AU
C106600

DTC C106600 indicates missing or incorrect Steering Angle Sensor (SAS) calibration data, or that the calibration procedure was never performed — Seal U

Braking System

DTC C106600 indicates missing or incorrect Steering Angle Sensor (SAS) calibration data, or that the calibration procedure was never performed.

This sensor typically resides within the steering column or ESP control unit and monitors the steering wheel's absolute angle, rotation direction, and angular velocity in real time.

It serves as a core input signal for the Electronic Stability Program (ESP/ESC), Electric Power Steering (EPS), and Automatic Emergency Braking (AEB) systems.

The system triggers this fault code upon detecting a calibration data validation failure, or a significant deviation between the sensor's output angle and the theoretical zero position during straight-line driving (typically required to be within -5° to +5°).

Consequently, the ESP/ESC function enters a degraded or failure mode.

This may cause the vehicle to lose skid control during emergency avoidance maneuvers or on slippery roads; however, basic hydraulic braking functions typically remain unaffected.

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Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Failure to perform the steering angle calibration procedure after replacing the steering gear, steering column, steering wheel, or ESP control unit.
  • 2After a vehicle collision, chassis geometry parameters change or the steering angle sensor physical mounting position shifts, causing zero position mark misalignment.
  • 3Calibration data stored in the ECU non-volatile memory is lost after prolonged battery disconnection, abnormal system power supply voltage, or a control unit software upgrade.
  • 4Internal Hall element or photoelectric element failure in the steering angle sensor causes a mismatch between the output signal and the actual mechanical position.
  • 5Wheel alignment parameters (such as front toe and camber) are severely out of specification, preventing the steering wheel from mechanically centering during straight-line driving and exceeding the system compensation range.
What To Do
  • 1
    Pre-inspection preparation: Park the vehicle on level ground, check and adjust tyre pressure to the standard value, confirm the steering wheel is in the mechanical centre position (visually check the front wheels are straight or remove the steering wheel to check alignment marks), and clear unrelated fault codes.
  • 2
    Read data stream: Use BYD VDS or a generic diagnostic tool to access the Chassis/ABS/ESP system and read the Steering Angle Sensor (SAS) live data stream. Verify the angle value is within -5° to +5° during straight-line driving. If the deviation is too large, perform a mechanical adjustment or calibration.
  • 3
    Circuit inspection: Check the steering angle sensor connector for looseness (especially on accident-repaired vehicles). Measure the sensor supply voltage (should be 12V±0.5V), ground resistance (<1Ω), and CAN-H/CAN-L line voltage (approximately 2.5V, normal differential signal).
  • 4
    Sensor zero position check: For external steering angle sensors (such as Kostal), remove the sensor and verify the installation alignment mark aligns with the steering column zero position mark. If misaligned, reinstall the sensor.
  • 5
    Perform the calibration procedure: Use the diagnostic tool to access the special functions menu. Sequentially perform the yaw rate sensor calibration (if applicable), lateral acceleration sensor calibration (if applicable), and finally the steering angle sensor calibration (SAS Calibration/Steering Angle Learning). Verify the display shows 'Calibration successful'.
  • 6
    Verification and road test: Clear the fault code, start the vehicle, and verify the ESP/ESC warning light on the instrument cluster turns off. Perform low-speed straight-line driving and left and right steering tests. Confirm the data stream angle change matches the actual steering and no abnormal warnings appear.
Real-World Cases
BYD DTC AI Analysis

BYD Song Pro steering angle sensor calibration fault after accident repair

✓
Following accident repairs on a 2018-2020 BYD Song Pro, the instrument cluster ESP warning light stayed on and the multifunction video controller could not complete calibration. Technicians pulled codes U101586, C106600 (SAS not calibrated) and U12608 with a diagnostic tool, indicating a calibration fault in the ESP system. They first isolated the fault to the steering angle sensor based on the DTCs and tried recalibrating with the VDS diagnostic tool, but the procedure failed. They then checked the sensor power supply and CAN communication lines, finding no hardware faults. When removing the steering angle sensor (Keshida brand), they found the sensor mounting position had deviated from the zero-position mark—the positioning indicator was misaligned, so the system could not recognise the correct steering centre. Following the sensor installation specifications strictly, they reinstalled the steering angle sensor to the zero position, aligning the positioning indicator precisely with the zero mark. With the BYD VDS diagnostic tool reading real-time steering angle data, they ran the 'Steering Angle Sensor Calibration' routine. Once calibration finished, they cleared the fault codes and the ESP system returned to normal. The repair summary emphasizes that Song Pro steering angle sensors must strictly follow the zero-position indicator during installation, or fault code C106600 will recur.
Original source ↗
BYD DTC AI Analysis

BAIC Senova ABS/ESP System SAS Calibration Error (DTC C106600 Technical Reference Case)

✓
ABS/ESP warning light on; electronic stability program function limited. Scanned and retrieved DTC "C106600 SAS Calibration Error". Connected an Autel MS909EV to the chassis system and read the data stream. The steering angle sensor (SAS) showed an angle other than 0° while driving straight, indicating lost or incorrect calibration data. Needed steering angle relearning. Performed the steering angle learning procedure: enter [Common Special Functions] → select [Steering Angle Learning] → click [ABS (Anti-lock Braking System)/ESP (Electronic Stability System)] → select [Yaw Rate Sensor Calibration]. Confirmed the vehicle met the prerequisites (parked on level ground, steering wheel mechanically centered, vehicle stationary with no steering force applied), then clicked [OK]. Once the screen displayed "Calibration Complete", exited the program. DTC C106600 cleared successfully and the ABS/ESP system returned to normal.
Original source ↗
BYD DTC AI Analysis

BYD Qin/Tang/Han Series Steering Angle Sensor Zero Position Loss Fault (Technical Manual Case)

✓
After replacing the steering gear, steering column, or steering wheel, the instrument cluster displays "Check ESP System" or "Check ABS System", accompanied by heavy steering or ESP failure. The scan tool retrieves chassis system DTC C106600 (SAS not calibrated), sometimes with C005128 (SAS over-range) or C005154 (SAS not calibrated). Using the BYD VDS or a generic scanner, access the Chassis system and confirm the steering angle sensor current angle does not match the mechanical centre position (should read between -5° and +5°). Check the sensor plug connection, supply voltage (normal 12V), and CAN bus voltage (approx. 2.5V). Rule out wiring faults, then proceed with recalibration. First, centre the steering wheel mechanically (visually confirm the front wheels point straight ahead with the steering wheel centered). Use the scan tool to enter the "Chassis System" or "ESP System" and run "SAS Calibration" or "Steering Angle Learning". Some BYD models require this sequence: 1. Yaw rate sensor calibration; 2. Lateral acceleration sensor calibration; 3. Steering angle sensor calibration. Carry out a road test after successful calibration to confirm the ESP warning light turns off and the system operates normally.
Original source ↗
Other Seal U 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: Official This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.