P0172 on a 2022 Toyota Camry
Fuel System Too Rich (Bank 1)
What does P0172 mean on a 2022 Toyota Camry?
P0172 is set when the engine control module detects that long-term fuel trim on Bank 1 has been driven beyond approximately −25 % — the ECM is pulling out the maximum amount of fuel it is allowed to remove, and the oxygen sensor still reports a rich mixture. The cause is something delivering excess fuel or restricting air, or a sensor reporting a false rich signal.
Symptoms on a 2022 Toyota Camry
- Check Engine Light is illuminated
- Strong fuel smell from the exhaust
- Black smoke from the tailpipe under acceleration
- Poor fuel economy (sometimes severely worse — 30 %+ drop)
- Rough idle and hard starting (flooded condition)
- Fouled spark plugs from rich-running conditions
- Eventual catalytic converter damage (P0420 follows)
Likely causes on a 2022 Toyota Camry
- Leaking or stuck-open fuel injector(s) on Bank 1 Most commonEstimated repair: $150– $1,200
Drip-test individual injectors to find the leaker.
- Failed fuel pressure regulator allowing too much fuel CommonEstimated repair: $100– $400
- Restricted or dirty air filter / clogged intake CommonEstimated repair: $20– $80
- Failed MAF sensor over-reporting airflow CommonEstimated repair: $30– $350
- Stuck-closed EVAP purge valve (purge solenoid leaking fuel vapor) OccasionalEstimated repair: $80– $300
- Leaking fuel pressure regulator vacuum hose pulling fuel into the intake OccasionalEstimated repair: $20– $150
- Failed upstream O2 sensor biased rich OccasionalEstimated repair: $150– $450
- Engine oil contaminated with fuel (overdue oil change after rich running) RareEstimated repair: $80– $200
How to diagnose this on a 2022 Toyota Camry
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Read fuel trims at idle and 2500 RPM
A scan tool will show short-term (STFT) and long-term (LTFT) fuel trim. If LTFT is around −20 % or worse at all RPMs, the system is truly rich. If trims look normal at the scan tool, the issue may have been intermittent — pull freeze-frame data to see conditions when P0172 set.
Tools: Scan tool with live PIDs
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Inspect the air filter and intake tract
A heavily clogged air filter restricts airflow enough to push the mixture rich. Check the filter, the intake snorkel, and the throttle body for restrictions, soot buildup, or debris.
Tools: Common hand tools, Flashlight
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Check for fuel in the FPR vacuum hose
With the engine off, remove the vacuum hose from the fuel pressure regulator. Fuel inside the hose means the regulator diaphragm is ruptured and fuel is being drawn directly into the intake. Replace the regulator.
Tools: None
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Test injector spray pattern and balance
Use an injector test set, or measure fuel rail pressure drop while pulsing each injector individually with a scan tool. An injector that drops pressure significantly faster than its peers is leaking or flowing too much.
Tools: Scan tool with injector balance test, Fuel pressure gauge
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Verify MAF sensor airflow reading
A healthy MAF reads approximately 1 g/s per liter of displacement at idle (for example, ~3 g/s at idle on a 3.0-liter engine). Readings 30 %+ above that suggest the MAF is over-reporting airflow, which drives the ECM to add fuel.
Tools: Scan tool with MAF PID
Known Technical Service Bulletins for the 2020-2024 Toyota Camry
Manufacturers publish Technical Service Bulletins (TSBs) when a known issue affects a specific vehicle. These bulletins come from the NHTSA database for your Toyota Camry.
- ENGINE Feb 26, 2026
OBSOLETE NOTICE February 27, 2026: This bulletin is no longer applicable and is now obsolete.
NHTSA #11029896 - ELECTRICAL SYSTEM Jan 29, 2026
OBSOLETE NOTICE January 30, 2026: This bulletin is now obsolete. Please see T-SB-0001-26.
