AU
B170E11

B170E11 indicates a short to ground in the ignition circuit of the right side curtain airbag — Atto 8

Safety System

B170E11 indicates a short to ground in the ignition circuit of the right side curtain airbag.

In the BYD SRS (Supplemental Restraint System) architecture, this fault code indicates the airbag control unit (ACU) detects an abnormally low-resistance path between the right side curtain airbag squib wiring and vehicle body ground (typically below the 1.5-2.0 ohm threshold).

This short circuit causes the ACU to determine the curtain airbag cannot deploy normally, triggering fail-safe mode.

The instrument panel airbag warning light illuminates continuously, and the system suspends deployment control for this curtain airbag.

Consequently, the right side curtain airbag may fail to activate during a side collision, severely compromising crash protection for right-side occupants, particularly head protection.

Potential causes include damaged wiring harness insulation, connector water ingress and corrosion, an internal short circuit in the clock spring, or a squib failure within the curtain airbag module itself.

3
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Right curtain airbag wiring harness wear: Loose wiring harness retaining clips inside the A-pillar, B-pillar, or C-pillar trim panels cause the harness to rub against sharp metal body edges over time, damaging the insulation and shorting the wire to ground.
  • 2Connector water ingress and corrosion: A degraded sealing ring on the right curtain airbag connector (usually located above the B-pillar or roof side rail) allows water intrusion during heavy rain, car washes, or leaks from a blocked sunroof drain tube. This corrodes the internal terminals and causes a short to ground.
  • 3Clock spring or spiral cable fault: If the right curtain airbag circuit on this model routes through the B-pillar wiring harness spiral cable (clock spring), a broken internal flat cable or abnormal winding may short the wire core to ground.
  • 4Curtain airbag module internal fault: The curtain airbag assembly squib internally shorted to ground due to manufacturing defects, aging, or previous impact.
  • 5SRS ECU monitoring circuit false detection: In very rare cases, a fault in the airbag control unit internal monitoring circuit triggers a false short circuit fault.
What To Do
  • 1
    Safety Preparation and Power Isolation: For new energy vehicles, first disconnect the high-voltage service disconnect. For all models, disconnect the 12V battery negative terminal and wait at least 90 seconds (3 minutes for some models) to allow the SRS capacitor to fully discharge and prevent accidental airbag deployment.
  • 2
    Visual and physical inspection: Remove the right A-pillar and B-pillar upper trim panels and the roof side trim panel. Check the curtain airbag wiring harness for obvious wear, pinching, damage, or signs of water ingress. Focus on the contact points between the wiring harness and the vehicle body metal.
  • 3
    Resistance measurement and fault location: Use a multimeter (do not use the continuity buzzer setting on the airbag circuit) to measure the resistance to ground of the right curtain airbag circuit at the SRS ECU connector. If the resistance is close to 0 ohms, disconnect the intermediate connectors section by section and measure each section to determine if the short circuit is in the ECU-to-connector section, the connector-to-curtain airbag section, or inside the curtain airbag module.
  • 4
    Connector handling: If the connector has water ingress, thoroughly clean the terminals with electrical contact cleaner, blow dry with compressed air, apply special conductive grease, replace the waterproof sealing ring, and ensure a secure connection.
  • 5
    Harness repair or replacement: For a damaged harness, cut out the damaged section and solder or crimp high-temperature wire of the same specification (usually yellow wire). Apply double-layer insulation (heat shrink tubing + electrical tape) and re-secure the harness routing to prevent interference.
  • 6
    Component replacement verification: If the curtain airbag module has an internal short circuit, replace the right curtain airbag assembly with a genuine part. (Note: Handle airbag components with care, avoid dropping them, and verify correct polarity during installation.)
  • 7
    System reset and road test: Reconnect all components and power supply. Use VDS2000/VDS1000 to clear the fault code. Perform the SRS system self-check (Active Test or self-check procedure). Confirm B170E11 does not return and the instrument cluster airbag warning light turns off.
Real-World Cases
BYD DTC AI Analysis

Qin Pro: Right curtain airbag wiring harness chafed at A-pillar, short circuit

✓
The airbag warning light on the instrument panel illuminated intermittently. VDS diagnostics retrieved fault code B170E11 (right curtain airbag short to earth). Removed the right A-pillar trim and found the curtain airbag harness retaining clip had come loose. The harness had been rubbing against the A-pillar metal frame edge during driving, wearing through the insulation and allowing the copper core to short directly to earth. Repair: Re-wrapped the damaged harness with high-temperature insulation tape and corrugated tubing, rerouted it to avoid sharp edges, and reinstalled the retaining clips, ensuring clearance exceeded 15 mm. Cleared the fault codes and monitored for one month with no recurrence.
Original source ↗
BYD DTC AI Analysis

E2 Right side curtain airbag connector water ingress corrosion

✓
After a heavy rainstorm, the airbag warning light stayed on constantly. A VDS scan showed DTC B170E11. Inspected the right B-pillar upper curtain airbag connector (white 2-pin) and found clear water stains and green copper corrosion inside, with abnormally low resistance across the terminals. Traced the leak to a detached right rear sunroof drain hose joint, allowing rainwater to seep into the B-pillar. Repair: Cleaned the connector terminal oxides with dedicated electronic contact cleaner. Applied conductive anti-corrosion paste. Replaced the connector seal. Repaired the sunroof drain hose. Performed a water spray test, confirmed no leakage, then reassembled. Fault resolved.
Original source ↗
BYD DTC AI Analysis

Qin EV curtain airbag module internal short circuit after collision repair

✓
After a side-impact collision, an authorised service centre replaced the right curtain airbag and SRS ECU. After delivery, the instrument cluster still displayed an airbag fault. VDS read DTC B170E11. Inspected the wiring harness – no abnormality. Measured resistance of the newly replaced right curtain airbag module and found continuity between both igniter terminals and the housing (ground) – internal short circuit confirmed (likely damaged during transport or storage). Solution: Replaced with another genuine right curtain airbag module. Performed coding and system calibration using VDS. Ran a crash sensor simulation test. Confirmed right curtain circuit resistance within normal range (2.0–3.0 ohms). Cleared DTC; system self-test passed.
Other Atto 8 Fault Codes
B1108For 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.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.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.
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.