AU
B1693-00

DTC B1693-00 indicates high resistance or an intermittent open circuit in the Supplemental Restraint System (SRS) Electronic Control Unit (ECU) ground circuit — Atto 8

Safety System

DTC B1693-00 indicates high resistance or an intermittent open circuit in the Supplemental Restraint System (SRS) Electronic Control Unit (ECU) ground circuit.

Specifically, the resistance of the ground path from the SRS ECU through connector G36 (specifically terminal G36-35) to the main body ground point exceeds the calibrated threshold (normally less than 1Ω).

This fault causes an unstable ECU power supply reference potential, triggers a system self-check failure, and continuously illuminates the airbag warning lamp (SRS lamp).

In extreme cases, this condition prevents airbag deployment during a collision or causes unintended deployment, severely compromising passive safety system functionality.

The B1693-00 fault code on the Atto 8 indicates high resistance in the airbag system (SRS) control unit ground circuit, causing an unstable power supply and warning light activation. This medium severity issue may prevent airbag deployment. Common causes include loose ground bolts or corroded terminals. Repair requires visiting an authorised dealer. Typical repair cost data is available from recorded cases.
3
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Ground point bolt loose or under-torqued: Long-term driving vibration loosens the SRS ECU ground bolt on the instrument panel frame or center tunnel, increasing contact resistance.
  • 2Ground point oxidation or corrosion: Wading, high humidity, or battery leakage causes the ground terminal to rust or oxidize, forming an oxide layer that obstructs current flow.
  • 3Internal damage to the ground wiring harness: Crushing or excessive bending during accident repairs breaks or partially breaks the internal copper strands, creating hidden high resistance.
  • 4Poor connector contact: G36 connector terminal backed out, loose, or corroded, causing poor contact with the ECU pin.
  • 5Improper treatment of the body ground terminal: Failure to remove paint, sealant, or coating from the body surface at the ground point after repairs results in a poor ground connection.
What To Do
  • 1
    Connect the BYD dedicated diagnostic tool (VDS or ED400) to read fault codes, confirm B1693-00 is present, and record freeze frame data.
  • 2
    Turn the power mode to OFF, disconnect the battery negative terminal, and wait at least 90 seconds for the SRS capacitor to fully discharge.
  • 3
    Locate the SRS ECU mounting position (usually below the center of the dashboard or behind the glove box) and find connector G36 and the body ground point.
  • 4
    Visually check the ground bolt tightness, inspect the ground wiring harness for damage or crush marks, and check the connector for water ingress or corrosion.
  • 5
    Disconnect connector G36. Use a multimeter to measure the resistance between terminal G36-35 on the wiring harness side and a clean metal part of the vehicle body. The standard value should be less than 1Ω.
  • 6
    If resistance exceeds the limit, remove the ground bolt. Use sandpaper (400-600 grit recommended) to sand the wiring harness terminal contact surface and the vehicle body ground surface. Completely remove the oxide layer, paint, and rust to expose shiny bare metal.
  • 7
    Apply conductive paste (anti-oxidation conductive compound) evenly to the contact surface. Reinstall the ground bolt and tighten to the specified torque (usually 10-12 N·m) to ensure secure installation.
  • 8
    If the wiring harness has breaks or internal damage, replace the ground wiring harness assembly from the SRS ECU to the body. Do not attempt repairs.
  • 9
    Remeasure the resistance between terminal G36-35 and ground, and confirm it stabilizes below 0.3 Ω.
  • 10
    Connect the battery negative terminal, set the power mode to ON, and use the diagnostic tool to clear the fault code. Check if the SRS warning lamp completes its self-check normally (illuminates for 6 seconds, then turns off).
  • 11
    Perform a road test or simulated vibration test to confirm the fault does not recur.
Real-World Cases
BYD DTC AI Analysis

Loose ground point on BYD S6/S7 causing SRS warning light

✓
Symptoms: After starting the vehicle, the SRS warning light on the dashboard stays on. The scan tool read DTC B1693-00 (poor ground connection). Diagnosis: The technician inspected the airbag ECU ground point (located near the dashboard frame) and found the ground bolt loose. They disconnected the G36 connector and measured 3.5Ω resistance between terminal G36-35 on the harness side and body ground (standard value should be less than 1Ω), indicating poor grounding. They also found slight oxidation on the ECU housing ground contact surface. Resolution: They removed the ground bolt and sanded the body ground end and harness terminal with sandpaper to remove the oxidation layer. They reinstalled and tightened the ground bolt to the specified torque of 10-12 N·m. They remeasured the resistance between G36-35 and body ground; it returned to 0.3Ω. They connected the diagnostic tool and cleared the fault code. After a normal self-check, the SRS light went out. Fault resolved.
Original source ↗
BYD DTC AI Analysis

BYD Qin: wiring harness damaged after accident repair caused B1693-00.

