OBD-II trouble code
P219B: Bank 2 Air/Fuel Ratio Imbalance
Application matters: P219B identifies an air/fuel-ratio imbalance on bank 2, not a specific cylinder or failed component. Locate bank 2 using the exact engine information. Companion-bank codes and available cylinder data can guide diagnosis but do not prove a local or shared cause.
The air/fuel-ratio monitor recorded an imbalance on bank 2. The code does not identify one guilty cylinder, rule out injectors or determine which repair applies to the vehicle.
Quick facts
- System
- Powertrain
- Category
- Fuel & Air
- 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 P2100–P219B, or start from the full code library.
What does P219B mean?
P219B reports an air/fuel-ratio imbalance on bank 2. It should not be read as a complete diagnosis of one cylinder or as a simple statement that the whole bank is lean or rich. The full code set, operating conditions and vehicle-specific monitor information determine which evidence the technician needs next.
Injectors remain a possible cause. Ford SSM 53336 covers some 2023–2025 Explorer and Aviator vehicles with the 3.0L EcoBoost engine, 15,000 miles or less, and P219A and/or P219B. Its service action is replacement of the injector assemblies only for the bank setting the code, under the workshop instructions. This is a bounded repair example, not an instruction to replace injectors on every vehicle with P219B.
Ford’s separate OBD operation summary lists conditions that must be met before its imbalance monitor runs. Those prerequisites are not proof that every injector, ignition component or sensor is physically healthy. A normal-looking fuel-trim snapshot also does not rule out the recorded imbalance or establish which cylinder caused it.
Available cylinder contribution, misfire or other comparison data may help the matched diagnostic sequence, but no single comparison is guaranteed to identify one failed cylinder. Likewise, P219A appearing with P219B does not establish a shared cause. Repair confirmation requires the actual monitor’s prerequisites and result, rather than an assumed driving duration or a cleared light.
Possible causes
- An injector or fuel-delivery fault demonstrated by the applicable procedure
- An intake, ignition or cylinder-mechanical fault affecting combustion
- A sensing or feedback fault established by the prescribed checks
- A vehicle-specific condition covered by an applicable service message
Symptoms
- Check-engine warning with P219B recorded
- Rough running, hesitation or a vibration on an affected engine
- Companion mixture or misfire faults requiring their own interpretation
- Abnormal comparison data when the applicable tests are performed
- No obvious running complaint despite the stored code
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.Preserve every full DTC, status and event record. Identify bank 2 from the exact engine information and record naturally occurring symptoms.
- 2.Check current service information for the vehicle and condition. If Ford SSM 53336 applies, follow its affected-bank injector action and workshop procedure rather than excluding injectors from consideration.
- 3.Have a qualified technician follow the prescribed fuel, air, ignition, sensing and mechanical sequence. A monitor prerequisite does not certify a component as healthy, and a lower-cost assumption should not set the test order.
- 4.Use available per-cylinder and bank data only as the applicable procedure defines. Do not treat one comparison or the presence of one/both bank codes as a conclusive fault-location test.
- 5.Leave fuel-system access, pressure testing, cylinder testing and connected electrical work to the qualified repairer with the required protected equipment. Do not unplug injectors or provoke a misfire yourself.
- 6.Repair the cause established by the applicable service action or diagnostic findings. Confirm the actual monitor result under its prerequisites and reassess any remaining faults.
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 check engine light 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 fuel-system testing; any high-pressure work also requires the prescribed pressure-release and handling precautions. Ask the technician what testing confirmed the repair.