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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) — Seal 6 EV

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 Seal 6 EV indicates a short to ground in the left rear impact sensor signal circuit for the airbag system. This is a high severity safety issue because it can disable left rear side airbag deployment, or rarely cause unintended deployment. Common causes include damaged wiring insulation or an internal sensor short from moisture or impact. 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 — Seal 6 EV
  • 1Wiring harness chafing and damaged insulation: Long-term vibration, friction, or compression 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.
  • 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 entry during car washing, wading, or in damp conditions, causing electrolytic corrosion between the pins and creating a path to ground.
  • 4Improper repair procedures: During rear bumper painting, sheet metal repair, or parking sensor/reversing camera installation, fixing screws pierce the wiring harness, or an incorrectly secured wiring harness causes crushing 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 the 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. Remove the left rear C-pillar trim panel or the left rear bumper cover to 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 body panel holes.
  • 4
    Circuit measurement: Set the multimeter to the resistance setting. Disconnect the sensor connector and measure the resistance between the signal wire (usually yellow or pink) and body ground. The normal reading is infinite (OL). A reading <5Ω confirms a short to ground. Measure the resistance of the sensor itself. The normal range is 2-5kΩ (refer to the specific vehicle standard). A reading near 0Ω 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. Carefully inspect the harness passing near the door sill and seat rails for damage. Monitor the signal wire voltage using an oscilloscope. Normal bias voltage is approximately 2.5V. If the voltage remains at 0V, pinpoint the short circuit location.
  • 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 negative battery terminal. Use the diagnostic tool to clear the fault code. Perform the 'sensor dynamic test' (lightly tap the sheet metal near the sensor and observe data stream changes). Confirm DTC B16E0 does not return and the SRS warning lamp 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 Seal 6 EV 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.B1737DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive). The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω). If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power. This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current. In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.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 Seal 6 EV →Seal 6 EV 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.