AU
C006202

DTC C006202 indicates the IPB (Intelligent Integrated Braking System) detected an abnormal longitudinal acceleration sensor signal — Qin Plus

Braking System

DTC C006202 indicates the IPB (Intelligent Integrated Braking System) detected an abnormal longitudinal acceleration sensor signal.

This sensor measures the vehicle’s longitudinal acceleration (deceleration) G-value.

It provides a key input signal for the coordinated control of Electronic Stability Control (ESC), the Anti-lock Braking System (ABS), Automatic Emergency Braking (AEB), and the energy recovery system.

BYD DMi models typically integrate this sensor within the IPB assembly or mount it on the chassis as an independent inertial sensor.

A signal fault causes these safety systems to enter a degraded mode or fail, affecting driving stability, particularly during emergency braking and handling on slippery roads.

5
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1IPB assembly internal longitudinal acceleration sensor hardware fault (chip damage, cold solder joint, or aging drift)
  • 2Poor contact, open circuit, or short circuit in the sensor power supply, ground, or signal wiring (especially chassis wiring harness damage after wading or bottoming out)
  • 3Outdated IPB control unit software or missing calibration data causes abnormal signal processing.
  • 4Sensor mounting position shifted or internal micromechanical structure damaged after a vehicle collision or severe chassis impact.
  • 5Extreme temperatures or electromagnetic interference cause the sensor signal to momentarily exceed the tolerance range, triggering the fault code.
What To Do
  • 1
    Use a VDS or BYD dedicated diagnostic tool to read the complete fault codes and freeze-frame data. Check for accompanying C006164 (lateral acceleration) or other IPB-related fault codes. Verify the longitudinal acceleration live data stream reads within ±0.1G when the vehicle is stationary.
  • 2
    Visually inspect the IPB assembly and chassis wiring harness connectors (especially the G03 connector under the vehicle) for water ingress, oxidation, loose connections, or mechanical damage. Measure the sensor supply voltage (usually 5V or 12V, depending on model year) and signal wire resistance.
  • 3
    Perform longitudinal acceleration sensor zero-point calibration: Access IPB system special functions using the diagnostic tool and select 'Longitudinal Acceleration Sensor Zero-Point Calibration'. Park the vehicle on a level surface, center the steering wheel, and follow the prompts to complete learning (some models require automatic learning while driving).
  • 4
    If calibration fails, disconnect the battery negative terminal for 5 minutes, clear the fault code, and power on the vehicle for a self-check. If the fault recurs, verify the IPB ground point (located in the front compartment or on the chassis side member) is secure. If necessary, sand the ground point and apply conductive paste.
  • 5
    Replace the IPB assembly: If diagnostics confirm an internal sensor fault (integrated design), replace the entire IPB brake master cylinder assembly. After replacement, bleed the system, perform calibration and longitudinal acceleration sensor zero-point learning, and conduct a road test to verify ABS/ESC functions.
Real-World Cases
BYD DTC AI Analysis

BYD Song Plus DM-i ESC warning light on after water wading, C006202 intermittent

✓
A 2021 Song PLUS DMi with 20,000 km showed intermittent ABS and ESC warning lights after the owner drove through heavy rain and floodwater. The scan tool logged current fault code C006202. Live data showed the longitudinal acceleration signal fluctuating between 0.5G and 1.2G (normal: 0±0.1G). Raising the vehicle on a hoist revealed water stains and green corrosion inside the chassis IPB harness connector G03. We cleaned the connector, applied insulating silicone grease, dried the harness internals with compressed air, and reconnected it. The fault cleared. Check underbody sealing and fit a harness protective sleeve if required.
BYD DTC AI Analysis

C006202 persists after accident repairs; replace the IPB.

✓
After replacing the front bumper and underbody shields during accident repairs, the dashboard displayed 'Braking System Fault'. Scanned DTC C006202; it would not clear. Inspection found the IPB assembly sustained minor impact in the collision. Externally undamaged, but the internal longitudinal acceleration sensor MEMS chip had failed. Data stream showed longitudinal acceleration fixed at 2.4G regardless of vehicle movement. Since the sensor is integrated in the IPB and not available separately, replaced the IPB assembly and performed longitudinal acceleration zero-point calibration. Fault resolved.
BYD DTC AI Analysis

Software fault caused signal drift; upgraded IPB software to resolve.

✓
A 2022 Song Pro DMi frequently triggered DTC C006202 during normal driving on flat roads. Checks of the wiring harness and sensor data stream showed no obvious abnormalities; the code cleared but returned after 10 km. BYD technical service bulletins confirmed an IPB control unit software defect in this VIN range, causing abnormal longitudinal acceleration signal filtering. Fix: Upgrade the IPB control unit software using VDS2000 to the latest version (must be newer than the March 2023 release), then perform sensor zero-point learning. The fault did not recur after a 30 km road test.
BYD DTC AI Analysis

Aftermarket underbody shield pinched wiring harness, causing interference

✓
After the owner had an engine undershield fitted at a non-authorised workshop, the ESC warning light came on. Diagnosis revealed active DTC C006202. Inspection showed the installer had not torqued the aftermarket shield to specification; its edge compressed the IPB longitudinal acceleration sensor harness, causing the signal wire to short intermittently to ground. The technician repositioned the shield, fitted rubber buffer pads between the shield and harness, and repaired the crushed insulation to clear the fault. Technicians should note the impact of underbody modifications on chassis wiring.
BYD DTC AI Analysis

Sensor zero-point lost after extended storage; recalibrated

✓
A Song PLUS DM-i parked for three months displayed DTC C006202 and a "Check Brake System" warning upon restart. The vehicle had no collision or water ingress history, and wiring inspection found no faults. Prolonged 12V battery depletion caused the IPB control unit to lose its stored longitudinal acceleration zero-point calibration data. Repair: Connected a diagnostic tool, accessed the IPB system, and performed "Longitudinal Acceleration Sensor Zero-Point Calibration." Completed the calibration as prompted, cleared the DTC, road-tested with hard acceleration and hard braking, confirmed normal ESC operation, and delivered the vehicle.
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.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.