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B17081A

DTC B17081A indicates the LHS Curtain Shield Airbag ignition circuit resistance is 0 ohms, representing a short circuit — Seal 6 EV

Safety System

DTC B17081A indicates the LHS Curtain Shield Airbag ignition circuit resistance is 0 ohms, representing a short circuit.

In the BYD SRS (Supplemental Restraint System), normal curtain airbag inflator resistance is 1.8-2.5 Ω.

A 0 Ω resistance indicates a short to ground in the ignition wiring between the SRS control unit and the LHS curtain airbag, or an internal short circuit within the inflator.

This fault prevents the LHS curtain airbag from deploying during a collision.

The control unit disables the shorted circuit to prevent accidental deployment and illuminates the airbag warning lamp.

The short circuit can trigger a protective lockout of the SRS control unit, which in severe cases affects the normal operation of the entire airbag system.

The B17081A fault code on the Seal 6 EV indicates a short circuit in the left-hand curtain shield airbag ignition circuit, with resistance reading 0 ohms instead of normal range. Severity is medium because the left curtain airbag may not deploy and the SRS warning light may be on. Common causes include a shorted airbag inflator or damaged wiring in the pillars or headliner. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
5
Cases Logged
5
Causes
Likely Causes — Seal 6 EV
  • 1Internal short circuit in the left side curtain airbag inflator: Moisture, aging, or manufacturing defects cause the igniter bridge wire inside the curtain airbag assembly to short circuit between the positive and negative terminals.
  • 2Wiring harness chafed and shorted to ground: Long-term vibration and friction damage the wiring harness insulation in the A-pillar, B-pillar, or headliner, causing a short circuit to the vehicle body metal.
  • 3Connector fault: Water ingress, corrosion, or bent pins causing a short circuit in the curtain airbag connector (usually located in the headliner or C-pillar).
  • 4SRS control unit internal drive circuit fault: Breakdown of the internal ignition drive transistor caused a short circuit.
  • 5Improper repair work: During previous headliner removal and installation, glass replacement, or A-pillar trim removal and installation, a tool pierced the curtain airbag wiring harness, or the connector failed to seat correctly.
What To Do
  • 1
    Safety preparation: Disconnect the 12V battery negative terminal and wait at least 3 minutes to fully discharge the SRS capacitor. Disable the high-voltage system (if applicable).
  • 2
    Initial diagnosis: Use a dedicated diagnostic tool (such as VDS2000/3000) to read freeze frame data and confirm the environmental conditions when the fault occurred. Clear the fault code, cycle the ignition, and observe if it is a current fault (Current DTC).
  • 3
    Circuit measurement: Disconnect the SRS ECU and left curtain airbag connectors. Use a multimeter to measure the curtain airbag-side wiring harness resistance to ground and check if it is 0 Ω. Measure the curtain airbag resistance (specification: 1.8-2.5 Ω). If the resistance is 0 Ω, replace the curtain airbag assembly.
  • 4
    Wiring harness inspection: Check the headliner wiring harness (especially the A-pillar to C-pillar section) for wear and crush marks. Check connector seals and pin condition. Measure the wiring harness insulation resistance to ground; it must be greater than 1MΩ.
  • 5
    ECU check: If the wiring harness and curtain airbag are normal, measure the output at the corresponding SRS ECU pin. If the output still indicates a short circuit, replace the SRS control unit.
  • 6
    Repair verification: After repairing the short circuit, use a 2Ω substitute resistor (special test tool) to simulate the curtain airbag and confirm the fault code clears and the system returns to normal. Finally, connect the actual curtain airbag and complete 3 ignition cycle self-checks to confirm the system outputs no fault codes.
Real-World Cases
BYD DTC AI Analysis

Left curtain airbag inflator internal short circuit case

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Model: BYD Qin EV 2019. Symptom: Instrument panel airbag warning light stays on constantly; read DTC B17081A. Diagnosis: Disconnected the battery, removed the left curtain airbag connector, measured resistance across the airbag terminals: 0.2 Ω (normal: approx. 2 Ω), confirming an internal short in the curtain airbag. Fix: Replaced the left curtain airbag assembly, rewound the airbag using special tools to prevent wrinkles after installation, and cleared the fault.
BYD DTC AI Analysis

Headlining wiring harness chafed, short to ground.

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Model: BYD E2 2019. Symptom: Airbag warning light illuminated after driving over rough roads, DTC B17081A stored. Diagnosis: Checked curtain airbag unit — normal. Traced the roof wiring harness and found a loose retaining clip above the A-pillar. The harness had chafed against the metal bracket, damaging the insulation and exposing copper wires that shorted to body. Repair: Repaired the damaged harness by wrapping with insulation tape and covering with corrugated sleeving. Re-secured harness routing and ensured adequate clearance from sharp edges.
BYD DTC AI Analysis

C-pillar connector water ingress corrosion

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Model: BYD E3 2020. Symptoms: Airbag warning light illuminated after rain; intermittent DTC B17081A. Diagnosis: Inspected the left curtain airbag C-pillar connector (located within the trim panel above the rear seat). Found the connector seal degraded and pins showing green copper corrosion, causing a short circuit between terminals. Fix: Cleaned the connector pins using electrical contact cleaner, replaced the seal, and applied waterproof silicone grease to the connector to ensure waterproof performance.
BYD DTC AI Analysis

SRS control unit internal driver fault

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Model: BYD Qin EV 2019. Symptoms: The fault persisted after multiple left curtain airbag and wiring harness replacements. DTC B17081A was current and could not be cleared. Diagnostic process: Disconnected the curtain airbag and wiring harness, then directly measured the corresponding output pins on the SRS ECU. Resistance to ground was 0 Ω, confirming a short circuit in the control unit's internal ignition drive circuit. Solution: Replaced the SRS control unit (required re-coding of vehicle configuration and crash sensor calibration). Fault resolved.
BYD DTC AI Analysis

Improper removal and installation pinched the wiring harness, causing a short circuit.

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Vehicle: BYD E2 2019. Symptoms: After the dealership replaced the headliner, fault code B17081A appeared upon delivery. Diagnosis: Inspection revealed the A-pillar trim clip pinched the left curtain airbag wiring harness during A-pillar trim installation, causing an internal short circuit. Resolution: Repaired the damaged harness by cutting out the affected section and soldering in an extension, rerouted the harness to clear the trim clip mounting points, and reinstalled the A-pillar trim.
Other Seal 6 EV 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.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.B1109DTC B1109 indicates an open circuit in the communication line between the air conditioning system PM2.5 air quality sensor (dust concentration sensor) and the air conditioning control unit (AC ECU), or an open circuit within the sensor internal circuitry. Typically located in the air conditioning intake duct, this sensor monitors real-time PM2.5 particle concentration inside and outside the vehicle. It provides data to the automatic air conditioning system for intelligent switching between fresh air and recirculation modes and for controlling the air purification device. During an open circuit fault, the AC ECU cannot receive the air quality signal, triggering the system fail-safe mode. Symptoms typically include failure of the automatic recirculation function, abnormal air purification indicator light operation, or abnormal air quality data displayed on the air conditioning panel. Severe cases may compromise the cabin environment control strategy, but do not directly affect vehicle driving safety.B1737DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive). The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω). If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power. This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current. In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.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 Seal 6 EV →Seal 6 EV 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.