AU
B170D1B

This DTC indicates the SRS (Supplemental Restraint System) control module detects an open circuit in the Curtain Shield Airbag RH ignition circuit — Seal 6 EV

Safety System

This DTC indicates the SRS (Supplemental Restraint System) control module detects an open circuit in the Curtain Shield Airbag RH ignition circuit.

Specifically, the ACU (Airbag Control Unit) continuously monitors the circuit resistance of each airbag inflator.

When the Curtain Shield Airbag RH resistance exceeds the normal range (typically >10Ω or infinite), the ACU registers a 'disconnected' state.

This fault prevents the Curtain Shield Airbag RH from deploying during a side impact or rollover, severely compromising occupant head protection, and continuously illuminates the instrument cluster airbag fault warning lamp.

The B170D1B fault code on the Seal 6 EV indicates an open circuit in the right curtain shield airbag ignition circuit. This is a medium-severity SRS fault because the right curtain airbag may not deploy in a side impact or rollover. Common causes include a loose or poor-contact yellow airbag connector near the headliner/B-pillar, or a failed airbag igniter. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
3
Cases Logged
5
Causes
Likely Causes — Seal 6 EV
  • 1Right curtain airbag wiring harness connector loose or poor contact (commonly the yellow plug on the right side of the headliner or B-pillar)
  • 2Right curtain airbag module internal igniter open circuit (broken internal spiral coil or propellant failure causing abnormal resistance)
  • 3Physical damage to the wiring harness (frequent door opening and closing causing fatigue breakage of the harness inside the B-pillar, or accidental harness damage during headliner repair)
  • 4Oxidized or backed-out terminals at the SRS control module (ACU) connector, causing loss of communication with the right curtain airbag.
  • 5Vehicle water ingress or a high-humidity environment causes internal corrosion in the curtain airbag connector, creating excessive contact resistance and triggering an open circuit.
What To Do
  • 1
    Safety preparation: Disconnect the low-voltage battery negative terminal and wait at least 3 minutes to fully discharge the SRS backup power supply and prevent accidental airbag deployment.
  • 2
    Visual inspection: Remove the right A-pillar, B-pillar, and right roof trim panels. Verify the yellow connector (usually marked 'CSAB RH' or similar) is fully locked. Inspect the terminals for oxidation, burn marks, or signs of water ingress.
  • 3
    Resistance measurement: Disconnect the right curtain airbag connector. Use a multimeter to measure the resistance between the terminals on the curtain airbag side. The normal value is 2.0-5.0 Ω. If the reading shows infinity (OL) or >10 Ω, confirm the curtain airbag is damaged and replace it.
  • 4
    Wiring harness continuity test: Measure continuity of the two wires between the curtain airbag connector and the SRS ECU (< 1 Ω), and measure insulation to body ground and the 12V power supply (> 10 MΩ) to check for intermittent open circuits.
  • 5
    Reset verification: Reconnect all connectors (listen for the locking 'click'), restore power, clear the fault code using VDS or a Launch diagnostic tool, perform the 'SRS system self-check' or 'collision output check', and confirm B170D1B does not return and the warning light turns off.
Real-World Cases
BYD DTC AI Analysis

BYD E2 right-side curtain airbag intermittent fault after water wading

✓
A 2019 BYD E2 presented with the SRS warning light illuminated after driving through water during a heavy rain. Scanning revealed fault code B170D1B. Removing the right B-pillar trim showed water stains and green copper corrosion inside the curtain airbag harness connector. The technician cleaned the terminals with electrical contact cleaner, applied conductive protectant, reconnected the plug, and wrapped it with waterproof tape. The technician also checked the drain holes for blockages. The fault cleared following the repair.
BYD DTC AI Analysis

Qin EV curtain airbag not connected after accident repair

✓
A 2019 BYD Qin EV was hit on the right rear. After a third-party shop replaced the right side panel, the airbag warning light came on. Diagnosis found the technician didn't fully insert the yellow curtain airbag connector when fitting the new headliner – it was only pushed in halfway, causing poor contact. Fix: Reseated the connector so the locking tab fully engaged, performed 'Airbag Module Recalibration' under 'Configuration and Settings' with a diagnostic scanner, and cleared the fault codes.
BYD DTC AI Analysis

Chafed E3 wiring harness caused open circuit in right curtain airbag

✓
2020 BYD E3 at 80,000 km: Intermittent airbag warning light and DTC B170D1B. Found the lower B-pillar wiring harness at the door hinge had insulation damage from prolonged friction, the internal wires broken but still making intermittent contact. Repair: cut out the damaged section, soldered in colour-matched high-temperature wire, added corrugated tubing for protection, and rerouted the harness away from metal edges.
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.