AU
B1667-00

DTC B1667-00 indicates the airbag control unit (SRS ECU) detects a short to body ground in the signal circuit of the left side impact sensor (typically installed inside the left B-pillar reinforcement panel) — Atto 3

Safety System

DTC B1667-00 indicates the airbag control unit (SRS ECU) detects a short to body ground in the signal circuit of the left side impact sensor (typically installed inside the left B-pillar reinforcement panel).

This sensor is typically a MEMS capacitive or piezoelectric accelerometer.

During normal operation, it returns a bias resistance of approximately 2.1-2.9 kΩ and a signal voltage of approximately 2.5 V to the ECU.

When wiring harness insulation breaks, water enters the connector, or the sensor shorts internally, the ECU detects a continuous voltage signal below 0.5 V (short-to-ground threshold) and triggers this DTC.

This fault disables the trigger threshold determination for the left side airbag and curtain airbag.

During a side collision, the airbags may fail to deploy promptly, or signal interference during normal driving may cause unintended deployment.

This is a highest-level safety fault.

4
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Sensor wiring harness insulation damage causing a short to ground: commonly caused by underbody scraping, loose harness retaining clips causing the harness to rub against metal body edges, or harness crush damage during sill trim panel removal and installation.
  • 2Connector water ingress and corrosion: Poor sealing in the left B-pillar area, a blocked and leaking sunroof drain hose, or directly spraying the B-pillar with a high-pressure washer causes connector terminal oxidation, resulting in a short to ground.
  • 3Internal damage to the sensor body: Severe vibration (such as improper removal and installation, or accidents) causes internal piezoelectric element or circuit board breakdown, or electronic components fail due to aging after the sensor exceeds its 5-year service life.
  • 4Installation defects: deformed sensor mounting bracket (not straightened after accident repair), excessive tightening torque cracking the housing, or a missing mounting spacer causing the sensor housing to directly contact the vehicle body metal and create a short circuit.
  • 5SRS ECU internal fault: A damaged internal ECU sampling circuit causes a false short-to-ground fault. Rule out by substitution (occurrence rate: approx. 5-10%).
What To Do
  • 1
    Safety preparation: Wear insulated gloves, disconnect the 12V low-voltage battery negative terminal, and wait at least 90 seconds to fully discharge the SRS system capacitors (confirm the READY light is off for the new energy vehicle high-voltage system).
  • 2
    Fault confirmation: Use a BYD dedicated diagnostic tool (VDS or ED400) to read SRS system fault codes, confirm B1667-00 is the current fault code, and record freeze frame data (ambient temperature, voltage value).
  • 3
    Physical inspection: Remove the left B-pillar lower trim panel and sill trim panel. Visually inspect the wiring harness corrugated conduit for damage and check connector KG10 (or K05, depending on vehicle model) for signs of water ingress (green copper corrosion, white crystals).
  • 4
    Circuit isolation check: Disconnect the left side impact sensor connector. Use a multimeter to measure the resistance between the wiring harness side terminal (KG10-12 or corresponding pin) and body ground. Normal resistance is >1MΩ. If the resistance is <1Ω, this confirms a short to ground. Inspect the wiring along the circuit for damage.
  • 5
    Sensor body inspection: Measure the resistance between the sensor-side terminals. The normal value is 2.1-2.9 kΩ (refer to the specific vehicle repair manual). If the resistance is close to 0 Ω or infinite, replace the sensor.
  • 6
    Connector repair: If terminals are oxidized, clean with electrical contact cleaner and apply conductive grease. If the locking tab is damaged or a terminal has backed out, replace the entire connector assembly. Ensure the waterproof sealing ring is intact.
  • 7
    Wiring harness repair: Insulate the damaged wiring harness with double-layer heat-shrink tubing, adjust the harness routing to avoid contact with sharp metal edges, and re-secure the clips to ensure no stress.
  • 8
    Replace the sensor (if required): Use genuine parts (such as part number BYD-3636010 series). Verify the mounting surface is flat and undeformed. Tighten to the standard torque of 8 N·m (never use an impact wrench). Note the sensor installation direction mark (usually an 'UP' arrow pointing to the roof or 'F' pointing to the front of the vehicle).
  • 9
    System reset: Reconnect the battery, turn the power ON without starting the vehicle, and observe if the SRS warning light turns off after 6 seconds. Use a diagnostic tool to clear the fault code, and perform 'SRS System Self-Learning' or 'Crash Sensor Zero-Point Calibration' (required on some models).
  • 10
    Verification test: Perform a road test for at least 30 minutes, including bumpy roads. Use the diagnostic tool to read the data stream and confirm the left crash sensor signal voltage is within 2.3-2.7V with no fluctuation.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

Poor connector contact damaged the sensor on BYD Qin Pro DM

✓
The airbag warning light on the instrument panel stayed on. Read DTC B1667-00. Inspection revealed the vehicle had recently undergone left door sheet metal and paint repair. Removing the B-pillar trim during that work left the left side impact sensor connector not fully seated. Reconnecting it cleared the fault temporarily, but it returned the next day. Further measurement showed the sensor's internal resistance had abnormally dropped to 1.2 kΩ (standard 2.3 kΩ). We determined the loose connector caused an intermittent short circuit; long-term poor contact overheated and damaged the sensor's internal circuit. Replaced the left side impact sensor (part number: BYD-3636010), installing it on the B-pillar reinforcement plate at the specified torque of 8 N·m. Fault completely resolved.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Song Plus EV door sill wiring harness damaged, short to ground

✓
After turning the ignition on, the airbag warning light stayed on. The scan showed DTC B1667-00. The data stream showed the left collision sensor voltage signal was 0V (normal 2.5V). I disconnected the sensor connector inside the left B-pillar and measured terminal KG10-12 at the harness side. Resistance to ground was less than 1Ω, confirming a short to ground. I traced the harness and found a retaining clip had compressed the wiring inside the left sill trim, damaging the insulation and exposing the copper wire to the body. Repair: I re-wrapped the damaged harness with double-layer heat shrink tubing for insulation, rerouted the harness to avoid the clip, and cleared the fault codes. The SRS system returned to normal.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Han EV connector terminal pin backed out causing intermittent short circuit

✓
The airbag warning light came on intermittently and sometimes went out automatically. The scan tool retrieved historical DTC B1667-00 and current DTC B1666-00 (open circuit), indicating an intermittent fault. Inspection found minor damage to the left crash sensor connector latch. Wiggling the wiring harness caused resistance between terminals KG10-12 and K05(A)-2 to fluctuate between 0.5Ω and infinity. The backed-out terminal pin caused an intermittent short to ground. Replaced the left crash sensor harness connector assembly, ensured correct terminal spring tension, fully seated the connector, and locked the latch. Road-tested over rough surfaces; the fault did not reoccur.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

Incorrect sensor installation after accident repair on a BYD Destroyer 05

✓
After a left side collision, an outside repair shop replaced the left front door and B-pillar trim. Following the repair, the airbag warning light stayed on and DTC B1667-00 could not be cleared. Inspection found the left side impact sensor was the old unit removed during the accident. It had visible cracks but had not been replaced; resistance measured 0Ω (internal short). Further inspection revealed slight deformation at the B-pillar inner panel mounting point, causing the sensor installation angle to exceed 5° (workshop manual requires ±5°). The mounting bolt torque was excessive (measured 15 N·m, standard 8 N·m), which cracked the sensor housing. Solution: Straightened and repaired the B-pillar inner panel mounting surface. Replaced the sensor and installed it to standard torque and orientation. Fault resolved.
Original source ↗
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]