropping can damage the internal igniter. Always measure resistance before installation to confirm the component is serviceable.
BYD DTC AI Analysis

SRS ECU Software False Fault Report Upgrade Case

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Multiple 2019 Qin EVs intermittently set DTC B17041B during normal operation. Measured the curtain airbag resistance and wiring harness – both normal. Checked the BYD Technical Service Bulletin (TSB) and found that early-version SRS control software can falsely report open-circuit faults during voltage fluctuations (e.g., jump-starting after a flat battery). Upgraded the SRS ECU software using VDS2000 (from V1.02 to V1.05). The fault has not reoccurred since the upgrade. Recommendation: For intermittent faults with normal measurements, check the software version first.
BYD DTC AI Analysis

C-pillar trim clip pinched the wiring harness, causing an intermittent open circuit.

✓
The vehicle has no accident history, but the airbag warning light illuminated intermittently when driving over rough roads. The DTC retrieved was B17041B – intermittent fault. Removed the left C-pillar trim and found the wiring harness had been compressed by the trim clips over a long period, damaging the insulation and causing partial fracture of the internal copper strands. The circuit showed occasional continuity when tested statically but opened under vibration. Cut out the damaged section of the harness, re-routed it to avoid the sharp clip edges, and wrapped it with fleece tape. This permanently resolved the fault. Recommendation: When inspecting wiring, simulate vibration by lightly tugging the harness to test for continuity.
Other Qin Plus Fault Codes
B1108For 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.B110913DTC B110913 indicates an open signal circuit for the PM2.5 rapid detector (in-cabin air quality sensor). This sensor typically mounts inside the air conditioning system intake duct. It monitors in-cabin PM2.5 concentration in real time and provides data to the automatic air conditioning system for intelligent control of the air purification function. The BYD diagnostic protocol uses sub-code '13' to specifically indicate an open signal circuit. Although this fault theoretically affects a comfort feature, BYD Qin series vehicles classify it as a Level 3 (severe) fault. This classification occurs because the air conditioning system interacts with the battery thermal management system (e.g., monitoring battery cooling intake air quality). The fault can disable the automatic air conditioning mode and prevent the air purification function from operating. In extreme cases, it affects the battery compartment intake air quality assessment, triggering the 'repair immediately' strategy.B110BDTC B110B indicates a fault in the internal air pump (sampling pump) of the PM2.5 air quality detector. This pump draws cabin or outside air into the PM2.5 sensor detection chamber, enabling the laser scattering sensor to measure real-time particulate matter concentration. The air conditioning controller (or BCM) sets this DTC upon detecting an open or short circuit in the pump drive circuit, or abnormal current caused by a seized pump motor. This fault disables the "Green Clean" system, causes the instrument cluster air quality display to read abnormally or disappear, and disables the automatic fresh air/recirculation switching function. It does not affect the vehicle powertrain or core thermal management functions.B173A1ADTC B173A1A indicates the right middle-row side airbag (typically located on the side of the right second-row seat or inside the C-pillar trim panel) igniter circuit resistance measures 0 Ω. In the Supplemental Restraint System (SRS), normal airbag igniter resistance ranges between 2.0 and 5.0 Ω. A resistance of 0 Ω indicates a short to ground or a short between circuit wires, preventing the Airbag Control Unit (ACU) from establishing a normal monitoring circuit. This safety-critical fault prevents the airbag from deploying during a collision, continuously illuminates the instrument panel SRS warning lamp, and may force the entire airbag system into fail-safe mode.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Qin Plus →Qin Plus overview →
Data confidence: Official This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.