AU
U014608

DTC U014608 indicates a CAN communication data length error between the Intelligent Power Brake (IPB) system and the vehicle gateway — Qin Plus

Braking System

DTC U014608 indicates a CAN communication data length error between the Intelligent Power Brake (IPB) system and the vehicle gateway.

In the UDS diagnostic protocol, U0146 indicates abnormal communication with the Body Control Module (BCM) or gateway.

The suffix '08' specifically indicates an invalid data frame length or a Bus Off state.

This fault occurs when the data packet length sent by the IPB module mismatches the gateway module reception protocol, or when an abnormal CAN physical layer signal causes a data frame parsing failure.

Because the IPB controls brake boost, energy recovery, and Electronic Stability Control (ESC), this fault may limit ABS/ESP functions, cause abnormal brake pedal feel, and disable Automatic Emergency Braking (AEB).

Severe cases compromise driving safety.

When this fault occurs, the vehicle typically enters a degraded mode, limiting specific driver assistance functions.

The U014608 fault code on the Qin Plus indicates a CAN communication data length error between the Intelligent Power Brake system and the vehicle gateway. Severity is medium because braking support, ABS/ESP, energy recovery, or AEB may be limited. Common causes include an IPB CAN transceiver or software fault, or a gateway parsing fault. The recommended fix is to visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
5
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1IPB module internal CAN transceiver fault or software version defect causing the module to send abnormal-length data frames.
  • 2Gateway controller internal fault; unable to correctly parse brake system data sent by the IPB.
  • 3Poor contact, short circuit, or open circuit in the gateway wiring between the brake system CAN bus (powertrain network) and the body CAN bus.
  • 4Unstable power supply voltage to the IPB or gateway module (below 9V or above 16V) causes abnormal communication chip operation.
  • 5Aftermarket electronic equipment (such as dash cams or ambient lighting) interferes with the CAN bus signal, or wiring harness modifications cause abnormal bus termination resistance.
What To Do
  • 1
    Use the BYD VDS diagnostic tool to read the complete fault codes, check for accompanying communication faults such as U0140 and U0121, and record the freeze frame data.
  • 2
    Check the IPB module power supply: Measure the voltage at pin 1 (constant power) and pin 6 (IGN power) of connector K148. The voltage should be 12 ± 0.5 V. Measure the ground resistance at pin 5. The resistance should be less than 1 Ω.
  • 3
    Check the gateway module power supply: Locate the gateway controller at the lower left of the dashboard and check the G2H connector for normal power and ground.
  • 4
    Measure the power CAN (P-CAN) bus voltage: Disconnect the battery negative terminal. Measure pins 6 (CAN-H) and 14 (CAN-L) at the diagnostic connector; terminal resistance must be approximately 60 Ω. Power on the vehicle. CAN-H voltage must be 2.5-3.5 V, and CAN-L voltage must be 1.5-2.5 V.
  • 5
    Check the communication circuit between the IPB and the gateway: inspect instrument panel wiring harness connectors G2H and G2K for backed-out pins, corrosion, or poor contact.
  • 6
    Update the IPB and gateway module software to the latest version using VDS online programming to eliminate software defects.
  • 7
    If the wiring is normal, replace the IPB module, then bleed and calibrate the brake system. If the fault persists, replace the gateway module and reconfigure the network parameters.
Real-World Cases
BYD DTC AI Analysis

BYD Song PLUS DM-i: Intermittent IPB gateway communication loss

✓
While driving, the instrument cluster suddenly displayed "Brake System Fault" and "Check ESP", and the ABS and ESC warning lights illuminated. The fault cleared after a restart but recurred intermittently. VDS retrieved DTCs U014608 and U012108 (Lost Communication with IPB). Inspection found the CAN-H pin on the IPB module G2K connector had backed out 0.5mm, causing poor contact and incomplete data frame transmission when driving over bumps. After reseating the pin and applying conductive adhesive, the fault did not recur during 200km of continuous road testing.
Original source ↗
BYD DTC AI Analysis

Tang DM gateway module hardware fault causing abnormal braking system communication

✓
Vehicle could not enter Ready mode. Instrument cluster displayed "Brake System Fault". VDS could not access IPB system, with DTC U014608 and multiple gateway communication fault codes stored. Measured gateway module G2H connector ignition voltage at only 9.2V, below normal. Found instrument panel fuse box G2H connector loose. Tightened connector; voltage returned to normal but U014608 remained. Replaced gateway module and performed online configuration. Fault resolved. Root cause: damaged internal CAN transceiver unable to correctly parse IPB data length.
Original source ↗
BYD DTC AI Analysis

Han EV: Aftermarket equipment interference caused IPB data length error

✓
After installing a non-genuine dashcam (powered from the OBD port), the owner experienced frequent brake system warnings while driving. The scanner read U014608. Removing the device cleared the fault. Deep inspection revealed an internal circuit fault in the dashcam: it continuously sent abnormal voltage signals to the CAN bus (peaking at 5.5V), causing data frame checksum failures during IPB-gateway communication and triggering length errors. Removing the modified equipment and restoring the factory OBD wiring resolved the fault.
BYD DTC AI Analysis

Qin Pro DM IPB software defect causes communication fault

✓
When starting the vehicle at -10°C, the instrument cluster displayed a brake system fault. VDS read code U014608. Checked the wiring harness and power supply; both were normal. Consulted the BYD Technical Service Bulletin (TSB) and confirmed the IPB controller's early software version had a bug causing abnormal initialization data frame length during cold starts. Performed an IPB software upgrade using VDS (V1.2 to V1.5). Ran 10 cold-start tests after the upgrade; the fault did not recur.
BYD DTC AI Analysis

Song Pro discharged battery causing IPB communication error

✓
Vehicle sat parked for three days and failed to start. Jump-started; the dashboard displayed multiple system faults including U014608 (Gateway data length error). Battery voltage tested at only 10.8V with 45% health. Replaced the battery and cleared most fault codes, but U014608 returned intermittently. Found a 0.3V drop on the IPB module constant power circuit caused by oxidized battery terminals. Cleaned the terminals, applied anti-corrosion grease, and tightened the ground cable. Fault eliminated.
Original source ↗
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.