AU
B16E8-00

This DTC indicates a short to ground in the signal circuit of the Supplemental Restraint System (SRS) Middle Rear Impact Sensor — Qin Plus

Safety System

This DTC indicates a short to ground in the signal circuit of the Supplemental Restraint System (SRS) Middle Rear Impact Sensor.

The sensor mounts in the center of the rear bumper or rear longitudinal rail area.

Electrically, the insulation resistance between the sensor signal wire (typically a LIN communication or analog signal line) and body ground drops below the threshold (generally <1Ω).

This causes the SRS control unit (ACU) to continuously receive an abnormally low voltage signal.

This fault forces the SRS into fail-safe mode.

As a result, the system may fail to accurately detect rear impact acceleration, preventing the airbags, curtain airbags, or seat belt pretensioners from deploying in time during a rear-end collision.

Furthermore, the ACU may interpret the condition as a wiring fault and completely disable the rear impact monitoring function, illuminate the instrument panel SRS warning lamp, and downgrade the vehicle's passive safety system.

BYD Qin series models typically use a dual-axis accelerometer design for this sensor.

The ACU continuously registers a short to ground as 'abnormal circuit current' or 'signal voltage below lower limit'.

The B16E8-00 fault code on the Qin Plus indicates a high-severity short to ground in the SRS middle rear impact sensor signal circuit. This can disable rear impact monitoring and may affect airbag or seat belt pretensioner deployment in a rear collision. Common causes include damaged rear bumper wiring touching the body, or water entering the sensor. 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
  • 1Damaged wiring harness sheathing in the rear bumper area causes the wire to contact the metal body directly and short to ground (common after reversing collision repairs or underbody scrapes).
  • 2Rear center crash sensor body seal failure allows internal water ingress or moisture, causing the signal terminal to short to the sensor housing (ground).
  • 3Sensor connector (usually located inside the rear bumper or near the spare wheel well) loose, terminal pins backed out or corroded, causing the signal pin to short to ground at the connector housing.
  • 4Long-term vibration and friction wear the wiring harness insulation where it passes through body sheet metal holes or mounting brackets, causing contact with sharp metal edges.
  • 5Internal signal acquisition circuit fault in the SRS control unit (ACU), causing a false short to ground detection (rule out by substitution).
What To Do
  • 1
    Safety preparation: Disconnect the battery negative terminal and wait at least 3 minutes (or the time specified in the repair manual) to allow the SRS energy storage capacitor to fully discharge and prevent accidental airbag deployment.
  • 2
    Fault confirmation: Use VDS or a dedicated diagnostic tool to read all SRS fault codes, record freeze frame data, and confirm the fault is current (Present) rather than a history fault.
  • 3
    Locate the sensor: On BYD Qin models, the center rear impact sensor mounts to the inner side of the rear bumper reinforcement middle section, or below the spare wheel well. Remove the rear bumper inner trim panel to access the sensor.
  • 4
    Visual inspection: Check the sensor connector for looseness, water ingress, and oxidized or bent pins; check the wiring harness sleeve for wear at retaining clips and body panel holes.
  • 5
    Electrical measurement: Disconnect the sensor connector. Use a multimeter to measure the resistance between the harness-side signal wire and ground (normal: ∞ or >10kΩ). If continuity exists, trace the wiring backward. Measure the resistance between the sensor body signal terminal and the housing (normal: 2-3kΩ; close to 0Ω indicates a short circuit).
  • 6
    Wiring harness repair: If the wiring harness is damaged, repair the insulation layer using heat-shrink tubing or waterproof tape. Replace the wiring harness assembly if necessary. Maintain sufficient clearance (>20mm) between the wiring harness and body metal parts.
  • 7
    Component replacement: If the wiring harness is normal but the sensor is internally shorted, replace the center rear crash sensor (verify the part number for the specific vehicle model; the Qin series typically uses the crash sensor assembly).
  • 8
    System verification: Reconnect all connectors and the battery. Turn the ignition switch to ON. Clear the fault code using the diagnostic tool. Perform the SRS system self-check. Verify DTC B16E8-00 does not return and the instrument cluster SRS warning light turns off.
Real-World Cases
BYD DTC AI Analysis

After water ingress, an internal short in the sensor caused the SRS light to stay on.

✓
A 2017 Qin EV300 illuminated the SRS warning light after driving through deep water in heavy rain. Stored fault code: B16E8-00 (middle rear impact sensor short to ground). No collision damage was found on the rear bumper, but water had entered the sensor connector upon removal. The sensor’s signal terminal to housing resistance measured 0.3 Ω, confirming an internal short from water ingress. Replaced the middle rear impact sensor and waterproofed the connector with conductive grease and a waterproof cover, clearing the fault. Cause: deteriorated sensor seal allowed water to seep in through the connector gap during wading.
BYD DTC AI Analysis

Wiring harness chafing after accident repair caused intermittent fault.

✓
A non-authorised workshop repaired this 2018 Qin EV450 following a minor rear-end collision. One month later, the SRS warning light began illuminating intermittently. Diagnosis revealed DTC B16E8-00 as an intermittent active fault. Inspection of the rear impact sensor wiring harness routing found that the previous repair had not secured the harness correctly. A metal edge at the spare wheel well mounting bracket had cut through the insulation, allowing the wire to intermittently contact the body ground when driving over bumps. Repaired the damaged harness section, re-routed the wiring to specification, and protected it with a rubber protective sleeve, which completely resolved the fault.
BYD DTC AI Analysis

Connector corrosion caused signal short to ground.

✓
After three years of use in a coastal area, a 2017 Qin 100 showed an SRS warning light, with DTC B16E8-00 stored. Inspection found severe oxidation on the pins of the rear impact sensor connector (located inside the rear bumper). Green copper corrosion formed a low-resistance path (measured 12Ω) between the signal pin and the connector housing (ground). Cleaned the connector pins and socket, applied electronic contact cleaner, and replaced terminals where necessary. After cleaning, resistance returned to normal (>2kΩ). Cleared the DTC and the system returned to normal. Advised the owner to periodically check the sealing condition of underbody wiring harness connectors.
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.