AU
B16C7-00

DTC B16C7-00 indicates an internal fault or communication error in the SR8 panoramic image control unit (360° surround-view system ECU) — Seal U

Safety System

DTC B16C7-00 indicates an internal fault or communication error in the SR8 panoramic image control unit (360° surround-view system ECU).

This ECU typically mounts on the right side of the trunk or inside the center console.

It processes video signals from the front, rear, left, and right surround-view cameras to enable the bird’s-eye view, dynamic guide lines, dashcam, and reversing camera functions.

This DTC triggers when the ECU self-check detects a processor fault, memory error, unstable power supply, or CAN network communication interruption, forcing the system into fail-safe mode.

The multifunction display may go black, show a "Panoramic System Fault" warning, or display only a single camera view.

Although this fault does not affect the powertrain or driving safety, the vehicle loses parking assistance functions, increasing the risk of a reversing collision.

This fault frequently occurs in BYD Song series (Song Pro, Song MAX, Song PLUS) and early Qin EV models.

Diagnostic tools often mislabel it as an "SRS_ECU fault"; it is actually an SR8 system fault.

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Cases Logged
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Causes
Likely Causes — Seal U
  • 1SR8 ECU power supply circuit fault: Blown fuse EF20/EF22, poor ACC relay contact, or loose constant power line causing ECU operating voltage to drop below 9V or exceed 16V.
  • 2ECU internal hardware damage: Overheated main processor (usually NXP or Renesas chip), cold solder joints on DDR memory chips, or image processing DSP chip failure. Prolonged high-temperature operation or unstable voltage typically causes these faults.
  • 3Software program error: System firmware corruption, calibration data loss, program runaway, or system crash. Commonly occurs after prolonged vehicle power disconnection or interrupted OTA updates.
  • 4CAN bus communication fault: Short circuit, open circuit, or abnormal terminating resistor (standard 60Ω) in the CAN-H/CAN-L lines between the SR8 ECU, gateway, and multimedia head unit, preventing ECU recognition.
  • 5Environmental factors: Water ingress at ECU mounting location (boot leak), poor heat dissipation triggering overheat protection, capacitor failure during extreme low-temperature startup.
What To Do
  • 1
    Initial inspection: Confirm the fault symptom. Check for a black 360° panoramic view screen or reversing camera image failure. Use VDS2000 or Launch X431 to read all fault codes. Check for accompanying fault codes B16C8 (camera fault) or U0140 (communication fault).
  • 2
    Power supply system check: Measure the voltage at pin 1 (constant B+) and pin 24 (ACC) of the SR8 ECU connector; the voltage should be 12V ± 0.5V. Verify secure connections at ground points G202/G203. Check fuses EF20 (10A) and EF22 (15A) in the fuse box for blown elements.
  • 3
    Network communication check: Measure the resistance between OBD connector pins 6 (CAN-H) and 14 (CAN-L). The resistance should be approximately 60 Ω. Check the CAN line waveform at SR8 ECU connector pins 19 and 20. A normal waveform shows a 2.5V baseline with a superimposed square-wave signal.
  • 4
    ECU self-check and restart: Disconnect the battery negative terminal for more than 5 minutes, or unplug the SR8 ECU connector, wait for the capacitors to discharge, and reconnect. Observe if the fault temporarily clears. Attempt to perform 'SR8 system calibration' and 'camera calibration' using the diagnostic tool.
  • 5
    Software flash: Use the BYD dedicated diagnostic tool to flash the SR8 ECU program (version must match vehicle model year). After flashing, perform camera calibration and surround-view stitching calibration.
  • 6
    Hardware replacement: If the previous steps fail, replace the SR8 panoramic image control module (part number varies by model, e.g., 5A-3600100 for Song Pro DM-i). After replacement, perform: ① Online configuration parameter writing ② Four-camera calibration ③ Steering wheel angle sensor calibration.
Real-World Cases
BYD DTC AI Analysis

Song Pro DM-i 360-degree surround view system intermittently blacks out and restarts

✓
Owner reported that the 360° surround view screen would suddenly go black while driving, recover after a restart, but recurred frequently. VDS scan retrieved DTCs B16C7-00 (SR8 ECU fault) and B16C8-00 (right front camera communication fault). Inspection found the SR8 ECU mounted inside the right-hand boot trim panel. Voltage testing showed the ACC supply dropping from 12V to 8V over bumps. Found the fuse holder terminals oxidised and loose. Replaced the EF22 fuse and holder, cleaned the wiring harness connector, and resolved the fault. One-month follow-up: no recurrence.
BYD DTC AI Analysis

Qin EV450 complete reversing camera failure with warning light

✓
The owner reported no image on the centre screen when selecting reverse, with only 'panoramic system fault' displayed. The diagnostic tool retrieved B16C7-00 (history) and U0140-00 (lost communication with SR8). Inspection revealed slight water staining on the SR8 ECU housing at the left side of the boot. Disassembly showed electrolytic corrosion on the internal PCB where the conformal coating was damaged. The root cause was an aged, leaking boot seal. Replaced the SR8 control module (PN 5A-3600100), addressed the leak, and resealed with sealant. Programming and calibration restored function.
BYD DTC AI Analysis

Song MAX surround view camera stitching misalignment after update

✓
The vehicle developed stitching misalignment in the 360-degree panoramic view after the dealership performed an OTA update to the multimedia system, with front and rear camera images failing to align while the system logged fault code B16C7-00. Initial diagnosis indicated incomplete SR8 ECU firmware writing during the upgrade. Repair procedure: Using VDS2000, accessed 'Special Functions' > 'SR8 System Maintenance', executed 'Software Downgrade', then reflashed the latest firmware (V2.3.8). Then entered 'Camera Calibration' mode and used the dedicated calibration cloth to recalibrate the front, rear, left and right cameras. After calibration, stitching accuracy returned to normal. Cleared fault codes and the issue has not recurred.
BYD DTC AI Analysis

Song Plus EV: 360 system freezes on cold start

✓
Cold starts on winter mornings caused the 360-degree surround view system to fail to initialise, with the centre touchscreen freezing at the loading screen. Normal operation resumed after 10 minutes of warming up. Retrieved DTC B16C7-00 (SR8 ECU internal fault). Checked ECU power supply and earth — normal. Measured the ECU internal crystal oscillator and found startup time extended at low temperatures (-5°C), causing abnormal processor reset. This is a hardware defect affecting early production batches. Solution: Replaced the SR8 ECU with an improved unit (hardware version V1.2 or higher, improved crystal oscillator circuit) and flashed low-temperature compensation firmware. After replacement, 10 cold-start tests performed, all normal.
Other Seal U 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.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.B110AThis DTC indicates interrupted CAN bus communication or abnormal data between the air conditioning control unit (ACU) and the PM2.5 air quality sensor. The PM2.5 sensor monitors particulate concentration inside and outside the vehicle and provides the basis for purification control in the automatic air conditioning system. The ACU triggers this fault if it fails to receive a valid CAN message from the sensor within the specified period (usually 100-500 ms), if message verification fails, or if the signal frame times out. Although this fault does not affect vehicle driving safety, it disables the automatic air purification function. The air conditioning system cannot automatically switch between recirculation and fresh air modes or activate the air purification mode based on air quality. A persistent fault may restrict the thermal management strategy.
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.