AU
B16E0

DTC B16E0 indicates a short to ground in the Left Rear Impact Sensor signal circuit within the airbag system (SRS) — Atto 3

Safety System

DTC B16E0 indicates a short to ground in the Left Rear Impact Sensor signal circuit within the airbag system (SRS).

This sensor typically mounts in the left rear C-pillar, the left side of the rear bumper, or the inside of the left rear fender to monitor left rear collision acceleration.

A "short to ground" means the insulation resistance between the sensor signal line and body ground (GND) falls below the standard value (typically <1Ω).

This causes the SRS control unit (ACU) to detect a continuous low-voltage signal (approaching 0V), preventing it from acquiring normal acceleration change signals.

This fault forces the SRS into fail-safe mode, disabling the deployment function of the left rear side airbags (side curtain or rear seat airbags).

In extreme cases, this condition causes unintended airbag deployment or failure to deploy during a collision, posing a severe safety hazard.

4
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Harness abrasion and insulation damage: Long-term vibration, friction, or compression damages the sensor wiring harness insulation inside the left rear sill trim, C-pillar, or rear bumper, allowing the copper core to contact the vehicle body metal and cause a short to ground.
  • 2Sensor internal short circuit: Moisture ingress, aging, or impact damage to the crash sensor's internal piezoelectric element or circuit board causes a short circuit between the signal terminal and the housing (ground).
  • 3Connector water ingress and corrosion: Poor sealing of the rear bumper sensor connector allows water to enter during car washing, wading, or in damp environments, causing electrolytic corrosion between the pins and creating a path to ground.
  • 4Improper repair procedures: During rear bumper painting, sheet metal repairs, or installing parking sensors/reversing cameras, fixing screws pierce the wiring harness, or failing to secure the wiring harness correctly causes crushing and a short circuit.
  • 5Rodent or foreign object damage: During long-term outdoor parking, rodents chew the wiring harness, or foreign objects enter the rear bumper and chafe the wiring harness insulation.
What To Do
  • 1
    Safety preparation: Disconnect the 12V battery negative terminal and wait at least 3 minutes to fully discharge the SRS capacitor and prevent accidental airbag deployment during repair. Wear an anti-static wrist strap. Do not use radio equipment near the sensor.
  • 2
    Locate the sensor: Refer to the vehicle repair manual, remove the left rear C-pillar trim panel or rear bumper left cover panel, and locate the left rear impact sensor (usually a black or yellow connector with a locking clip).
  • 3
    Visual inspection: Check the sensor housing for cracks or deformation, the connector for looseness or signs of water ingress (green corrosion or white powder on the pins), and the wiring harness for wear, cuts, or scorch marks where it passes through sheet metal holes.
  • 4
    Circuit measurement: Set the multimeter to the resistance range, disconnect the sensor connector, and measure the resistance between the signal wire (usually yellow or pink) and body ground. The normal reading is infinity (OL). A reading <5 Ω confirms a short to ground. Measure the sensor component resistance. The normal range is 2-5 kΩ (refer to the specific vehicle standard). A reading close to 0 Ω indicates an internal sensor short circuit.
  • 5
    Wiring harness section inspection: If the sensor is normal, peel back the harness corrugated conduit section by section from the connector toward the ACU. Inspect the harness routed near the door sill and seat rails for damage. Monitor the signal wire voltage using an oscilloscope. The normal bias voltage is approximately 2.5V. If the voltage remains at 0V, locate the short circuit.
  • 6
    Repair and Verification: Repair the damaged wiring harness (solder and apply heat-shrink tubing for double insulation, then wrap with PVC tape), or replace the faulty sensor. Reconnect the connector, reconnect the negative terminal, use the diagnostic tool to clear the fault code, and perform a 'sensor dynamic test' (lightly tap the sheet metal near the sensor and observe data stream changes). Verify DTC B16E0 does not return and the SRS warning light turns off.
Real-World Cases
BYD DTC AI Analysis

Left rear impact sensor shorted after wading through water in Song MAX.

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Vehicle: 2019 Song MAX DM, 32,000 km. Symptom: Dashboard SRS warning light permanently illuminated. Scan tool retrieved DTC B16E0. History: Vehicle waded through water to half wheel-hub depth one week prior. Investigation revealed significant water ingress in the sensor connector on the inner side of the left rear bumper, with pins oxidised and blackened. Disassembly found the connector seal had aged, causing poor sealing. Repair: Cleaned connector pins using electrical contact cleaner and lint-free cloth. Replaced sensor (internal moisture damage). Applied dielectric grease to the connector and wrapped with waterproof tape. Fault resolved.
BYD DTC AI Analysis

Yuan EV wiring harness pinched and shorted after accident repair

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2019 Yuan EV535. Repaired at a workshop after a minor left-rear collision. After repair, SRS warning light on, DTC B16E0 stored. Diagnosis: Impact sensor in correct position and tested normal, but signal wire to ground measured 0.3 Ω. Investigation found the workshop had not secured the wiring harness in its retaining clip when refitting the rear bumper. A mounting screw pinched the harness and damaged the insulation. Repair: Cut out the damaged harness section, soldered in an extension wire, insulated with double-layer heat-shrink tubing, then rerouted and secured the harness to specification. Fault cleared.
BYD DTC AI Analysis

Tang DM left rear C-pillar wiring harness chafed, intermittent short circuit

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Model: 2021 Tang DM. Intermittent SRS warning light; DTC B16E0 appears intermittently. Diagnosis: Initial circuit measurements normal, but wiggling the harness caused a sudden resistance change. Removed and inspected the left rear C-pillar trim panel. Found the sensor harness rubber grommet had dislodged where it passes through the sheet metal hole. Long-term chafing against the sharp metal edge had exposed the copper conductors. Repair: Repaired the damaged harness section, reinstalled the rubber grommet (secured with sealant), and added corrugated tubing at the chafing point for protection. Multiple road tests — fault did not recur.
BYD DTC AI Analysis

Qin Pro sensor internal circuit breakdown

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Model: 2020 Qin Pro (petrol). No collision history; SRS light suddenly came on. Diagnosis: Measured signal wire voltage at the sensor connector to earth: 0V (normal: 2.5V). Disconnected the sensor, measured harness resistance to earth: infinite (normal). However, the sensor’s signal terminal had continuity to its housing. Disassembled the sensor and found burn marks on the internal PCB. Root cause: internal zener diode breakdown shorted to earth. Repair: Replaced with OEM left rear impact sensor (P/N ...), performed SRS configuration coding and matching. Fault resolved.
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.