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B1752-00

DTC B1752-00 indicates the right rear side airbag igniter circuit is shorted to vehicle power (B+) — Qin Plus

Safety System

DTC B1752-00 indicates the right rear side airbag igniter circuit is shorted to vehicle power (B+).

In the SRS (Supplemental Restraint System) circuit architecture, the airbag igniter is a low-impedance (nominal 2-5Ω) resistance wire.

Normally, the SRS control unit uses an internal boost circuit to supply a momentary high current (approx. 1-3A) to deploy the airbag during a collision.

Detecting a short to the 12V power supply in the igniter harness indicates an abnormal high-potential path in the circuit.

This creates two risks: first, continuous power supply may cause accidental airbag deployment without a collision (although modern SRS controllers typically feature short-circuit protection); second, during an actual collision, the external power short prevents the control unit from forming an effective current loop to deploy the airbag, disabling the safety function.

Consequently, the SRS control unit immediately illuminates the airbag warning lamp, stores this DTC, disables the right rear side airbag and related linked protection functions, and enters fail-safe mode.

The B1752-00 fault code on the Qin Plus indicates a high-severity short to battery power in the right rear side airbag igniter circuit. This can disable the airbag and may create an unintended deployment risk, so the SRS warning light will stay on. Common causes include damaged wiring near the rear seat hinge or harness pinching from seat movement or modifications. Visit an authorised dealer for inspection and repair. Typical repair cost data is available.
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Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Repeated bending and wear at the seat frame hinge damages the right rear seat side airbag wiring harness insulation, causing a short circuit to the seat heating or adjustment motor power wire.
  • 2During frequent rear seat folding/reclining or seat cover modification, seat rails or metal frames pinch the wiring harness, damaging the wire insulation and causing a short to power.
  • 3Water ingress and corrosion at the airbag connector (yellow plug) in the right rear C-pillar or under the seat (commonly due to leaking aged sunroof drain tubes or vehicle wading) causes electrolyte conduction between terminals, creating a short circuit.
  • 4Power transistor breakdown in the internal ignition drive circuit of the airbag control unit (SRS ECU) causes a continuous 12V output to the igniter circuit.
  • 5During vehicle accident repair or interior trim removal/installation, missing wiring harness retaining clips cause the harness to shift, rub against sharp metal body edges, sustain damage, and contact a power wire.
What To Do
  • 1
    Safety preparation: Set the power switch to OFF, disconnect the negative battery terminal, and wait at least 3 minutes (to fully discharge the SRS energy storage capacitor). Never measure the airbag circuit while powered on.
  • 2
    Visual inspection: Remove the right rear seat and lower C-pillar trim panel. Check the right rear side airbag module connector (usually located on the side of the seat back or below the C-pillar) for looseness, water ingress, corrosion, or foreign objects. If necessary, clean with electrical contact cleaner and blow dry.
  • 3
    Circuit measurement: Disconnect the airbag module connector. Use a high-impedance multimeter to measure the voltage to ground at the harness-side terminal. Normal voltage is less than 1 V; if 12 V is present, confirm a short to power in the circuit. Measure the resistance to ground at the terminal. Normal resistance is greater than 1 MΩ.
  • 4
    Fault isolation: If measurement is abnormal, carefully inspect the yellow wiring harness sleeve routing, focusing on wear-prone areas such as the seat folding mechanism, guide rail mounting points, and C-pillar sheet metal holes. Repair damaged wiring harnesses (re-wrap or replace the harness section). Maintain at least 20mm clearance from power cables.
  • 5
    Component replacement verification: If the wiring harness is normal, replace the original airbag module with a 2-3Ω non-inductive resistor (or dedicated airbag simulator). Reconnect the circuit, power on the vehicle, clear the fault code, and perform an SRS self-check. If the fault disappears, the airbag module has an internal short circuit. Replace the right rear side airbag module. Store the new part flat and away from heat sources.
  • 6
    System reset: After confirming fault resolution, refit all connectors and trim panels, connect the battery, clear the fault codes using the BYD dedicated diagnostic tool (VDS or EDS), and perform the 'SRS system self-learning' and 'crash sensor configuration' procedures.
  • 7
    Function verification: Set the power mode to ON and verify the instrument cluster airbag warning light turns off after the 6-second self-check. Perform a road test, simulate bumpy road conditions, and confirm the fault code does not recur.
Real-World Cases
BYD DTC AI Analysis

