AU
B1736

DTC B1736 indicates the Supplemental Restraint System (SRS) detects a short to body ground in the igniter circuit of the right second-row seat side airbag (Side Airbag Module, located on the side of the right second-row seat) — Atto 8

Safety System

DTC B1736 indicates the Supplemental Restraint System (SRS) detects a short to body ground in the igniter circuit of the right second-row seat side airbag (Side Airbag Module, located on the side of the right second-row seat).

Under BYD DTC coding rules, B1736 serves as the general identifier for this fault type.

A specific short to ground typically corresponds to B173611 (hexadecimal 11 indicates a short to ground).

This fault means the resistance between the two airbag igniter terminals, or between a terminal and the vehicle body, drops abnormally low (typically below 1.0 Ω).

The SRS ECU determines this is a short circuit.

This fault causes the airbag warning lamp to remain illuminated.

The system automatically cuts off the affected airbag circuit to prevent accidental deployment.

In a collision, the airbag may fail to deploy normally, severely compromising occupant safety.

Applicable models primarily include the Tang, Song MAX, and other 6-seat or 7-seat vehicles equipped with second-row side airbags.

The B1736 fault code on the Atto 8 indicates a high-severity SRS fault: a short to body ground in the right second-row seat side airbag igniter circuit. The airbag warning light may stay on, and the affected airbag may not deploy in a crash. Common causes include damaged under-seat wiring near the seat rail or moisture and corrosion in the yellow airbag connector. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Atto 8
  • 1Wiring harness wear at the seat slide rail: Frequent forward and backward adjustment of the right middle-row seat rubs the underlying yellow airbag wiring harness (typically located inside the seat rail) against the metal bracket. This friction damages the insulation and shorts the copper wire to body ground.
  • 2Connector water ingress and oxidation: During vehicle wading or interior cleaning, the under-seat airbag connector (yellow waterproof connector) fails to seal properly. Moisture enters, causing a short circuit between terminals or to ground. This is especially common in humid southern regions.
  • 3Improper seat removal and installation: Pulling the wiring harness during seat removal for repairs or when installing floor mats or seat covers causes the airbag connector to loosen, pins to bend and contact the vehicle body, or metal clips to pierce the harness insulation.
  • 4Internal airbag module fault: A manufacturing defect or long-term vibration causes an internal short circuit in the igniter squib inside the right middle-row side airbag assembly. Measuring the module connector shows an abnormal resistance near 0Ω (normal: 2.0-3.0Ω).
  • 5Wiring harness retaining clip failure: The original wiring harness retaining clip detaches, causing the harness to continuously rub against the metal edge of the seat frame during seat adjustment, eventually wearing through the insulation and shorting to ground.
What To Do
  • 1
    Safe power isolation and waiting: Turn off the ignition switch, disconnect the negative battery cable, and wait at least 3 minutes (or 5 minutes per the repair manual) to fully discharge the internal SRS ECU capacitor and prevent accidental airbag deployment.
  • 2
    Preliminary visual inspection: Remove the right middle-row seat (second row, right side). Inspect the yellow wiring harness corrugated conduit under the seat, inside the seat rail, and on the side of the backrest for wear, cuts, or crush marks. Inspect the connector for looseness, water ingress, or green corrosion.
  • 3
    Harness continuity test: Disconnect the right middle row side airbag connector (located under the seat or at the backrest connection). Use a multimeter on the resistance setting to measure the resistance between each harness-side terminal and body ground. Normal resistance is infinity (OL). If the reading is 0-5Ω, locate the short to ground.
  • 4
    Airbag module body test: After verifying the wiring harness is normal, measure the resistance between the two pins on the airbag module. The normal range is 2.0 ± 0.3 Ω (refer to the specific vehicle repair manual). If the resistance is close to 0 Ω, the airbag module has an internal short circuit. Replace the entire side airbag assembly.
  • 5
    Wiring harness repair and protection: If the wiring harness is damaged, open the corrugated conduit and wrap the damaged area with multiple layers of waterproof insulating tape (such as 3M Scotch 2228). Re-secure the wiring harness and maintain a minimum clearance of 20mm from the seat frame to prevent further abrasion.
  • 6
    System reset and verification: Reconnect all connectors and the battery. Use the diagnostic tool to clear the fault code. Perform the 'SRS system self-check' or 'configuration reset' (some models require coding matching after airbag replacement). Confirm B1736 does not return and the airbag warning light turns off.
Real-World Cases
BYD DTC AI Analysis

Song MAX: Right middle row side airbag wiring harness worn through at guide rail, causing short circuit

