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B17301A

DTC B17301A indicates the Supplemental Restraint System (SRS) detected a resistance of 0 ohms in the left middle-row (second-row left-side) side airbag module firing circuit, indicating a hard short circuit — Qin Plus

Safety System

DTC B17301A indicates the Supplemental Restraint System (SRS) detected a resistance of 0 ohms in the left middle-row (second-row left-side) side airbag module firing circuit, indicating a hard short circuit.

Normal airbag squib resistance is between 2.0 Ω and 4.0 Ω.

A resistance of 0 ohms indicates current passes directly through the circuit without load.

Possible causes include an internal short circuit in the airbag ignition wire, a wiring harness short to ground, a short circuit between connector terminals, or a fault in the SRS control unit (ACU) internal detection circuit.

Upon detecting this fault, the ACU immediately illuminates the airbag warning lamp and disables the left middle-row side airbag to prevent accidental deployment from the short circuit.

Consequently, the airbag will fail to deploy during a collision, posing a severe safety hazard.

5
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Left middle-row side airbag module internal igniter short circuit: Moisture, aging, overload, or manufacturing defects break down the insulation between the positive and negative terminals of the internal airbag igniter wire, causing a short circuit.
  • 2Seat wiring harness worn and shorted to ground: During middle-row seat fore/aft sliding or backrest angle adjustment, the airbag wiring harness rubs against the seat frame, slide rail, or spring, damaging the insulation layer and shorting to body ground.
  • 3Connector fault: Water ingress, bent pins, detached terminals, foreign objects, or oxidation in the yellow airbag-specific connector (usually containing a shorting bar) located under the seat or inside the C-pillar trim panel, causing a short circuit between the terminals.
  • 4SRS control unit (ACU) internal fault: Damage to the ACU crash sensor interface circuit or ignition driver circuit triggers a false short-circuit fault (actual external wiring is normal).
  • 5Improper modification or repair: During seat removal/installation, leather retrimming, or installation of seat cushions or floor mats, retaining clips or cable ties crush or pierce the airbag wiring harness, causing a short circuit.
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 system energy storage capacitor. This prevents accidental airbag deployment and personal injury.
  • 2
    Fault confirmation: Use the VDS2000 or Launch X431 diagnostic tool to read the fault code. Confirm B17301A is a current fault (Active), not a history fault, and record the resistance value and ambient temperature from the freeze frame data.
  • 3
    Visual inspection: Check the side of the left middle-row seat (second row, left side) for signs of impact, water ingress, or modification. Check the airbag marking location (usually on the side of the backrest or the C-pillar).
  • 4
    Connector inspection: Remove the seat side trim panel or lower C-pillar trim panel. Locate the yellow airbag-specific connector (usually containing a shorting bar/shorting spring) and check for looseness, water ingress, oxidation, or bent or deformed pins.
  • 5
    Resistance measurement: Disconnect the airbag module connector. Use a multimeter to measure the resistance on the airbag module side (standard value: 2.0-4.0Ω). A reading of 0Ω or close to 0Ω indicates an internal short circuit in the airbag module. Replace the module.
  • 6
    Harness insulation check: If airbag module resistance is normal, measure harness-side resistance to ground (must be infinite). If continuity exists (0Ω), the harness has a short to ground. Trace the circuit to locate the fault, focusing on wear points at the seat slide rails, hinges, and mounting brackets.
  • 7
    Shorting bar function test: Check the connector shorting bar for binding or deformation. Verify the shorting bar reliably short-circuits the terminals with the plug disconnected (to prevent accidental deployment from static electricity) and springs fully open with the plug connected.
  • 8
    Repair and Replacement: Repair the damaged wiring harness (apply double-layer heat-shrink tubing or replace the entire wiring harness) or replace the faulty airbag module. Note: Record the old and new part numbers when replacing the airbag module. Some models require coding.
  • 9
    System reset: Reconnect all connectors, connect the battery, use the diagnostic tool to clear the fault code, and perform an SRS system self-diagnosis (including circuit resistance monitoring and system check).
  • 10
    Function verification: Verify the instrument cluster airbag warning lamp turns off after the self-check (approximately 6 seconds). Read the data stream to confirm the left middle-row side airbag resistance returns to the normal range of 2.0-4.0 Ω. Adjust the seat forward and backward to ensure no interference.
Real-World Cases
BYD DTC AI Analysis

Worn wiring harness on middle row seat caused short circuit in Song MAX

✓
Model: 2019 BYD Song MAX, 32,000 km. Issue: Airbag warning light stayed on constantly. VDS scan retrieved DTC B17301A (left second-row side airbag resistance 0 Ω). Repair: Removed the left second-row seat. Found the airbag wiring harness sheath chafed through at the seat rail, allowing the copper wires to touch the seat frame and short to ground. Repaired the harness with heat-shrink tubing and re-secured the routing. Cleared the DTCs – fault resolved.
Original source ↗
BYD DTC AI Analysis

Qin EV left middle row side airbag module internal short circuit

✓
Vehicle: 2020 BYD Qin EV. Symptom: Airbag warning light on, DTC B17301A. Disconnected the left centre-row seat side airbag connector and directly measured resistance between the airbag module pins: 0.2 Ω (normal 2–4 Ω). This indicated an internal short in the igniter. Replaced the left centre-row side airbag module. Resistance returned to 3.1 Ω and the fault cleared. Repair cost around 1200 yuan.
Original source ↗
BYD DTC AI Analysis

Song DM: Oxidised connector under seat causing short circuit

✓
Model: 2018 BYD Song DM. Symptom: Airbag warning light stays on after startup. VDS read DTC B17301A. Diagnostic steps: Inspected the yellow airbag connector beneath the left middle-row seat. Found green oxidation and slightly deformed pins inside, causing a micro-short between terminals. Cleaned the connector terminals with electronic contact cleaner, straightened the pins, and applied conductive paste. Cleared the fault codes and monitored the vehicle for one week — no recurrence.
Original source ↗
BYD DTC AI Analysis

Aftermarket seat modification crushed airbag wiring harness on Han EV

✓
Vehicle: 2021 BYD Han EV, 8 months from new. The airbag warning light came on suddenly. The dealership diagnosed DTC B17301A. A subsequent workshop inspection found that the owner's seat cover retaining clips had crushed the left rear side airbag harness, causing a short between the positive and negative wires. The workshop re-wrapped the harness and adjusted the clip positions. Total repair cost: 50 yuan.
Original source ↗
BYD DTC AI Analysis

e5 450 wiring harness improperly secured, chafed and shorted

✓
Vehicle: 2017 BYD e5 450. The airbag warning light on the instrument cluster stayed on. The diagnostic scanner read DTC B17301A (left centre row side airbag circuit resistance 0 ohms). Removed the left centre row seat and found the airbag wiring harness unsecured at the seat rail. Long-term friction wore through the insulation, causing a short to ground. Repaired the damaged harness and re-routed and secured the wiring as per the workshop manual to prevent contact with moving parts.
Original source ↗
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.