AU
C008208

C008208 is a sub-fault code for the BYD ABS/ESP system — Qin Plus

Braking System

C008208 is a sub-fault code for the BYD ABS/ESP system.

C0082 indicates an abnormal brake system status, and sub-code 08 identifies the specific signal anomaly type.

The ABS (or ESP) control unit sends this abnormal brake system status warning to the instrument cluster.

It typically indicates abnormal communication signals between the control unit and the instrument cluster, key brake system sensor signals falling outside the valid range, or a protective warning triggered by prolonged continuous ESP intervention.

This DTC indicates the ABS/ESP system may fail to operate normally.

The vehicle will lose active safety functions including anti-lock braking, electronic stability control, and automatic emergency braking.

Conventional hydraulic braking typically remains unaffected.

The C008208 fault code on the Qin Plus indicates an abnormal brake system status signal in the BYD ABS/ESP system. Severity is medium because ABS, stability control, and automatic emergency braking may not work normally, although basic hydraulic braking usually remains. Common causes include poor ABS/ESP power or ground connections and CAN bus communication faults. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available from recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Loose connection, oxidation, or poor contact in the ABS/ESP control unit power supply or ground circuit, causing intermittent abnormal control unit operation.
  • 2CAN bus communication fault (including short circuit, open circuit, or signal interference on the powertrain CAN or chassis CAN), causing communication interruption or abnormal data between the ABS control unit, instrument cluster, and VCU.
  • 3Abnormal wheel speed sensor signal (damaged sensor, worn or shorted wiring, dirty magnetic ring) causing the ABS control unit to receive an implausible wheel speed difference signal.
  • 4Abnormal brake pedal position sensor (or brake light switch) signal due to installation misalignment, oxidized contacts, or poor wiring connections, resulting in incorrect pedal status recognition.
  • 5Instrument cluster internal receiving circuit fault or software version mismatch causing a false brake system fault warning.
What To Do
  • 1
    Connect the VDS diagnostic tool and read all fault codes. Check for accompanying C0031-C0048 (wheel speed sensor faults), C0051 (steering wheel angle fault), or U-class communication fault codes. Record the freeze frame data.
  • 2
    Check the status of the warning lights displayed on the instrument panel (ABS, ESP, EBD, brake system fault light), verify the fault symptom matches the DTC, and verify the brake fluid level is normal.
  • 3
    Check the power supply (constant power and ignition power) and ground wiring harness connectors for the ABS/ESP control unit (usually located in the engine compartment or near the cabin firewall). Measure the voltage to confirm it is within 12V ± 0.5V. Inspect the terminals for oxidation or backed-out pins.
  • 4
    Measure the voltage and waveform of the diagnostic CAN (CAN-H approx. 2.6–2.8 V, CAN-L approx. 2.2–2.4 V, terminal resistance approx. 60 Ω) and chassis CAN circuits. Inspect the wiring harness for wear or interference with the vehicle body.
  • 5
    Check the resistance of the four wheel speed sensors (approximately 1.0–1.5 kΩ) and the signal voltage (expect a 0–5 V AC voltage change when rotating the wheel). Check the gap between the sensor and the magnetic ring, and inspect the magnetic ring surface for dirt or damage.
  • 6
    Check the installation position of the brake pedal position sensor (or brake light switch), verify the switch on/off logic is normal, and inspect the wiring harness for wear.
  • 7
    Power reset the ABS/ESP control unit (disconnect the negative battery terminal for 5 minutes). After clearing the fault code, perform system calibration (including longitudinal acceleration sensor, lateral acceleration sensor, and steering wheel angle sensor calibration).
  • 8
    Perform a road test (including straight-line driving, turning, and braking tests) and observe if the fault code reappears. Use VDS to read the real-time wheel speed data stream and confirm there are no abnormal spikes.
Real-World Cases
BYD DTC AI Analysis

