AU
B1751-00

B1751-00 is a Supplemental Restraint System (SRS) hard fault code indicating a short circuit to body ground (GND) in the right rear seat side airbag squib circuit (typically integrated into the seat backrest or C-pillar trim) — Seal U

Safety System

B1751-00 is a Supplemental Restraint System (SRS) hard fault code indicating a short circuit to body ground (GND) in the right rear seat side airbag squib circuit (typically integrated into the seat backrest or C-pillar trim).

The SRS ECU internal detection circuit continuously monitors the airbag squib circuit resistance (normal range: 2.0-3.0 Ω; 1.6-2.1 Ω on some models).

The ECU registers a short to ground when it detects circuit resistance to ground below 1.0 Ω (near 0 Ω).

This fault causes the following: 1) The affected airbag fails to deploy during a collision, losing its protective function. 2) The SRS enters fail-safe mode, which may restrict seat belt pretensioner operation. 3) The instrument panel airbag warning light remains illuminated, indicating a critical safety hazard.

This is a level 3 severe fault requiring immediate repair.

The B1751-00 fault code on the Seal U indicates a high-severity SRS fault: a short to body ground in the right rear seat side airbag squib circuit. This can stop the airbag from deploying and may affect pretensioner operation. Common causes include damaged under-seat wiring from seat movement or an internal short in the airbag module. The vehicle should be inspected by an authorised dealer immediately. Typical repair cost data is available.
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Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Mechanical wear of the under-seat wiring harness: Frequent forward and backward movement or folding of the right rear seat causes prolonged friction between the seat frame and the wiring harness sleeve. This friction damages the insulation, allowing the wire to directly contact the metal body frame and create a short to ground (most common cause, accounting for approximately 60% of cases).
  • 2Airbag module internal short circuit: Airbag inflator internal bridge wire shorts to the housing. Airbag module aging, moisture ingress (water entering through an open window), or improper previous repairs typically cause this fault (approx. 25% of cases).
  • 3Connector corrosion or water ingress: Poor sealing at the wiring harness connector under the right rear seat (usually designated KJ10 or similar) allows water ingress after car washing or wading, causing a short circuit between terminals or to ground (approx. 10% of cases).
  • 4Improperly secured wiring harness: After accident repairs or interior trim removal/installation, failing to correctly secure the wiring harness in the clips allows the seat slide rail to pinch or chafe the harness, causing a short to ground.
  • 5Internal SRS ECU fault: Damaged ECU internal detection circuit or driver chip triggers a false short circuit fault (very rare; confirm only after eliminating other possible causes).
What To Do
  • 1
    Safety preparation: Turn the vehicle power mode to OFF, disconnect the negative battery cable, and wait at least 90 seconds to fully discharge the SRS backup power supply and prevent accidental airbag deployment during repair.
  • 2
    Fault confirmation: Connect a genuine BYD diagnostic tool (such as VDS or ED400). Read the fault codes to confirm B1751-00 is present. Record the freeze frame data (ambient temperature and voltage). Clear the fault code, power on again, and observe if the code reappears.
  • 3
    Visual inspection: Remove the right rear seat (typically requires loosening the seat retaining bolts and sliding the seat backward). Inspect the yellow SRS wiring harness and connector (KJ10) under the seat for obvious wear, damaged insulation, signs of water ingress, or an unlocked connector.
  • 4
    Circuit isolation test: Disconnect the right rear seat side airbag connector. Use a multimeter to measure the resistance between the harness-side terminals (B/Y black/yellow wire and Y/L yellow/green wire) and body ground. Normal resistance is greater than 1 MΩ (infinite). If the resistance is too low, the harness is shorted to ground.
  • 5
    Voltage check: Keep the connector disconnected, switch the power mode to ON, and measure the voltage between the wiring harness side terminal and ground. Normal voltage is less than 1V. Any voltage present indicates a possible internal ECU fault or a short circuit to another power wire.
  • 6
    Airbag module test: If wiring harness measurements are normal, connect a dedicated 2.0-3.0Ω resistor (or a known-good airbag simulator) across the wiring harness connector and restore power. If the fault code clears and the SRS warning lamp turns off, this indicates an internal short circuit in the airbag module. Replace the airbag module.
  • 7
    Fault Repair: If the wiring harness is damaged, wrap the damaged area with insulating tape, install corrugated conduit for protection, and re-secure the harness away from the seat slide rail. If the connector has water ingress, clean it with electronic cleaner, blow it dry, and replace the connector if necessary. If the airbag module is faulty, replace it with an OEM airbag module (verify part number match).
  • 8
    System reset: After completing the repair, reconnect and lock all connectors, install the seat, and connect the battery. Use a diagnostic tool to clear the fault code and perform the SRS system self-check (typically, power on the vehicle, wait 10-20 seconds, and verify the SRS warning light turns off). Finally, perform a road test to verify the repair.
Real-World Cases
BYD DTC AI Analysis