✓
After front collision repairs on a BYD Qin, the airbag warning light remained on. A scan tool retrieved DTC B1693-00 with the description "poor ground connection". The technician followed the Qin SRS diagnostic procedure for DTC B1693-00 and inspected the power and ground circuits for the airbag ECU. The ground point was not loose, but the resistance between terminal G36-35 and chassis ground fluctuated between 2Ω and 10Ω, and the voltage to ground was not 0V (indicating a voltage drop). Tracing the harness revealed it had been pinched during the accident repairs, partially breaking the copper strands inside the ground wire and causing poor contact. Replaced the ground harness assembly between the SRS ECU and the main chassis ground point. Remeasured the resistance between G36-35 and chassis ground; it stabilized at 0.2Ω (below the 1Ω specification). Verified the airbag ECU case ground was good. Cleared the DTC and road-tested the vehicle; the SRS light remained off and the system returned to normal.
Original source ↗
BYD DTC AI Analysis

Ground point oxidation fault on BYD Surui after wading through water

✓
Symptoms: The owner reported the airbag warning light illuminated on the instrument panel after driving through water. Diagnostic equipment retrieved fault code B1693-00 (poor earth connection). Other vehicle functions remained normal. Diagnosis: The technician consulted the BYD Surui SRS system fault code list and confirmed B1693-00 indicates an earth connection issue. The technician inspected the SRS ECU earth point located at the cabin floor (near the pedals) and found water stains and rust from the water ingress. The technician measured resistance between this earth point and the vehicle body at 15Ω, far exceeding the standard value (less than 1Ω), determining oxidation had caused poor earthing. The technician inspected connector G36 and confirmed the terminals showed no corrosion, though the earth bolt showed signs of rust. Solution: The technician thoroughly cleaned the earth point, used a dedicated cleaner to remove rust, and applied conductive paste to prevent further oxidation. If corrosion is severe, replace the earth bolt and earth terminal with new ones. After treatment, resistance dropped below 0.5Ω. The technician cleared the fault code; the SRS system self-test passed, and the warning light went out.
Original source ↗
Other Atto 8 Fault Codes
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.B110A02DTC B110A02 indicates the thermal management master control unit (HVAC ECU) or body control module (BCM) failed to receive valid CAN data frames from the PM2.5 air quality sensor over consecutive communication cycles (typically 500ms per cycle). The sensor typically mounts at the HVAC unit air inlet or behind the glove box and transmits real-time particulate concentration data (unit: μg/m³) to the HVAC controller via the CAN bus. The fault is essentially a communication link layer timeout. Potential causes include physical layer wiring faults, sensor power supply failures, sensor internal MCU lockup, or CAN network topology damage. Although this non-critical fault does not directly affect driving safety, it disables the intelligent air purification strategy and the automatic fresh air/recirculation switching function. In extreme cases, it triggers a thermal management system degraded mode, limiting compressor power or fixing the air flap position.B110B07This fault code indicates abnormal operation of the internal air pump (sampling pump) in the PM2.5 air quality detection module. The PM2.5 detector uses the laser scattering principle to measure particulate concentration and requires a built-in air pump to draw ambient air into the detection chamber at a constant flow rate. The ECU sets this code when it detects an open or short in the air pump drive circuit, abnormal current (stall or free-running), or abnormal speed feedback. This fault causes the automatic air conditioning system to lose air quality sensing capability, preventing automatic switching between fresh air and recirculation modes. The instrument cluster air quality display may show '--' or a fixed value, but the fault does not affect the vehicle powertrain or basic air conditioning cooling and heating functions.B173CDTC B173C indicates the Supplemental Restraint System (SRS) detects the Right Second Row Side Airbag squib circuit resistance exceeds the calibrated threshold (typically >4.5Ω). This fault is an active diagnostic result of the SRS system, indicating a high-resistance condition in the circuit between the Airbag Control Unit (ACU) and the airbag module. Causes for excessive resistance include increased contact resistance, a partially broken wiring harness, terminal oxidation, or an aging squib wire inside the airbag module. This fault causes the system to mark the airbag circuit as 'unreliable', meaning the airbag may fail to deploy during a collision. The fault typically illuminates the instrument cluster airbag warning light (SRS light) continuously, and some models also sound a warning buzzer.
Common problems reported for Atto 8 →Atto 8 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.