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Vehicle: 2020 BYD Song MAX DM (6-seater) Symptom: Dashboard airbag warning light stayed on constantly. Diagnostic scan retrieved DTCs B1736/B173611. Repair: Found the yellow wiring harness beneath the right-hand middle-row seat pinched at the front of the seat slide rail. Repeated seat adjustments had worn through the insulation, leaving the bare copper wires touching the metal rail directly. Repaired the two damaged wires, wrapped them with double-layer waterproof insulation tape, rerouted the harness, and fitted abrasion-resistant corrugated tubing. Ensured the harness had enough slack to avoid future interference with the slide rail. Resolution: Fault cleared.
BYD DTC AI Analysis

Tang DM: Right middle-row side airbag connector shorted due to water ingress after wading

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Vehicle: 2021 Tang DM (7-seater). Symptom: After heavy rain, vehicle drove through floodwater; next day, airbag warning light illuminated on startup, logging DTC B1736. Repair: Found visible water droplets inside the airbag plug beneath the right-hand second-row seat (yellow 2-pin plug). Terminals were oxidised and blackened. Measured resistance between plug terminals and ground: 0.3 Ω. After removing water from the plug, cleaned terminals with electrical contact cleaner, applied conductive grease, and replaced the waterproof seal. Fault resolved. Recommendation: Check connector sealing on vehicles from the same production batch.
BYD DTC AI Analysis

Replaced right centre row side airbag module on BYD Yuan EV due to internal short circuit

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Vehicle: 2019 Yuan EV535. Issue: No accident history, but the airbag warning light suddenly illuminated with DTC B1736. Repair: Disconnected the airbag connector beneath the seat and measured the harness-side resistance to ground — normal (infinite). Measured the resistance between the two terminals of the airbag module (seat side airbag assembly) connector: 0.8 Ω (spec: 2.0 Ω), indicating an internal igniter short circuit. Replaced the right middle-row side airbag module (part number: ...), performed SRS system configuration write, and cleared the fault. Analysis of the old part found the internal igniter filament had fractured and shorted to ground due to a material defect.
BYD DTC AI Analysis

Rear seat removal and refitting on a Qin Pro caused the wiring harness clip to detach, resulting in a short circuit.

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Vehicle: 2020 Qin Pro Super Edition. Symptom: After the customer fitted full-surround seat covers, the airbag warning light came on with DTC B1736. Diagnosis: Inspection found the original harness retaining clip on the right middle-row seat had snapped during removal/refitting, letting the airbag harness hang and chafe against the seat height adjustment linkage. The damaged insulation caused a short to earth. Repair: Repaired damaged wiring and resecured the harness to the seat frame mounting holes with cable ties, preventing interference with moving parts.
Other Atto 8 Fault Codes
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.B110A02DTC B110A02 indicates the thermal management master control unit (HVAC ECU) or body control module (BCM) failed to receive valid CAN data frames from the PM2.5 air quality sensor over consecutive communication cycles (typically 500ms per cycle). The sensor typically mounts at the HVAC unit air inlet or behind the glove box and transmits real-time particulate concentration data (unit: μg/m³) to the HVAC controller via the CAN bus. The fault is essentially a communication link layer timeout. Potential causes include physical layer wiring faults, sensor power supply failures, sensor internal MCU lockup, or CAN network topology damage. Although this non-critical fault does not directly affect driving safety, it disables the intelligent air purification strategy and the automatic fresh air/recirculation switching function. In extreme cases, it triggers a thermal management system degraded mode, limiting compressor power or fixing the air flap position.B110B07This fault code indicates abnormal operation of the internal air pump (sampling pump) in the PM2.5 air quality detection module. The PM2.5 detector uses the laser scattering principle to measure particulate concentration and requires a built-in air pump to draw ambient air into the detection chamber at a constant flow rate. The ECU sets this code when it detects an open or short in the air pump drive circuit, abnormal current (stall or free-running), or abnormal speed feedback. This fault causes the automatic air conditioning system to lose air quality sensing capability, preventing automatic switching between fresh air and recirculation modes. The instrument cluster air quality display may show '--' or a fixed value, but the fault does not affect the vehicle powertrain or basic air conditioning cooling and heating functions.B173CDTC B173C indicates the Supplemental Restraint System (SRS) detects the Right Second Row Side Airbag squib circuit resistance exceeds the calibrated threshold (typically >4.5Ω). This fault is an active diagnostic result of the SRS system, indicating a high-resistance condition in the circuit between the Airbag Control Unit (ACU) and the airbag module. Causes for excessive resistance include increased contact resistance, a partially broken wiring harness, terminal oxidation, or an aging squib wire inside the airbag module. This fault causes the system to mark the airbag circuit as 'unreliable', meaning the airbag may fail to deploy during a collision. The fault typically illuminates the instrument cluster airbag warning light (SRS light) continuously, and some models also sound a warning buzzer.
Common problems reported for Atto 8 →Atto 8 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.