The P2272: O2 Sensor Signal Stuck Lean Bank 2 Sensor 2 indicates that the oxygen sensor on bank 2, sensor 2, is consistently reading a lean condition. This sensor monitors the amount of oxygen in the exhaust gas and helps regulate fuel injection. A lean condition means there’s too much oxygen compared to the fuel. This could be due to various reasons, such as an exhaust leak, a faulty oxygen sensor, or problems in the fuel system.
P2272 quick overview
| Meaning | P2272: O2 Sensor Signal Stuck Lean Bank 2 Sensor 2 |
| Is it serious? | This code can be serious as it may affect vehicle emissions, fuel efficiency, and engine performance. |
| Possible causes | – Faulty or contaminated oxygen sensor – Exhaust leaks near the sensor – Issues with the fuel system, leading to a lean condition – Wiring or electrical connection problems – Malfunctioning Powertrain Control Module (PCM) |
| How to diagnose? | Inspect O2 Sensor: Check the condition of the oxygen sensor and its connections. Check for Exhaust Leaks: Look for leaks in the exhaust system, especially near the sensor. Evaluate Fuel System: Assess the fuel pressure and injectors for proper operation. Examine Wiring and Connectors: Look for damaged or corroded wiring and poor connections. Conduct a Smoke Test: Perform a smoke test to find any hard-to-detect exhaust leaks. PCM Diagnostic: Consider PCM testing if other diagnostics do not reveal the issue. |
P2272 Meaning
In simple terms, the P2272 code means that your vehicle’s computer is getting a signal that there’s too much air or not enough fuel in part of the exhaust system. This can cause your car to run less efficiently, produce more emissions, and might lead to other engine problems. It’s usually related to the oxygen sensor, but it could also be a sign of leaks in the exhaust or issues with how the engine is getting or using fuel. It’s important to get this checked out to keep your car running well and avoid more serious problems down the road.
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How to fix P2272 – learn from mechanics
I looked into P2272 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Audi
Vehicle Information: 2014 Audi S7 4.0L
Issue + Repair History: Initially came in with a whistling noise due to excessive vacuum in the crankcase. Oil separator replaced to resolve noise issue. However, the check engine light reappeared with four DTCs. Subsequently, boost sensor 2 was replaced, but the faults persisted. No leaks were found in a smoke pressure test.
Other OBD2 Codes + Test Results:
- P0507 – Idle control system RPM higher than expected
- P2098 – Post cat oxygen sensor Bank 2 too lean
- P2272 – Oxygen sensor B2S2 too lean
- P0240 – Boost sensor 2 implausible signal
Suggestions to Fix Issue:
- Inspect turbo inlet pipe for damage to the check valve
- Test for internal vacuum leaks, particularly in the PVC system
- Examine fuel trims while blocking vacuum from the intake to PVC
Final Fix: Resolved by identifying and repairing a broken wire in the harness connector to the boost pressure sensor. After replacing the connector housing and all three pin wires, the vehicle was tested multiple times with no faults reoccurring.
Case #2: Ford
Vehicle Information: 2004 Ford F-150 FX4 5.4L
Issue + Repair History: Vehicle came in with codes P0171, P0174, P2195, P2107, and P2272. After replacing the upper intake gaskets-seals, spark plugs, cleaning the MAF sensor, TBI bore and plate, and clearing codes, the vehicle ran fine with a smooth idle. However, code P2272 appeared as pending during a road test. Further troubleshooting included replacing the O2 sensor, testing wiring and PCM connections, and inspecting the catalytic converter.
Other OBD2 Codes + Test Results: P2272- B2S2 lean
Suggestions to Fix Issue:
- Resistance test all four O2 wires (signal, signal return, VPWR, and heater) for continuity and shorts
- Check for terminal pin fitment at PCM and O2 sensor
- Swap rear O2 sensors side to side to diagnose if the issue follows the harness
- Consider the possibility of an exhaust leak, misfire, or catalytic converter issue
- Check the cat with a heat gun to verify it is getting up to temperature
Final Fix: Problem was initially solved by running a new signal wire from B2S2 to the PCM. However, this led to B1S2 reading 0.000V. After additional wire testing and replacements, the problem persisted. Ultimately, switching the O2 sensors side to side revealed that the B1S2 sensor was faulty. Replacing this sensor normalized all readings and resolved the issue.
Case #3: Mercedes
Vehicle Information: 2009 Mercedes-Benz E350 4Matic 3.5L
Issue + Repair History: The vehicle had persistent check engine light issues with codes P0038, P0141, P2270, P2272, P2195, and P2271. Initially, both rear O2 sensors’ heaters were found to be open and were replaced. The Mass Air Flow (MAF) sensor was also replaced due to rich and lean codes. Despite these replacements, the codes returned. The vehicle then had all four O2 sensors replaced.
