AU
B1632-00

B1632-00 indicates a short circuit to vehicle power (B+) in the front passenger (right) side airbag ignition circuit — Atto 3

Safety System

B1632-00 indicates a short circuit to vehicle power (B+) in the front passenger (right) side airbag ignition circuit.

In the BYD SRS (Supplemental Restraint System) architecture, this fault specifically refers to abnormal continuity between the inflator circuit of the front passenger seat side airbag or the right curtain airbag and 12V constant power or ignition power.

This fault is a hard short.

The SRS control unit (ACU) detects the ignition circuit voltage continuously exceeding the threshold (typically >5V).

To prevent unexpected deployment, the system immediately cuts off the affected airbag ignition circuit and illuminates the airbag fault warning lamp (SRS MIL).

This fault presents an extremely high safety risk: the short circuit may cause unexpected airbag deployment resulting in personal injury.

Additionally, the fault prevents normal airbag deployment, disabling collision protection.

5
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Wiring harness wear under the front passenger seat: Frequent fore-and-aft seat adjustment causes the side airbag wiring harness (usually integrated into the seat harness) to rub against the seat track and slide rail bracket. This damages the insulation, allowing the wire to contact live parts of the metal frame.
  • 2Right front door hinge wiring harness crushed: The side curtain airbag is located above the door or in the B-pillar. Frequent door opening and closing crushes and chafes the door-to-body wiring harness, causing power wires (such as door lock or window regulator power supplies) to short circuit with the airbag ignition wire.
  • 3Airbag igniter internal short circuit: The igniter resistance wire inside the front passenger airbag module short-circuits to the housing or power terminal. Manufacturing defects, airbag aging, or previous physical impact typically cause this.
  • 4Water ingress or liquid contamination: Water entering the front passenger seat or carpet (A/C condensate, sunroof leak, spilled drinks) causing a short circuit or conductive corrosion between the airbag connector terminals (usually located under the seat or at the base of the B-pillar).
  • 5Improper modification or repair: fixing pins piercing the wiring harness during the installation of seat covers, seat heating pads, or floor sound insulation; or improperly securing the wiring harness after accident repairs, allowing seat rails or door panel clips to pinch the harness and damage the insulation.
What To Do
  • 1
    Safety isolation: Disconnect the 12V battery negative terminal. Wait at least 90 seconds to fully discharge the SRS energy storage capacitor. Hang an 'Airbag Under Repair' warning sign. Do not reconnect power during the repair.
  • 2
    Fault Confirmation and Freeze Frame Analysis: Connect the VDS2000 or Launch X431 diagnostic tool and read the freeze frame data for DTC B1632-00. Confirm the vehicle speed, temperature, and voltage conditions at the time of the fault to determine whether it is an intermittent fault.
  • 3
    Visual and physical inspection: Check the front passenger seat, right front door trim panel, and B-pillar trim for signs of removal; check under the seat, door hinges, and floor harness pass-through points for wiring harness wear, pinching, water damage, or burn marks; focus on the dedicated yellow SRS wiring harness (typically double-insulated).
  • 4
    Circuit isolation test: Remove the SRS control unit (ACU) and disconnect the front passenger airbag connector (usually located on the floor harness or under the seat). Use a multimeter to check the airbag-side wiring harness for a short to power. Measure the resistance between the ignition wire (usually yellow/black) and B+; normal resistance is infinite. Measure the inflator resistance (via the airbag connector); normal resistance is 2.0-3.0 Ω.
  • 5
    Harness continuity and insulation check: If the harness has a short circuit, use a probe to measure continuity section by section from the ACU connector to the airbag connector. Focus on the areas beneath the seat rail and the door hinge bend. If damaged, repair the wire with solder, apply double insulation with heat-shrink tubing, install abrasion-resistant corrugated conduit and fabric tape, and adjust the harness routing to avoid interference with moving parts.
  • 6
    Airbag module inspection: If the wiring harness is normal, directly measure the resistance between the airbag module igniter terminals and the insulation to the housing. If an internal short circuit exists, replace the front passenger airbag assembly (never repair the airbag module). Record the serial numbers of the old and new modules during replacement.
  • 7
    SRS system reset: After repair, reconnect all connectors (ensure an audible click), connect the battery, and clear the fault code. Use the diagnostic tool to perform the 'SRS Configuration' or 'Coding' function (some models require reconfiguring airbag parameters after replacing components), then perform 'System Self-learning'.
  • 8
    Function verification: Perform a static test: read the data stream and confirm the front passenger airbag resistance is within the normal range (2.3±0.3Ω) and the voltage is 0V. Perform a dynamic simulation (use an airbag test tool to simulate the load; never measure the igniter directly) and confirm the system generates no fault codes.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

