AU
C052801

DTC C052801 indicates the Steering Angle Sensor (SAS) in the Intelligent Integrated Braking System (IPB) detects a steering angle value exceeding the valid system-calibrated range (typically ±720° or ±1440°, depending on vehicle calibration), or the sensor output signal voltage falls outside the normal 0 — Seal 6 EV

Braking System

DTC C052801 indicates the Steering Angle Sensor (SAS) in the Intelligent Integrated Braking System (IPB) detects a steering angle value exceeding the valid system-calibrated range (typically ±720° or ±1440°, depending on vehicle calibration), or the sensor output signal voltage falls outside the normal 0.5-4.5V range.

The Electronic Stability Control (ESC) system uses this key input sensor to determine the match between the driver's steering intent and the vehicle's actual yaw rate.

When the steering angle value exceeds this range, advanced driver assistance functions including ESC, ABS, Automatic Emergency Braking (AEB), and Lane Keeping may enter a degraded mode or fail completely, severely compromising vehicle handling stability.

Potential causes include a damaged sensor, an open circuit in the steering wheel clock spring, a Steering Column Control Module (SCCM) communication fault, an abnormal IPB internal signal processing circuit, or a missing SAS zero-point calibration following chassis repairs.

The C052801 fault code on the Seal 6 EV indicates the steering angle sensor is reporting a value or voltage outside the valid range. This is a medium severity issue because ESC, ABS, AEB, and lane keeping may be reduced or disabled. Common causes include a damaged steering angle sensor or a faulty clock spring ribbon cable. The recommended fix is to visit an authorised dealer for diagnosis and calibration. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Seal 6 EV
  • 1Damaged internal potentiometer or Hall element in the steering angle sensor (SAS), causing output signal drift or a fixed out-of-range value.
  • 2Internal ribbon cable in the steering wheel clock spring is broken or has poor contact, causing an intermittent open circuit in the sensor power supply, ground, or signal wire.
  • 3CAN bus communication fault between the steering column control module and the IPB (wiring short circuit, open circuit, or abnormal terminating resistor)
  • 4Failure to perform steering angle sensor zero-point calibration and end position learning using the dedicated diagnostic tool after a vehicle collision, chassis repair, or steering system removal and installation.
  • 5IPB (Intelligent Integrated Braking System) control unit internal angle sensor signal processing circuit fault or software calibration data loss.
What To Do
  • 1
    Connect the BYD dedicated diagnostic tool VDS2000, read the complete IPB system fault codes and freeze frame data, verify if the real-time Steering Angle value displays an invalid value (such as a fixed abnormal value of 8191° or -4096°), and check for related fault codes (such as C052901 Steering Angle Sensor Module Lost).
  • 2
    Check the steering wheel clock spring connector for looseness or corrosion. Use a multimeter to measure continuity in each clock spring circuit (especially the sensor 12V supply, GND, and signal wires). Turn the steering wheel and observe for sudden changes in resistance.
  • 3
    Measure the voltage at the steering angle sensor connector: verify the supply voltage is 12V±0.5V, ground resistance is less than 1Ω, and CAN-H and CAN-L voltages to ground are approximately 2.6V and 2.4V respectively. For analog signal sensors, verify the signal voltage changes linearly (0.5-4.5V) as the steering wheel turns.
  • 4
    Perform the steering angle sensor calibration procedure: center the steering wheel (front wheels straight ahead) and use the diagnostic tool to perform 'steering angle sensor zero-point calibration'; on some models, turn the steering wheel to the left and right limit positions, holding it at each position for 3-5 seconds to complete limit position learning.
  • 5
    If the calibration procedure fails or the fault remains, replace the steering wheel angle sensor or steering column control module assembly (on some models, the angle sensor is integrated into the clock spring or steering column module). Perform calibration again after replacement.
  • 6
    Clear the fault code and perform a road test. On a flat road surface, perform slalom and emergency lane-change tests. Confirm the ESC/ABS warning lamp remains off. Verify the steering angle sensor value in the diagnostic tool data stream changes accurately and in real time with steering wheel rotation (symmetrical left and right, close to 0° ±5° when centered).
Real-World Cases
BYD DTC AI Analysis

BYD Qin Pro DM steering wheel clock spring open circuit caused steering angle signal to exceed range

✓
The instrument panel ESC warning light stayed on. The diagnostic tool read IPB DTC C052801 (steering angle sensor value out of range). Live data showed the steering angle sensor fixed at 8191° (exceeding the upper limit) and unchanged by steering wheel rotation. Removed and inspected the steering wheel clock spring. Multimeter measurement showed infinite resistance between the sensor power terminal and the clock spring connector, confirming the internal ribbon cable was completely broken. Replaced the steering wheel clock spring assembly (Part No.: BYD-SAS-3602100). Performed steering angle sensor zero-point calibration and limit position learning. Cleared the fault codes and road tested; steering angle values returned to normal and ESC function was restored.
Original source ↗
BYD DTC AI Analysis

BYD Song PLUS DM-i steering angle sensor signal drift on cold start

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Owner reported that during autumn and winter, the dashboard occasionally displayed "Service brake system" when starting from cold. DTC C052801 (steering angle value out of range) set. The warning cleared automatically after 5-10 minutes of driving. Inspection found the steering angle sensor connector seal had deteriorated. Condensation formed inside in low temperatures, causing the sensor signal to drift when cold (spiking instantaneously above 900°). Removed the sensor connector, cleaned it with electronic contact cleaner, applied silicone-based conductive grease, replaced the waterproof seal and wrapped it with waterproof tape. Cleared the DTC and monitored for one week. The fault did not recur during cold starts.
Original source ↗
BYD DTC AI Analysis

Steering angle sensor not calibrated after accident repair on BYD Han EV

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The steering column assembly was replaced following a front-end collision. After the repair, the ABS and ESC warning lights stayed on and the vehicle wouldn't enter Ready mode (some models restrict this). The scan tool pulled IPB DTCs C052801 and C052901. Inspection showed the technician hadn't calibrated the steering angle sensor. The new sensor's zero point differed from the old unit, so the system flagged the steering angle as out of range. Using VDS2000, they ran "Steering Angle Sensor Zero Point Calibration" with the steering wheel centered and held, then performed "Limit Position Learning" (wheel full left and right lock). After a 15-minute road test, all warning lights went out and the fault codes cleared.
Original source ↗
BYD DTC AI Analysis

BYD Tang DM: Loose IPB module connector causing intermittent communication fault

✓
When driving on rough surfaces, the ESC warning light flashes intermittently with a buzzer alarm; operation is normal on smooth roads. Read DTCs C052801 and U012600 (lost communication with steering angle sensor module). Found the locking tab broken on the main connector for the IPB (Intelligent Integrated Brake System) control unit on the left side of the engine compartment, leaving approx. 2 mm of play. This interrupted the steering angle sensor CAN signal intermittently over bumps. Treated the connector pins (applied conductive grease to prevent oxidation) and secured the connector with cable ties and structural adhesive to ensure full engagement. Cleared the fault codes and road-tested on rough surfaces for 30 minutes. Fault did not return.
Original source ↗
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.B1737DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive). The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω). If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power. This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current. In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.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 Seal 6 EV →Seal 6 EV 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.