AU
B1713

DTC B1713 indicates the right curtain airbag igniter circuit resistance falls below the normal threshold set by the SRS control unit (typically 2 — Qin Plus

Safety System

DTC B1713 indicates the right curtain airbag igniter circuit resistance falls below the normal threshold set by the SRS control unit (typically 2.0-5.0Ω).

Low resistance (<2Ω or close to 0Ω) indicates a short circuit risk in the igniter circuit.

Potential causes include an internal short circuit in the curtain airbag, a wiring harness short to ground, or an abnormal internal driver circuit in the SRS ECU.

This fault forces the SRS system into fail-safe mode.

During a collision, the right curtain airbag may fail to deploy, or it may deploy unintentionally.

This constitutes a high-level safety fault.

4
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Internal short circuit in the right curtain airbag igniter: Aging, moisture ingress, or manufacturing defects reduce insulation between the squib terminals inside the curtain airbag, dropping resistance below 2Ω.
  • 2Wiring harness short to ground: A-pillar, B-pillar, or roof wiring harness wear during collision repairs, modifications, or long-term use shorts the igniter circuit to body ground.
  • 3Connector terminal short circuit: Water ingress, oxidation, or improper connection causes a short circuit between terminals in the right curtain airbag connector (usually located near the roof side rail or C-pillar).
  • 4Internal fault in the SRS control unit: Breakdown of curtain airbag drive circuit components inside the ACU (Airbag Control Unit) causes abnormal resistance readings.
  • 5Improper repair procedures: During headliner or side trim panel removal, tools crush the wiring harness causing insulation damage, or metal clips pierce the wiring harness causing a short circuit.
What To Do
  • 1
    Use VDS or a dedicated diagnostic tool to read the fault code. Confirm B1713 is a current fault (active), not a history fault. Record the freeze frame data.
  • 2
    Perform the safe power-down procedure: turn off the ignition switch, disconnect the battery negative terminal, and wait at least 90 seconds to fully discharge the SRS capacitor and prevent accidental airbag deployment.
  • 3
    Remove the right A-pillar trim, B-pillar trim, and rear section of the headliner to expose the right curtain airbag assembly and the yellow SRS connector (usually marked R-Curtain or R-SAB).
  • 4
    Visually inspect the wiring harness: check the yellow corrugated conduit for damage or scorch marks, and the connector for water ingress, corrosion, or bent pins.
  • 5
    Disconnect the right curtain airbag connector. Use a multimeter to measure the resistance between the airbag-side terminals. Standard resistance is 2.0-5.0Ω. If <2Ω, replace the curtain airbag assembly. Measure the harness-side insulation resistance to ground. Standard resistance is >1MΩ; otherwise, repair the wiring harness.
  • 6
    If the curtain airbag resistance is normal, check the wiring harness continuity from the SRS ECU to the curtain airbag. Use a multimeter to measure the resistance between the corresponding ECU connector pin and the curtain airbag connector; the resistance must be <1Ω. Measure the insulation to ground and power supply.
  • 7
    Jumper verification: Connect a 2-3Ω simulator resistor to the wiring harness in place of the curtain airbag. Restore power and read the fault code. If the fault clears, the curtain airbag is faulty. If the fault remains, check the ECU.
  • 8
    Replace the faulty component (curtain airbag, wiring harness, or SRS ECU), reconnect all connectors, and fully engage the yellow locking tab.
  • 9
    Connect the battery, turn the ignition switch to ON, and clear the fault code using the diagnostic tool. Perform the SRS system self-check (typically requires 10-30 seconds). Verify B1713 does not return and the airbag warning light turns off.
  • 10
    Perform a road test. If necessary, use a diagnostic tool to read the live data stream and verify the right curtain airbag resistance is within the normal range.
Real-World Cases
BYD DTC AI Analysis

BYD Tang DM right side curtain airbag connector shorted due to water ingress

✓
A 2021 Tang DM triggered DTC B1713 after driving through floodwater during heavy rain. Disassembly revealed the right-side C-pillar curtain airbag connector seal had deteriorated, allowing rainwater to seep in and short the terminals. Resistance measured only 0.8Ω. Cleaned the connector with electronic cleaner, replaced the seal, and applied conductive anti-corrosion compound. Fault resolved.
BYD DTC AI Analysis

Song MAX: Pinched wiring harness after accident repair caused low resistance.

✓
After a right-side collision repair, a 2019 Song MAX set DTC B1713. Inspection found the technician hadn't routed the curtain airbag harness correctly when reinstalling the headliner. The headliner's metal clips pinched and damaged the harness, causing a short to earth. Repair: repaired the harness (3 wires with damaged insulation), re-routed it, and fitted protective sleeving. Fault cleared.
BYD DTC AI Analysis

BYD Yuan EV – Curtain Airbag Igniter Internal Fault Replacement Case

✓
A Yuan EV535 developed intermittent DTC B1713 after 40,000 km. The fault came and went. After disconnecting power, measured the right curtain airbag resistance; it fluctuated between 1.2 and 2.5 ohms (spec: 2.3±0.3 ohms). Determined that an ageing internal igniter in the curtain airbag was causing the unstable resistance. Replaced the right curtain airbag assembly (part number...), performed programming and matching, and the fault has not recurred.
BYD DTC AI Analysis

Qin Pro SRS ECU internal driver circuit fault

✓
2020 Qin Pro repeatedly logged DTC B1713. Replacing the right side curtain airbag and wiring harness did not fix the fault. Checked the ECU output waveform with an oscilloscope and found it abnormal. Diagnosis: component breakdown in the right curtain airbag drive circuit inside the SRS control unit. Repair: replaced the SRS control unit (VIN and configuration parameters must be updated at the same time). After online matching, the system returned to normal.
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.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.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.B110AThis DTC indicates interrupted CAN bus communication or abnormal data between the air conditioning control unit (ACU) and the PM2.5 air quality sensor. The PM2.5 sensor monitors particulate concentration inside and outside the vehicle and provides the basis for purification control in the automatic air conditioning system. The ACU triggers this fault if it fails to receive a valid CAN message from the sensor within the specified period (usually 100-500 ms), if message verification fails, or if the signal frame times out. Although this fault does not affect vehicle driving safety, it disables the automatic air purification function. The air conditioning system cannot automatically switch between recirculation and fresh air modes or activate the air purification mode based on air quality. A persistent fault may restrict the thermal management strategy.
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.