AU
U1332-00

DTC U1332-00 indicates the airbag control unit (SRS ECU) receives an abnormal or timed-out vehicle speed signal via the body CAN bus (B-CAN) — Atto 3

Safety System

DTC U1332-00 indicates the airbag control unit (SRS ECU) receives an abnormal or timed-out vehicle speed signal via the body CAN bus (B-CAN).

This fault occurs when the SRS module fails to receive a valid vehicle speed data frame from the instrument cluster or ABS/ESP module within the predetermined cycle, preventing the airbag system from determining collision severity based on real-time vehicle speed.

This safety system communication fault compromises the collision safety strategy, potentially causing airbag deployment timing deviations during high-speed collisions or false deployments during low-speed collisions.

5
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Fault in the instrument cluster internal CAN communication module or gateway, preventing transmission of the vehicle speed signal to the B-CAN network.
  • 2Damaged CAN transceiver inside the SRS control unit cannot receive or interpret vehicle speed data frames.
  • 3B-CAN network physical layer fault, including water ingress and oxidation at the G10/M40 connector, wiring harness damage causing a short or open circuit, or excessive contact resistance.
  • 4Abnormal network termination resistance (standard value approximately 60Ω; the SRS module and instrument cluster module provide this in parallel), causing signal reflection or attenuation.
  • 5Using a non-genuine instrument cluster or SRS module during accident repairs results in a CAN communication protocol mismatch or incompatible software version.
What To Do
  • 1
    Use the dedicated diagnostic tool to read the fault code and record freeze frame data. Confirm the vehicle speed, time, and environmental conditions when the fault occurred.
  • 2
    Visually check if the instrument panel vehicle speed display is normal to determine whether the fault is a signal source issue (no instrument panel display) or a transmission issue (instrument panel normal but SRS reports a fault).
  • 3
    Measure the CAN bus voltage at the diagnostic port: CAN-H should be 2.5-2.7V and CAN-L should be 2.3-2.5V. Confirm the bus physical layer base voltage is normal.
  • 4
    Disconnect SRS module connector G10 and measure the terminating resistance between terminals G10-2 (B-CAN-L) and G10-3 (B-CAN-H). The standard value is approximately 60 Ω (two 120 Ω resistors in parallel). If the resistance is abnormal, inspect the wiring section by section.
  • 5
    Check the SRS module power supply (constant power and ignition power) and ground circuits. Verify the voltage drop is less than 0.1V to rule out power supply interference causing communication interruption.
  • 6
    Use an oscilloscope to monitor the B-CAN waveform. Check for missing data frames, bit errors, ACK errors, or signal distortion. Focus on the G10 connector and the bend in the left A-pillar wiring harness.
  • 7
    Check CAN wiring insulation. Measure CAN-H and CAN-L resistance to ground and power supply. Inspect for water ingress corrosion or wiring harness wear causing intermittent short circuits.
  • 8
    Perform substitution testing: Replace the instrument cluster or SRS module with a unit of the same model. Observe if the fault code transfers to confirm the faulty component.
  • 9
    After repairing the wiring or replacing the faulty module, clear the fault code and perform a road test to verify the SRS system receives the vehicle speed signal in real time and the warning light is off.
Real-World Cases
BYD DTC AI Analysis

BYD S6 instrument cluster CAN module damage caused loss of vehicle speed signal

✓
The airbag warning light illuminated on the instrument cluster. The scanner retrieved DTC U1332-00. The speedometer displayed normal readings while driving, but the SRS system reported a vehicle speed fault. The technician checked B-CAN network communication with an oscilloscope and found it normal, but found that speed data frames sent from the instrument cluster to the SRS were occasionally lost. The technician traced the fault to the internal CAN communication module in the instrument cluster and replaced the assembly with a genuine part. Fault resolved.
Original source ↗
BYD DTC AI Analysis

BYD NEV precharge resistor failure caused CAN network failure

✓
The vehicle presented with a powertrain fault and multiple CAN communication DTCs including U1332-00. Diagnosis found a damaged front-end pre-charge resistor in the high-voltage battery pack, disrupting communication between the BMS and vehicle controller and affecting vehicle speed signal transmission across the CAN network. Replaced the pre-charge resistor and performed cell balancing on the battery pack. Network communication returned to normal and the U1332 DTC cleared.
Original source ↗
BYD DTC AI Analysis

Protocol mismatch caused by non-genuine instrument cluster in accident-repaired vehicle

✓
After accident repairs, the airbag warning light stayed on. Retrieved DTC U1332-00. Inspection found an aftermarket instrument cluster installed during the repair. The speedometer displayed correctly, but the cluster’s CAN protocol differed from the SRS module’s, so the SRS could not parse the vehicle speed data. Replaced the cluster with an OEM unit and reconfigured the SRS system parameters. Fault resolved.
Original source ↗
BYD DTC AI Analysis

BYD S6 left A-pillar wiring harness damage causing intermittent CAN-L short circuit

✓
On starting the vehicle after parking, the airbag warning light illuminated with DTC U1332-00 stored. Inspection found water stains on the G10 connector. Further investigation revealed the wiring harness beneath the left A-pillar had insulation damage from a previous accident repair, contacting the body metal and causing an intermittent short to ground on the CAN-L line. Repaired the damaged wiring, cleaned oxidation from the connector and applied waterproofing. Fault cleared.
Original source ↗
BYD DTC AI Analysis

Internal transceiver damage in SRS control unit caused vehicle-wide communication failure

✓
Multiple warning lights (ABS, SRS, ESP) illuminated simultaneously while driving. Scanner retrieved communication fault codes including U1332-00 and U0140. Using segmented troubleshooting, disconnected the SRS module; other systems returned to normal. Confirmed faulty CAN transceiver inside the SRS control unit continuously transmitting error frames and paralyzing the B-CAN network. Replaced the SRS control unit, recoded and matched it to the vehicle. Fault completely resolved.
Other Atto 3 Fault Codes
P0A0DBattery Energy Control Module Requested MIL IlluminationP0AA6Hybrid Battery Voltage System Isolation FaultP1A00Drive Motor "A" Performance — BYD proprietaryB1108For 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.
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.