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B16EF

DTC B16EF indicates the SRS (Supplemental Restraint System) control module detects a communication interruption or missing physical connection with the Right Rear Impact Sensor — Qin Plus

Safety System

DTC B16EF indicates the SRS (Supplemental Restraint System) control module detects a communication interruption or missing physical connection with the Right Rear Impact Sensor.

This sensor typically mounts in the right C-pillar, rear door frame, or inside the right rear quarter panel to monitor collision acceleration changes on the right rear side of the vehicle.

During a side-rear collision, the sensor transmits the acceleration signal to the SRS module to determine whether to deploy the right curtain and side airbags.

A "not connected" fault means the SRS module cannot detect the sensor during initialization or periodic communication checks.

Causes include an open circuit, disconnected connector, internal sensor open circuit, or abnormal module power supply.

This fault disables the right rear collision protection function.

As a safety-critical fault, it requires immediate repair.

The B16EF fault code on the Qin Plus indicates the SRS module cannot communicate with, or detect, the right rear impact sensor. Severity is medium because it can disable right rear side or curtain airbag protection. Common causes include a loose sensor connector, poor terminal contact, or damaged wiring in the right rear sill/C-pillar area. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available from recorded cases.
3
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Sensor harness connector loose, terminal backed out, or poor contact: Commonly occurs due to incomplete connector seating after accident repairs, or long-term vibration loosening the retaining clip.
  • 2Wiring harness open or short circuit: The wiring harness in the right rear sill and C-pillar area breaks after water exposure, accidents, or long-term bending, or shorts to ground or power due to rodent damage or chafing against metal edges.
  • 3Internal sensor body fault: Damage to the internal piezoelectric element or processing circuit causes no signal output or a power supply short circuit.
  • 4SRS control module power supply or communication fault: Abnormal module IGN power supply or ground circuit, or CAN bus communication circuit fault, preventing sensor recognition.
  • 5Sensor installation/configuration error: Failed to write the configuration code (VIN matching or sensor position learning) after replacing the sensor, or installed a sensor with the incorrect part number.
What To Do
  • 1
    Safety Preparation and Fault Confirmation: Disconnect the negative battery terminal and wait at least 90 seconds to fully discharge the SRS capacitor. Use VDS2000 or a dedicated BYD diagnostic tool to read the fault codes. Confirm B16EF is a current fault (ACTIVE), not a history fault. Verify the 'Right Rear Impact Sensor Status' in the data stream displays 'Not Connected' or 'Communication Failure'.
  • 2
    Physical connection check: Remove the right C-pillar trim panel or rear door sill trim panel. Locate the right rear impact sensor (usually a yellow connector). Verify the connector is fully seated. Check for broken locking tabs, backed-out terminals, or corrosion. Inspect the sensor mounting bracket for deformation or looseness.
  • 3
    Wiring continuity and voltage measurement: Disconnect the sensor connector and SRS module connector. Measure the end-to-end harness continuity (should be less than 1Ω). Measure the power wire voltage to ground (should be 12V battery voltage). Measure the ground wire resistance to ground (should be less than 1Ω). Check the signal wire for a short to power or ground.
  • 4
    Sensor body inspection: If the wiring harness is normal, measure the sensor body resistance (refer to the workshop manual; typically several kilo-ohms to tens of kilo-ohms, depending on the model). If the resistance is infinite or zero, replace the sensor. Inspect the sensor for physical cracks or signs of water ingress.
  • 5
    Replacement and restoration: After installing a new sensor or repairing the wiring harness, verify the connector latch locks with an audible 'click'. Reconnect the battery, use the diagnostic tool to clear the fault code, and perform an 'SRS system self-check' or 'crash sensor configuration' (some models require writing the configuration code or learning the sensor position).
  • 6
    Verification test: Start the vehicle and confirm the SRS warning lamp turns off; read the data stream and confirm the sensor status displays as 'Normal'; perform a tap test (lightly tap the sensor mounting area and observe if the acceleration value in the data stream changes) and confirm system function has returned to normal.
Real-World Cases
BYD DTC AI Analysis

BYD Tang DM: Backed-out pin in right rear collision sensor connector causing intermittent fault

✓
The SRS warning light occasionally came on while driving and turned off after restarting. A VDS scan showed intermittent DTC B16EF. Inspected and found the sensor connector inside the right C-pillar trim was plugged in, but the terminals had backed out due to a previous improper repair, causing poor contact when driving over bumps. Re-crimped the terminals, applied conductive paste, and locked the connector fully. The fault has not reappeared.
Original source ↗
BYD DTC AI Analysis

BYD Song MAX: Open circuit in right rear impact sensor wiring harness after accident repair

✓
The vehicle had a right rear side scrape. After repairs at a workshop, the SRS warning light stayed on. Diagnosis showed current fault B16EF. Inspection revealed the accident had crushed and severed the wiring harness inside the right rear sill, breaking both power and signal wires. Repaired the harness by soldering and sealing with heat shrink tubing, rerouted the wiring to prevent chafing against metal edges, and cleared the fault codes. System returned to normal.
Original source ↗
BYD DTC AI Analysis

BYD Yuan EV right rear impact sensor internal short circuit after wading

✓
After water fording, the SRS warning light came on with DTC B16EF. Inspection revealed poor sealing of the right rear fender liner, letting water seep into the sensor mounting hole and causing a short circuit that damaged the sensor internally. Replaced the right rear impact sensor, cleaned corrosion and water ingress on the harness connector, and renewed the waterproof seal using a rubber gasket. Fault resolved.
Original source ↗
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.