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B1792-00

This fault code indicates the driver-side second stage seat belt pretensioner ignition circuit resistance falls below the normal threshold set by the SRS control unit (ACU) (typically 2 — Atto 3

Safety System

This fault code indicates the driver-side second stage seat belt pretensioner ignition circuit resistance falls below the normal threshold set by the SRS control unit (ACU) (typically 2.0-4.0Ω; actual detected value below 1.5Ω or close to 0Ω).

The second stage pretensioner is part of the dual-stage gas generator system, providing progressive restraint force during a severe collision.

Low resistance typically indicates an internal squib short circuit, a wiring harness short to ground, or internal connector bridging.

This fault causes the ACU to disable the pretensioner function.

In extreme cases, the pretensioner may fail to deploy during a collision, or false fault detection during driving may continuously illuminate the SRS warning light, compromising the overall occupant restraint system protection strategy.

4
Cases Logged
Real-World Cases
BYD DTC AI Analysis

Qin EV300 pretensioner shorted after driving through water

✓
A 2017 BYD Qin EV300 came in with the SRS warning light on after driving through flood water. Retrieved DTC B1792-00. Found water in the wiring harness connector beneath the driver's seat; resistance between the pretensioner terminals measured 0.8Ω. Disassembly revealed the connector seal had deteriorated, allowing water ingress that caused a micro-short between the terminals. Repair: Replaced the seat belt retractor assembly (pretensioner had shorted and failed), fitted a new waterproof connector with insulation treatment, and cleared the drainage holes beneath the seat. Fault cleared.
BYD DTC AI Analysis

Seat modification damaged the wiring harness

✓
One week after installing racing seats in their 2018 BYD Qin EV450, the owner saw DTC B1792-00. The technician found the pretensioner harness unsecured during the modification. The seat rail bracket had pinched the harness repeatedly, wearing through the insulation and shorting the core wire to ground. Repair: Cut out the damaged section, soldered the joint and insulated it with heat-shrink tubing. Re-secured the harness along the standard routing path with adequate clearance from moving parts. Cleared the code; operation normal.
BYD DTC AI Analysis

Pretensioner internal resistance drift due to ageing

✓
2017 Qin 100, 120,000 km. Intermittent DTC B1792-00: present when cold, clearing when hot. Pretensioner resistance dropped to 1.2Ω in cold conditions, returning to 2.5Ω when warm. Diagnosis: Moisture ingress and aging of the internal igniter propellant caused abnormal temperature coefficient. Fix: Replaced OEM driver's side seat belt retractor assembly. Fault eliminated. Note: Verify soft faults with multiple measurements across different temperature environments.
BYD DTC AI Analysis

Connector pin backed out causing short circuit

✓
Following accident repairs, the vehicle set DTC B1792-00. Inspection found the B-pillar pretensioner connector had been misaligned during reinstallation, causing one terminal to back out and bend, contacting the adjacent terminal and creating a short circuit. Repaired the pin, reinstalled it using a dedicated terminal removal tool, applied conductive paste to ensure good contact, and relocked the connector. Fault cleared.
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: Community This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.