OBD-II trouble code
P015B: O2 Sensor Delayed Response – Lean to Rich (Bank 1 Sensor 1)
Application matters: The Nissan example is limited to the specified 2018–2019 Rogue Sport J11/MR20DD condition with no drivability issues and the listed ECM part-number match. Ford separately illustrates lean-to-rich delay monitoring on its covered 2024–2025 gasoline applications.
The delayed transition is lean to rich at bank 1 sensor 1. Diagnosis must preserve that direction and the installed system; the code does not by itself prove a rich-running engine or a failed oxygen sensor.
Quick facts
- System
- Powertrain
- Category
- Emissions / Oxygen Sensor Response
- Severity
- Medium severity
- Driving guidance
- Depends on symptoms and vehicle guidance
- Repair cost range
- Get a vehicle-specific estimate after diagnosis.
- DIY difficulty
- Shop recommended
A code alone cannot establish whether driving is safe. Stop safely for a red brake or oil-pressure warning, overheating, severe misfire, stalling, or impaired braking or steering, and follow the owner's manual. Restraints faults can reduce crash protection even when the vehicle runs normally.
Browse every code in P0100–P0199, or start from the full code library.
What does P015B mean?
P015B identifies delayed lean-to-rich response at bank 1 sensor 1. Lean to rich describes the monitored transition, not a finding that the engine is currently too rich. The directional timing report must be interpreted with the complete fault record and the actual sensor/control system.
Its opposite-direction counterpart is P015A. A rich-to-lean result, a lean-to-rich result and a generic slow-response label should not be substituted for one another when recording the concern. Ford’s 2024–2025 gasoline summary explicitly separates directional time delay from response time constant in its front-sensor monitor. An arbitrary live reading does not reproduce those evaluations.
Nissan supplies a concrete service example in NTB18-047a, dated December 3, 2019. On listed 2018–2019 Rogue Sport J11 vehicles with the MR20DD engine, a specified P015A and/or P015B condition with no drivability issues can follow an ECM reprogramming path only after the current ECM part number matches the bulletin. The professional procedure also requires setup and final confirmation.
That eligibility check is a decision point, not a formality. If the part number does not match, or if the relevant reprogramming is not available, Nissan directs further diagnosis. Do not turn the update example into a declaration that the physical sensor, electrical path or exhaust must be healthy. A vehicle with running symptoms also needs its actual symptom diagnosis rather than an assumed no-drivability case.
Keep any separate rich-mixture, misfire or other companion report with its own evidence. P015B neither proves nor dismisses those faults. Ask the technician to identify bank 1 sensor 1 and the correct monitor before comparing signals or proposing a repair. The designation does not establish a universal physical side or sensor type.
Owner preparation is to save the full scan and describe conditions already observed. Leave hot-exhaust access, protected circuit work and calibration operations to qualified service. Do not create a rich condition, follow a road-monitor recipe or use a trial flash to diagnose it. Follow vehicle warnings, and arrange assistance for severe running symptoms or a stop instruction.
Possible causes
- The applicable Nissan ECM calibration case after all bulletin conditions are met
- Another confirmed signal, sensor or operating-response condition found through the vehicle-specific diagnosis
Symptoms
- A stored lean-to-rich delay report with the malfunction indicator
- Normal-feeling operation within the limited Nissan no-drivability example
- Running symptoms or additional mixture/response faults needing their own evaluation
Diagnostic steps
Save the full scan report, code status, and available freeze-frame data before clearing anything. Confirm the reporting module, any failure-type suffix, and the procedure for the exact vehicle. The steps below are an overview; use manufacturer specifications and safety procedures for testing.
- 1.Save the full code and event record, including whether P015A or separate mixture/misfire faults are also present.
- 2.Have the manufacturer’s lean-to-rich delay test and actual bank 1 sensor 1 identified; do not substitute an opposite-direction result.
- 3.Check application-specific service information. In the cited Nissan case, the repairer must verify the specified ECM part number and absence of drivability issues.
- 4.Require the matched further diagnosis if the calibration path is inapplicable. Any electrical, sensor or exhaust repair must follow demonstrated findings.
- 5.Have the confirmed work, required setup and verification completed professionally. Ask for a quote that explains each part of the repair rather than a generic sensor price.
Repair cost
Get a vehicle-specific estimate after diagnosis.
A trouble code alone does not price the repair. Ask the shop to identify the confirmed fault and itemize diagnosis, parts, labor, programming or calibration, and taxes.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with vehicle-specific fault and system diagnosis preselected. Adjust labor rate and vehicle category to fit your situation.
Related repairs
These links are planning examples; the code does not confirm that any listed part has failed.
DIY vs shop
A qualified shop is recommended because this can involve vehicle-specific emissions-system diagnosis and protected circuit or component tests, with pressure relief, exhaust cooling, fluid handling or setup when required by the installed system and confirmed repair. Ask the technician what testing confirmed the repair.