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B16E0

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

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.

The B16E0 fault code on the Qin Plus indicates a high-severity short to ground in the left rear impact sensor signal circuit for the airbag system. This can stop the SRS from reading crash data correctly and may disable left rear airbag deployment. Common causes include damaged or chafed wiring near the rear sill/C-pillar or an internally shorted impact sensor. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Qin Plus
  • 1Chafed wiring harness: Long-term vibration, friction, or pinching damages the sensor wiring harness insulation inside the left rear sill trim, C-pillar, or rear bumper. The exposed copper core contacts the vehicle body metal, causing a short to ground.
  • 2Internal sensor short circuit: Moisture, 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: A poorly sealed rear bumper sensor connector allows water entry during car washes, wading, or in humid conditions, causing electrolytic corrosion between the pins and creating a path to ground.
  • 4Improper repairs: During rear bumper painting, sheet metal repair, or parking sensor/reversing camera installation, mounting screws pierce the wiring harness, or an improperly secured wiring harness causes crush damage and a short circuit.
  • 5Rodent or foreign object damage: During prolonged outdoor parking, rodents chew the wiring harness, or foreign objects enter the rear bumper and wear through the wiring harness insulation.
What To Do
  • 1
    Safety Preparation: Disconnect the 12V battery negative terminal and wait at least 3 minutes for the SRS capacitor to fully discharge to 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 to remove the left rear C-pillar trim panel or left rear bumper cover, and locate the left rear impact sensor (usually equipped with a black or yellow connector and a locking clip).
  • 3
    Visual inspection: Check the sensor housing for cracks or deformation, the connector for looseness or signs of water ingress (green pins or white powder), and the wiring harness for wear, cuts, or scorch marks where it passes through sheet metal holes.
  • 4
    Circuit measurement: Disconnect the sensor connector. Set a multimeter to the resistance setting and measure the resistance between the signal wire (usually yellow or pink) and body ground. The normal reading is infinite (OL). A reading <5 Ω confirms a short to ground. Measure the sensor body resistance. The normal range is 2-5 kΩ (refer to the specific vehicle standard). A reading near 0 Ω indicates an internal sensor short circuit.
  • 5
    Sectional harness inspection: If the sensor is normal, peel back the harness corrugated conduit section by section from the connector toward the ACU. Inspect the harness closely near the door sill and seat rails to locate damage. Use an oscilloscope to monitor the signal wire voltage. 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 and the battery negative terminal. Use a diagnostic tool to clear the fault code. 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 Qin Plus 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.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.B110BDTC B110B indicates a fault in the internal air pump (sampling pump) of the PM2.5 air quality detector. This pump draws cabin or outside air into the PM2.5 sensor detection chamber, enabling the laser scattering sensor to measure real-time particulate matter concentration. The air conditioning controller (or BCM) sets this DTC upon detecting an open or short circuit in the pump drive circuit, or abnormal current caused by a seized pump motor. This fault disables the "Green Clean" system, causes the instrument cluster air quality display to read abnormally or disappear, and disables the automatic fresh air/recirculation switching function. It does not affect the vehicle powertrain or core thermal management functions.B173A1ADTC B173A1A indicates the right middle-row side airbag (typically located on the side of the right second-row seat or inside the C-pillar trim panel) igniter circuit resistance measures 0 Ω. In the Supplemental Restraint System (SRS), normal airbag igniter resistance ranges between 2.0 and 5.0 Ω. A resistance of 0 Ω indicates a short to ground or a short between circuit wires, preventing the Airbag Control Unit (ACU) from establishing a normal monitoring circuit. This safety-critical fault prevents the airbag from deploying during a collision, continuously illuminates the instrument panel SRS warning lamp, and may force the entire airbag system into fail-safe mode.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Qin Plus →Qin Plus overview →
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.