AU
U1332

DTC U1332 indicates the airbag control unit (SRS ECU) receives an abnormal or interrupted vehicle speed signal via the CAN bus — Qin Plus

Safety System

DTC U1332 indicates the airbag control unit (SRS ECU) receives an abnormal or interrupted vehicle speed signal via the CAN bus.

In BYD new energy vehicles, the ESP electronic stability system (or IPB intelligent integrated braking system) typically generates the vehicle speed signal and transmits it to the SRS module via the chassis CAN or powertrain CAN bus.

The SRS system relies on the vehicle speed signal for crash algorithm decisions: at low speeds, it may trigger only the seat belt pretensioners without deploying the airbags, while at high speeds, it requires multi-stage airbag coordination.

CAN bus communication interruptions, signal source module failures, or SRS module receiving circuit faults trigger this code.

This fault causes the airbag system to enter a degraded mode, which may prevent correct deployment during a collision or cause the warning lamp to remain illuminated.

The U1332 fault code on the Qin Plus indicates the airbag control unit is receiving an abnormal or interrupted vehicle speed signal over the CAN bus. Severity is medium because the airbag system may enter a degraded mode and may not deploy correctly in a crash. Common causes include an ESP/IPB braking system fault or wiring issues on the CAN-H or CAN-L lines. 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
  • 1ESP/ESC control unit (or IPB intelligent integrated braking system) fault preventing vehicle speed signal generation or transmission.
  • 2Open circuit, short circuit, or excessive contact resistance in the CAN-H or CAN-L line between the SRS control unit and the gateway/ESP
  • 3Gateway module (GW) fault prevents cross-network forwarding of the vehicle speed signal.
  • 4Damaged internal CAN transceiver circuit in the SRS control unit or software fault
  • 5Low 12V battery voltage or poor contact in the SRS system power supply/ground circuit causes abnormal CAN communication.
What To Do
  • 1
    Use VDS2000 or a dedicated BYD diagnostic tool to read fault codes. Confirm if U1332 is a current or history fault, and check for accompanying U-series communication fault codes (e.g., U1100 series).
  • 2
    Check the vehicle 12V battery voltage and SRS system fuses (usually located in the dashboard fuse box, e.g., F1/11, F2/16). Verify the power supply voltage is normal (12-14V).
  • 3
    Measure the resistance between pin 6 (CAN-H) and pin 14 (CAN-L) of the diagnostic connector (OBD). The standard value is approximately 60Ω (two 120Ω terminating resistors in parallel). If the resistance is abnormal (0Ω, 120Ω, or infinity), inspect the CAN bus wiring.
  • 4
    Inspect the CAN harness connectors of the ESP/IPB module, gateway module, and SRS module, specifically checking under the instrument panel and at the floor harness pass-through for water ingress, corrosion, or pin back-out.
  • 5
    Access the data stream function. Verify the ESP/IPB module outputs a normal vehicle speed signal, and simultaneously check the vehicle speed value the SRS module receives. If the ESP side is normal but the SRS side is abnormal, the fault is in the transmission path.
  • 6
    Disconnect the SRS module connector. Measure the CAN line voltage to ground (CAN-H approx. 2.6-2.7V, CAN-L approx. 2.3-2.4V) and harness continuity. If the voltage is abnormal, check the gateway module or wiring harness.
  • 7
    If wiring is normal, perform a power reset on the SRS module (disconnect the negative battery terminal for at least 5 minutes) or update the software. If the fault persists, replace the SRS control unit.
Real-World Cases
BYD DTC AI Analysis

Tang DM-i intermittent CAN vehicle speed signal loss

✓
2021 Tang DM-i intermittently displayed 'Check SRS System' while driving, with DTC U1332 intermittent. Found the floor wiring harness retaining clip below the left A-pillar loose; harness rubbed against the metal body edge and damaged the CAN-L wire insulation. Repaired and resecured the harness. Fault resolved. Front seat movement stresses the harness at this location.
BYD DTC AI Analysis

Faulty ESP module caused vehicle speed signal interruption in Yuan EV

✓
A 2019 BYD Yuan EV came in with DTC U1332 and the ABS warning light on. Diagnostics found an internal fault in the ESP module (Bosch 9.3) that stopped it sending vehicle speed frames to the CAN bus (ID:0x217). Replaced the ESP control unit and recalibrated; the SRS system then resumed normal communication. This case shows that vehicle speed signal source faults trigger cascading SRS faults.
BYD DTC AI Analysis

Song MAX Gateway Module Software Fault

✓
2019 Song MAX threw U1332 after collision repairs with the SRS light constantly on. Found the gateway module damaged in the crash—hairline cracks in the internal PCB were interrupting vehicle speed signal forwarding between powertrain and chassis CAN intermittently. Software update didn't fix it; replaced the gateway module and cleared the fault. Note: On accident-damaged vehicles, check the gateway mounting bracket for deformation.
BYD DTC AI Analysis

E1 EV wiring harness connector water ingress

✓
2020 BYD E1 threw code U1332 during the wet season; the undercarriage had been through water. Inspection found the GJK01 wiring harness connector for the SRS module beneath the floor had a perished seal that let water in, intermittently shorting CAN-H to the power supply. Cleaned the moisture, replaced the seal and connector terminals, cleared the fault. EVs need proper waterproofing on both high- and low-voltage harnesses.
BYD DTC AI Analysis

Qin Fuel SRS Module Internal Fault

✓
2020 BYD Qin (petrol) logged U1332 at 80,000 km with no other codes. CAN bus waveform normal; ESP vehicle speed signal output normal, but SRS module data stream showed 0 km/h. Internal CAN transceiver in SRS control unit faulty. Replaced SRS module and performed online configuration and coding. Recommend crash sensor calibration after replacement.
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.