Other OBD2 Codes + Test Results: P0038- LR O2 Heater P0141- RR O2 Heater P2270- RR O2 Aging P2272- LR O2 Aging P2195- RF O2 Lean P2271- B1S2 Rich
Suggestions to Fix Issue:
- Check the ECM box cover for tightness and the ECM connector for corrosion
- Verify proper installation of air filter housing and conduct a smoke test for any fuel mixture codes
- Consider the possibility of a Motor Electronics Module replacement
- Ensure the use of original equipment (O.E.) sensors, as aftermarket sensors may not work well
- Consider re-flashing/software update of the Motor Electronics
Final Fix: The issue was resolved by discovering water in the rear mufflers, which was shorting the O2 sensors. The vehicle had no drain holes in the mufflers, causing water accumulation from short trips and a sloped garage. Drilling drain holes in the mufflers and replacing all four O2 sensors resolved the problem.
Case #4: Chevrolet
Vehicle Information: 2008 Chevrolet Silverado 1500 WT 4.3L
Issue + Repair History: The truck was running roughly with check engine light and reduced engine power light on. It had multiple codes including P0172, P0175, P0068, P0101, P2272, P2270, and others related to MAP sensor, TP sensor, idle speed, intake air flow, and HO2S signals. Initial repair attempts included replacing the coolant temperature sensor and mass airflow sensor. Fluctuations were observed in MAF readings, coolant sensor, TPS, and TAC command. Fuel pressure was slightly higher than the standard range.
Other OBD2 Codes + Test Results:
- P0172– Fuel trim rich bank 1
- P0175 – Fuel trim rich bank 2
- P0068 – Throttle body airflow performance
- P0101 – Mass air flow sensor performance
- P2272- Ho2s signal stuck lean bank 2 sensor 2
- P2270– Ho2s signal stuck lean bank 1 sensor 2
- Fuel pressure koeo – 60 psi
- Fuel pressure koer – 64 psi
Suggestions to Fix Issue:
- Checking and replacing throttle body and MAF sensor
- Inspecting wiring harness for damages or rubbing
- Checking and cleaning all grounds, especially at the battery
- Testing power and ground to the PCM
- Considering possible throttle body problems and performing idle learn
- Checking reference circuits for anomalies
Final Fix: The issue was resolved by replacing the ECM after extensive testing. The customer took the truck to the dealer for ECM replacement under warranty.
Case #5: Chevrolet
Vehicle Information: 2009 Chevrolet Traverse LTZ 3.6L
Issue + Repair History: The shop vehicle initially set a DTC for a post-catalytic O2 sensor’s heater short. All four O2 sensors were replaced. The MIL stayed off for several weeks, then intermittently came on. Exhaust leaks were checked with no findings. Fuel trims were good, and no vacuum leaks were found. A joint at the catalytic converter was re-welded due to moisture seeping, but no exhaust leaks were detected. The vehicle was smoked, and a TSB concerning exhaust leaks was reviewed.
Other OBD2 Codes + Test Results:
- P2099- Lean
- P2272
Suggestions to Fix Issue:
- Checking O2 sensors and considering replacing them again
- Ensuring there are no exhaust leaks using soap bubbles and regulated low shop air
- Checking the front O2 against the rear O2 at steady light load conditions
- Pressurizing the exhaust with shop air and using soap and water to check for leaks
- Investigating the fuel system and MAF sensor more closely
- Considering fuel injector issues or MAF sensor concerns
Final Fix: The issue was resolved by replacing the ECM after about 2 weeks of testing at the dealership. The vehicle was still under warranty, and this resolved the problem.
How to diagnose P2272
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Advice | Diagnostic Step |
|---|---|
| Check O2 Sensors | Inspect and potentially replace the O2 sensors, particularly the one related to the fault code. |
| Investigate Wiring and Connectors | Examine the wiring and connectors for any damage, corrosion, or loose connections. |
| Perform Smoke Test | Conduct a smoke test to identify any potential exhaust leaks. |
| Check Fuel Trims | Monitor fuel trims to assess if the vehicle is running rich or lean, indicating potential issues with the fuel system. |
| Inspect Exhaust System | Thoroughly inspect the exhaust system, including the catalytic converter, for any signs of damage or blockages. |
| Verify Sensor Functionality | Test the affected O2 sensor’s functionality with diagnostic tools to ensure it’s operating correctly. |
| Consider PCM/ECM Issues | If all other tests are inconclusive, consider potential issues with the Powertrain Control Module (ECM/PCM). |
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko