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U012608

DTC U012608 indicates the ABS/ESP control unit receives an abnormal CAN bus data frame or detects a checksum failure from the Steering Angle Sensor (SAS) — Seal 6 EV

Braking System

DTC U012608 indicates the ABS/ESP control unit receives an abnormal CAN bus data frame or detects a checksum failure from the Steering Angle Sensor (SAS).

This fault is a communication data integrity error, not a simple signal timeout.

The ABS module flags "corrupted data" when it detects a CRC error in the SAS data packet, an abnormal Data Length Code (DLC), or a signal value outside the physically reasonable range.

This fault causes the vehicle's Electronic Stability Program (ESP), Traction Control System (TCS), and Automatic Emergency Braking (AEB) to enter a degraded mode or fail completely.

Some models trigger power limitation (limp mode), severely compromising driving safety.

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Cases Logged
Real-World Cases
BYD DTC AI Analysis

Replaced damaged steering angle sensor assembly on BYD Song

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A BYD Song had the ESP and traction control warning lights on with no throttle response. Current DTC U012608 (Lost Communication With Steering Angle Sensor). Removed the steering wheel and checked the steering angle sensor connector on the column. Pins 1-2 had normal power and ground, ruling out wiring. Internal chip failure in the sensor was causing data frame errors. Replaced the sensor with an OEM unit and ran the calibration procedure in VDS. Fault cleared, ESP system normal.
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BYD DTC AI Analysis

Song MAX: Wiring Corrosion Repair on Flood-Damaged Vehicle

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A flood-damaged BYD Song MAX displayed "Please check ESP system" on the dash, the ESP warning light was on, and acceleration was weak. Retrieved fault codes U012608, P0228, P2122, and U010008; they returned soon after clearing. Inspection found severe oxidation and corrosion in multiple bus connectors in the engine bay and cabin. Cleaned the steering angle sensor connector and chassis CAN bus connection points, and repaired the damaged wiring harness. After the wiring repair, used a dedicated diagnostic tool to recalibrate the yaw rate system and steering angle position sensor (Launch X431 and Autel tools cannot complete this calibration). Fault completely resolved.
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BYD DTC AI Analysis

Song CAN bus and ECM communication fault

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While driving, the BYD Song's engine and ESP warning lights suddenly illuminated with limited power. DTCs U010008 (ECM CAN data corrupted) and U012608 were stored. The technician checked the CAN bus waveform with an oscilloscope and found noise indicating communication faults. Troubleshooting traced this to a poor connection in the CAN bus wiring. After repairing the connection, the technician checked and upgraded the ECM software and recalibrated the steering angle sensor. Power returned and the communication DTCs did not return.
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BYD DTC AI Analysis

Diagnostic tool compatibility issue and sensor calibration

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2020 BYD Song reported DTC U012608. A generic scan tool could not locate the fault or clear the code. The technician switched to a BYD-specific diagnostic tool and found the generic unit accessed incorrect vehicle configuration settings, causing false positives. Disconnect the battery negative terminal for five minutes to clear intermittent faults. For persistent faults, confirm the wiring is normal first, then perform steering angle sensor calibration using the dedicated diagnostic tool; otherwise the fault light stays on even after replacing the sensor.
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Other Seal 6 EV 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: Community This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.