Loose ESP control unit connector causes intermittent C008208

✓
Symptoms: Dashboard intermittently displayed "Check ESP System" and "Check ABS System" warnings. DTC C008208 appeared sporadically, with increased frequency on rough roads. Brake pedal feel remained normal. Diagnosis: Scanned the brake system with VDS and retrieved DTC C008208; history showed it as a current fault. Brake fluid level was normal and live data from all four wheel speed sensors read normally. Inspected power and ground at the ESP control unit (left side of engine bay) and found poor contact at the main connector, a loose locking clip, and slightly oxidised internal terminals. Resolution: Re-seated the ESP control unit connector, cleaned the terminals with electronic contact cleaner, applied conductive grease, and replaced the locking clip to ensure a secure connection. Cleared the fault codes and completed a continuous 50 km road test; the fault did not reoccur.
BYD DTC AI Analysis

Worn right front wheel speed sensor wiring harness causing abnormal signal

✓
Symptoms: Dashboard suddenly displayed "Brake System Fault" while driving. ESP and ABS warning lights both lit up. Vehicle speed intermittently restricted (limp mode). Fault code: C008208. Diagnosis: Scanner showed only C008208 (Brake System Abnormal), no specific wheel speed sensor codes. Live data showed right front wheel speed signal fluctuating intermittently (2-3 km/h) while stationary. Raised the vehicle and found the right front wheel speed sensor harness rubbing against suspension components near the steering knuckle. Insulation worn through, causing intermittent short-to-ground in the signal wire. Solution: Cut out the damaged section of right front wheel speed sensor harness, resoldered connections, and insulated with heat shrink tubing. Rerouted and secured harness with cable ties to avoid suspension contact. Cleared fault codes and performed ABS dynamic test. Fault resolved.
BYD DTC AI Analysis

Misaligned brake pedal switch causing false signal

✓
Symptoms: At startup, dashboard displayed "Check braking system" with warning light on. Brake lights worked normally when pedal pressed; braking function normal. DTC C008208 stored. Diagnosis: Retrieved DTC C008208; no other codes present. Checked brake pedal position sensor live data: signal remained "pressed" when pedal fully released (normally closed contacts not opening). Found brake pedal switch mounting bracket deformed (switch located above pedal), causing insufficient clearance between switch and pedal linkage; switch did not fully release when pedal returned. Resolution: Adjusted brake pedal switch position until contacts opened properly with pedal fully released (faint click heard), then tightened mounting nuts. Ran brake system calibration (brake pedal position learning via VDS), cleared codes, road test normal.
BYD DTC AI Analysis

Faulty instrument panel CAN communication caused false fault signal reception.

✓
Symptoms: After starting the vehicle, the instrument cluster displayed a brake system fault and the ABS light stayed on. The diagnostic tool showed no fault codes in the ABS system; only the instrument cluster reported U-type communication faults (lost communication with ABS). Diagnosis: CAN bus voltage at the ABS control unit measured normal. At the instrument cluster, CAN-H and CAN-L voltages were both approximately 2.5V with no fluctuation, indicating a loose connection. Inspection revealed a backed-out terminal in the instrument cluster wiring harness connector X10 (behind the instrument cluster), causing unstable CAN signal transmission. Solution: Repaired the instrument cluster wiring harness connector X10, re-crimped the CAN wire terminals, and ensured proper seating. Cleared all system fault codes. The instrument cluster brake system warning light went off and C008208 did not reappear.
BYD DTC AI Analysis

Unstable battery voltage caused the ABS control unit to reset abnormally

✓
Symptoms: After sitting overnight, the vehicle started with the dashboard showing multiple system faults (ABS, ESP, brake system). Fault codes included C008208 and multiple U-class communication faults. Some warning lights cleared on their own after driving briefly. Diagnosis: Battery voltage measured 12.1V at rest (low) and dropped to 9.2V during cranking (too low). Checked the ABS control unit power supply and found severe oxidation at the battery negative ground point. This caused insufficient voltage to the control unit during startup, triggering a reset. Resolution: Cleaned and tightened the battery negative ground point, applied conductive grease to prevent oxidation, and replaced the aging battery (insufficient capacity). Startup testing showed voltage stayed above 11V. Cleared all fault codes with no recurrence.
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.