Wiring harness chafing caused a short to ground.

✓
Symptoms: BYD Qin EV450 SRS warning light stays on. Scan tool reads DTC B1751-00. Diagnosis: Removed the right rear seat. Found the wiring harness protective sleeve beneath the seat rail damaged. Yellow-green wire insulation worn through, contacting the seat frame and causing a short to earth. Measured resistance to earth: 0.3Ω. Resolution: Taped the damaged section with electrical insulating tape. Fitted flame-retardant corrugated tubing. Rerouted the harness and secured it with cable ties to the seat base mounting slots, keeping clear of moving parts. Cleared the DTC. SRS light went out and function restored.
Original source ↗
BYD DTC AI Analysis

Internal short circuit in the airbag module

✓
Symptoms: After the vehicle drove through water (water entered because the right rear window was not fully closed), the SRS warning light illuminated, showing DTC B1751-00. Diagnosis: Disconnected the rear seat airbag connector and measured harness resistance to earth at >10MΩ (normal) and voltage to earth at 0V (normal), ruling out a harness fault. Bridged the circuit with a 2.5Ω resistor and the fault disappeared. Fitted the faulty airbag module to a known-good vehicle and the fault recurred, confirming an internal igniter short to earth within the airbag module. Resolution: Replaced the right rear side airbag module (part number must match the VIN). After fitting, performed system configuration and self-test. Fault resolved.
Original source ↗
BYD DTC AI Analysis

Poor connector contact causing intermittent short circuit.

✓
Symptoms: SRS warning light illuminates intermittently, mainly on rough roads. Scan tool detected intermittent fault code B1751-00. Diagnosis: Inspection of the connector under the right rear seat found the locking tab not fully engaged, the connector loose, and minor oxidation on the internal terminals. On bumpy roads, vibration caused the terminals to contact the body, producing a momentary short circuit. Resolution: Cleaned the connector terminals with electrical contact cleaner and applied a small amount of conductive grease. Reconnected the connector firmly and made sure the locking tab engaged fully. Secured the connector with cable ties to prevent loosening. Completed a 20 km road test with no fault recurrence.
Original source ↗
Other Seal U Fault Codes
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.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.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.B173712DTC B173712 indicates a short to power in the firing circuit of the right second-row side airbag module in the Supplemental Restraint System (SRS). Specifically, the "right second-row side airbag" typically refers to the side impact airbag located in the right B-pillar or the side of the right seat. The "12" suffix indicates a circuit short to battery positive (B+). This fault causes the following conditions: 1) The airbag may fail to ignite and deploy during a collision, resulting in a loss of side impact protection. 2) In extreme cases, unintended triggering may cause accidental airbag deployment. 3) The SRS control unit detects abnormally high circuit voltage (typically above 4.5V) and enters fault protection mode. This may disable the entire airbag system and continuously illuminate the instrument cluster airbag warning light.
Common problems reported for Seal U →Seal U 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.