DTC P0138 — O2 Sensor Circuit High Voltage Bank 1 Sensor 2
DTC P0138 is a standardized diagnostic trouble code defined as "O2 Sensor Circuit High Voltage Bank 1 Sensor 2" within the Lambda / Cat Off subsystem. In DaVinci Deluxe Cloud Edition (v1.0.44), workshops can diagnose root causes or apply deterministic off-road/motorsport subsystem & path-level P0138 deactivation on a 100% virgin original ECU file.
🛟 24h/7 Live Engineering Support (365 Days / Including All Holidays): Direct step-by-step diagnostics & calibration engineering in every language (live logs, DTC scans, photos, videos & audio supported) until your car, 24V truck, tractor or marine vessel runs 100% flawlessly.
Engineering Breakdown for Fault Code P0138
| Diagnostic Parameter | Technical Specification for P0138 |
|---|---|
| Fault Code Identifier | P0138 (SAE J2012 / ISO 15031-6 Powertrain) |
| Official Definition | O2 Sensor Circuit High Voltage Bank 1 Sensor 2 |
| Primary ECU Subsystem | Lambda / Cat Off |
| Limp-Mode & Derate Impact | Activates ECU diagnostic fault class, illuminates Check Engine MIL, and restricts peak torque or closed-loop actuator control. |
| Workshop Pre-Check | Inspect harness continuity, +5V/+12V/+24V reference supply, live sensor plausibility, and mechanical component integrity before any software modification. |
| Off-Road / Motorsport Calibration | Upload a 100% virgin unmodified original ECU binary at https://www.davincideluxe.fr/online-ecu-tuning to apply complete Lambda / Cat Off calibration or selective path-level P0138 fault-class deactivation while keeping engine oil, temperature, and rail-pressure safety intact. |
Related OBD2, Euro 6d & 24V Diagnostic Trouble Codes (148)
Frequently Asked Technical Questions
What does fault code P0138 mean?
Diagnostic Trouble Code P0138 means "O2 Sensor Circuit High Voltage Bank 1 Sensor 2" and belongs to the Lambda / Cat Off monitoring subsystem.
What symptoms does P0138 cause on diesel or petrol ECUs?
Activates ECU diagnostic fault class, illuminates Check Engine MIL, and restricts peak torque or closed-loop actuator control.
How is P0138 calibrated safely in DaVinci Deluxe Cloud Edition (v1.0.44)?
After mechanical verification, upload a 100% virgin original Bench, Boot, or OBD ECU readout to DaVinci Deluxe Cloud Edition (https://www.davincideluxe.fr/online-ecu-tuning) to apply deterministic Lambda / Cat Off calibration or selective path-level P0138 deactivation with 24h/7 live engineering support.