Qin EV450 passenger seat wiring harness chafing caused airbag short circuit

✓
Symptoms: The SRS light on the dash stayed on. Pulled fault code B1632-00 (passenger side airbag short to power). Freeze frame data showed the fault triggered after adjusting the seat. Diagnosis: Removed the passenger seat. The under-seat wiring harness had worn through on the sharp edge of the slide rail when the seat was at its front-most position. The yellow airbag wire (IGN+) and the seat heating power wire (12V constant) were making contact with their conductors exposed. Measured 12V on the airbag wire to ground. Fix: Repaired the damaged harness – cut out the damaged section, soldered in an extension, and insulated with heat shrink tubing. Installed a rubber grommet along the rail edge. Adjusted the harness attachment point to add slack. Cleared the fault code; airbag circuit resistance returned to 2.4 Ω.
BYD DTC AI AnalysisFrom Chinese market (translated)

Qin Pro DM right front door hinge wiring harness pinched short

✓
Symptoms: Following an accident repair (RH front door replacement), the instrument cluster displayed an airbag fault. The diagnostic scanner reported DTC B1632-00. Diagnosis: Inspection of the wiring harness at the door hinge revealed the previous repair had not secured it correctly. The hinge was pinching the harness when closing the door, damaging the insulation of the curtain airbag igniter wire (yellow/green) and door lock power wire (red/white) and causing a short circuit. Solution: Replaced the RH front door wiring harness assembly (the damage was too concentrated to repair). Re-routed the harness according to the standard layout and secured it using the dedicated retaining clips, ensuring the wiring does not interfere with the hinge in either the fully open or fully closed position. Fault rectified.
BYD DTC AI AnalysisFrom Chinese market (translated)

Front passenger airbag connector corroded and shorted after the Qin 100 waded through water.

✓
Symptoms: After a heavy rainstorm, the vehicle drove through floodwater (water submerged the floor), the SRS warning light came on and DTC B1632-00 was stored. Diagnosis: Found water pooling under the front passenger seat. The SRS wiring harness connector (2-pin yellow plug) had internal water ingress, with copper oxide buildup between terminals causing a short circuit between positive and negative (measured resistance: 0.8Ω). Resolution: Completely removed the standing water, cleaned the connector terminals with electronic contact cleaner, blow-dried them, and applied conductive protectant. Replaced the airbag harness connector due to severe corrosion, then re-waterproofed the connection by wrapping with waterproof tape and fitting a waterproof boot. Cleared the fault code.
BYD DTC AI AnalysisFrom Chinese market (translated)

Qin EV300 Airbag Module Internal Fault Replacement Case

✓
Symptoms: No collision history. SRS warning lamp illuminated suddenly while driving. DTC B1632-00 could not be cleared. Diagnosis: Disconnected the passenger-side airbag connector. Measured harness side for short to power — none found. Measured directly at the airbag module igniter terminals and found continuity to the airbag housing (short to ground), confirming internal insulation failure of the igniter. Solution: Replaced the passenger seat side airbag assembly (part no. ...). Used new fixing bolts tightened to standard torque (typically 8–10 Nm). Ensured correct airbag orientation (label facing outward). Performed new module configuration via diagnostic tool. Fault resolved.
BYD DTC AI AnalysisFrom Chinese market (translated)

Modified seat covers on a Qin 80 pierced the wiring harness, causing a short circuit.

✓
Symptoms: One week after fitting leather seat covers, the dashboard displayed an airbag fault warning. Read DTC B1632-00. Diagnosis: Inspected the passenger seat and found the metal retaining clips used to secure the seat covers were too long. They had pierced the seat side and penetrated the SRS wiring harness, puncturing the airbag igniter wire. The damaged wire contacted both the metal clip (body earth) and adjacent power supply wires simultaneously, creating a short to power. Resolution: Removed the non-compliant modification clips. Repaired the damaged wiring (as the damage was scattered, replaced the entire seat harness after local repairs). Refitted the seat covers with dedicated plastic clips, keeping them clear of the airbag harness routing. Cleared the fault codes.
Other Atto 3 Fault Codes
P0A0DBattery Energy Control Module Requested MIL IlluminationP0AA6Hybrid Battery Voltage System Isolation FaultP1A00Drive Motor "A" Performance — BYD proprietaryB1108For 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.
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. Sources: [1]