NHTSA #11028726 - ELECTRICAL SYSTEM Jan 27, 2026
Some 2018 – 2024 model year Toyota vehicles equipped with a Premium Audio with Dynamic Navigation System require a Special Service Tool (SST) USB flash drive to update the map, points of interest, and system software.
NHTSA #11028722 - UNKNOWN OR OTHER Jan 6, 2026
Some 2005 – 2026 Toyota vehicles that have undergone water intrusion may exhibit a condition in which a musty odor is present. Follow the procedures in this bulletin to remediate the odor and address this condition. The purpose of this Service Bulletin is to provide general guidelines and procedures for odor remediation. This Service Bulletin provides a guide on how to prepare and treat the interior of the vehicle for odor remediation. Refer to the applicable model and model year Repair Manual and the EPA (Environmental Protection Agency) website for the most up-to-date safety and precautionary guidelines.
NHTSA #11028712 - ENGINE Aug 6, 2025
The specific condition covered by this program is for a small engine coolant leak that can occur from the flow shut-off valve that can allow coolant to drip on other parts of the vehicle. This can cause "Engine Maintenance Required" to be displayed on the instrument cluster or cause the A/C not to function normally. Although the flow shut-off valve is covered by Toyota’s New Vehicle Limited Warranty for 36 months or 36,000 miles (whichever comes first), we at Toyota care about the customers’ ownership experience. Toyota is providing coverage for repairs related to Flow Shut-off Valve Coolant Leak.
NHTSA #11022949 - ELECTRICAL SYSTEM Jun 24, 2025
Some 2021 – 2022 model year Avalon, 2018 – 2024 Camry, 2019 – 2025 model year Corolla, 2022 – 2025 model year Corolla Cross, and 2019 – 2025 model year RAV4 vehicles with A25A-FKS and M20A-FKS engines may have a MIL ON condition with one or more of the following Diagnostic Trouble Codes (DTCs) upon cold soak start up with engine coolant temperatures between 14°F – 41°F: •P030027 – Random/Multiple Cylinder Misfire Detected (Emission) Signal Rate of Change Above Threshold •P030000 – Random/Multiple Cylinder Misfire Detected •P030100 – Cylinder 1 Misfire Detected •P030200 – Cylinder 2 Misfire Detected •P030300 – Cylinder 3 Misfire Detected •P030400 – Cylinder 4 Misfire Detected
NHTSA #11020670
+14 more TSBs available in MECH AI's TSB explorer for this vehicle.
Common fixes
- Replace leaking or over-flowing fuel injector(s)
- Replace the fuel pressure regulator
- Replace the air filter and clean the intake
- Clean or replace the MAF sensor
- Replace the EVAP purge valve
- Change engine oil if fuel-diluted
About the 2020-2024 Toyota Camry
The 2020-2024 Toyota Camry was commonly sold with the following powertrains: 2.5L I4, 3.5L V6, 2.5L Hybrid I4. Common trims include LE, SE, XLE, XSE.
How P0172 destroys catalytic converters
Sustained rich operation washes fuel past the rings into the oil, fouls spark plugs, and — worst of all — dumps unburned hydrocarbons into the exhaust. The catalytic converter tries to oxidize that fuel and overheats. Within weeks of driving with P0172 uncorrected, the catalyst can melt internally and set P0420 alongside. At that point you have two repair bills instead of one.
Rich condition vs. flooded engine
P0172 is a steady-state rich condition. A flooded engine — won’t crank, or cranks but won’t fire after a cold start — is a different problem (usually a leaking injector or bad cold-start enrichment logic). Both can set P0172, but flooding is more often acute and visible immediately at the key turn.
When the MAF is reading too high
A MAF that over-reports airflow makes the ECM think more air is entering than really is, so it adds extra fuel to match. This is one of the few P0172 causes that does not involve excess fuel — the fuel system is working correctly, the sensor is lying. MAF cleaning and unmetered-air inspections come before MAF replacement.