Frequent folding of the right rear seat caused the wiring harness to wear through and short circuit.

✓
A 2018 BYD Qin EV450 with 80,000 km showed an airbag warning light on the dash. VDS pulled fault code B1752-00. The owner said they often used the car for hauling cargo, keeping the right rear seat folded down for long periods. Removing the seat revealed the side airbag wiring harness insulation had completely worn through at the seat frame hinge, exposing copper wire that shorted against the seat heater pad power line. Repair: replaced the damaged wiring section, fitted abrasion-resistant corrugated tubing, re-routed the harness, and added retaining clips to prevent flexing during seat movement. Fault resolved.
BYD DTC AI Analysis

C-pillar water leak caused airbag connector corrosion and short circuit

✓
2017 Qin 100 airbag warning light remained on after heavy rain, with DTC B1752-00. Found water inside the right rear C-pillar trim. The rear sunroof drain hose connector had deteriorated and detached, allowing rainwater to run down the C-pillar. The right rear side airbag connector (yellow) below the C-pillar had corroded from water ingress; oxide layers and electrolyte on the terminals caused a short to power. Repair: Unclogged and replaced the sunroof drain hose, removed water from the C-pillar, thoroughly cleaned the connector with electrical contact cleaner and applied conductive grease, blow-dried and left for 24 hours, then reinstalled and road tested. Fault resolved.
BYD DTC AI Analysis

Airbag module internal short circuit false alarm.

✓
No collision history. DTC B1752-00 sets intermittently and returns days after clearing. Disconnected the airbag module connector and measured the harness side – voltage <0.1V, resistance to ground >10MΩ. Substituted a 2.5Ω resistor for the airbag module to simulate the load and monitored continuously for one week without fault recurrence. Found insulation deterioration on the igniter resistor wire inside the right rear side airbag module, causing an internal short to the capacitor terminal. Replaced with a genuine airbag module (part number matches VIN), performed SRS configuration, and resolved the fault completely.
BYD DTC AI Analysis

Seat removal and refitting pinched the wiring harness, causing a short circuit.

✓
The vehicle developed DTC B1752-00 the day after an unauthorised repair shop replaced the right rear seat leather cover. Inspection at the dealership revealed that during seat installation, the technician had failed to properly clip the airbag wiring harness into the retention slot on the seat frame. The seat rails pinched the harness, and the metal edge cut the insulation during electric seat adjustment, causing a short to the seat motor power supply wire. Repair procedure: Rerouted the harness into the dedicated wiring channel, wrapped the damaged section with felt tape (copper core unaffected), fitted abrasion-resistant sleeving, and reinstalled the retaining clips. Cleared the fault code and verified normal operation through multiple seat adjustment cycles. Fault resolved.
BYD DTC AI Analysis

SRS control unit internal driver circuit fault

✓
After ruling out the wiring harness and airbag module, the fault remained. I measured a constant 12V at the SRS ECU drive terminal for the right rear side airbag (normally 0V; it should supply voltage only upon crash trigger). I removed the SRS control unit (under the centre console) and found the power MOSFET in the internal ignition drive circuit had short‑circuited, sending constant voltage to the igniter circuit. Since the control unit is a safety component and cannot be serviced separately, I replaced the SRS control unit assembly, carried out online coding (entering the vehicle VIN and configuration code), and calibrated the collision sensors to clear the fault.
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.