AU
B16E8-00

This DTC indicates a short to ground in the signal circuit of the Supplemental Restraint System (SRS) Middle Rear Impact Sensor — Atto 8

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 Atto 8 indicates a high-severity short to ground in the SRS middle rear impact sensor signal circuit. This can disable rear impact monitoring, turn on the SRS warning light, and affect airbag or seat belt pretensioner operation in a rear-end crash. Common causes include damaged rear bumper wiring or water ingress in the sensor. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
3
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Damaged wiring harness sheath in the rear bumper area allows direct wire contact with the metal body, causing a short to ground (common after reversing collision repairs or underbody scrapes).
  • 2Rear center crash sensor body seal failure; internal water ingress or moisture causes the signal terminal to short to the sensor housing (ground).
  • 3Sensor connector (usually located inside the rear bumper or near the spare wheel well) is loose, or terminal pins are backed out or corroded, causing the signal pin to short to ground against the connector housing.
  • 4Long-term vibration and friction wear the wiring harness insulation where it passes through body panel holes or mounting brackets, causing contact with sharp metal edges.
  • 5Internal fault in the SRS control unit (ACU) signal acquisition circuit causing a false short-to-ground detection (rule out by substitution).
What To Do
  • 1
    Safety Preparation: Disconnect the battery negative terminal. Wait at least 3 minutes (or the time specified in the repair manual) to fully discharge the SRS energy storage capacitor 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 historical.
  • 3
    Locate the sensor: On the BYD Qin, the center rear impact sensor mounts to the inner middle section of the rear bumper reinforcement 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 the 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 >10 kΩ). If continuity exists, trace the circuit backward. Measure the resistance between the sensor body signal terminal and the housing (normal: 2-3 kΩ; short circuit: close to 0 Ω).
  • 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 has an internal short circuit, replace the center rear crash sensor (verify the part number for the specific vehicle model; for the Qin series, this is usually the crash sensor assembly).
  • 8
    System verification: Reconnect all connectors and the battery. Turn the ignition switch to ON. Use the diagnostic tool to clear the fault code. Perform the SRS system self-check. Confirm B16E8-00 does not return and the instrument cluster SRS warning light turns off normally.
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 Atto 8 Fault Codes
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.B110A02DTC B110A02 indicates the thermal management master control unit (HVAC ECU) or body control module (BCM) failed to receive valid CAN data frames from the PM2.5 air quality sensor over consecutive communication cycles (typically 500ms per cycle). The sensor typically mounts at the HVAC unit air inlet or behind the glove box and transmits real-time particulate concentration data (unit: μg/m³) to the HVAC controller via the CAN bus. The fault is essentially a communication link layer timeout. Potential causes include physical layer wiring faults, sensor power supply failures, sensor internal MCU lockup, or CAN network topology damage. Although this non-critical fault does not directly affect driving safety, it disables the intelligent air purification strategy and the automatic fresh air/recirculation switching function. In extreme cases, it triggers a thermal management system degraded mode, limiting compressor power or fixing the air flap position.B110B07This fault code indicates abnormal operation of the internal air pump (sampling pump) in the PM2.5 air quality detection module. The PM2.5 detector uses the laser scattering principle to measure particulate concentration and requires a built-in air pump to draw ambient air into the detection chamber at a constant flow rate. The ECU sets this code when it detects an open or short in the air pump drive circuit, abnormal current (stall or free-running), or abnormal speed feedback. This fault causes the automatic air conditioning system to lose air quality sensing capability, preventing automatic switching between fresh air and recirculation modes. The instrument cluster air quality display may show '--' or a fixed value, but the fault does not affect the vehicle powertrain or basic air conditioning cooling and heating functions.B173CDTC B173C indicates the Supplemental Restraint System (SRS) detects the Right Second Row Side Airbag squib circuit resistance exceeds the calibrated threshold (typically >4.5Ω). This fault is an active diagnostic result of the SRS system, indicating a high-resistance condition in the circuit between the Airbag Control Unit (ACU) and the airbag module. Causes for excessive resistance include increased contact resistance, a partially broken wiring harness, terminal oxidation, or an aging squib wire inside the airbag module. This fault causes the system to mark the airbag circuit as 'unreliable', meaning the airbag may fail to deploy during a collision. The fault typically illuminates the instrument cluster airbag warning light (SRS light) continuously, and some models also sound a warning buzzer.
Common problems reported for Atto 8 →Atto 8 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.