P2195: O2 Sensor Signal Stuck Lean (Bank 1, Sensor 1)

What is P2195?

P2195 is a Diagnostic Trouble Code that means “O2 Sensor Signal Stuck Lean Bank 1 Sensor 1”.

This trouble code indicates an oxygen sensor issue. Bank 1 refers to the bank of the engine that houses cylinder #1, and Sensor 1 points to a malfunction in the upstream sensor.

The O2 sensor (oxygen sensor or the AF ratio sensor) helps the Powertrain Control Module or Engine Control Module monitor the air fuel ratio of the exhaust gas emissions. It’s located between the engine and the catalytic converter, and is usually a heated oxygen sensor.

Lean code P2195 shows up when the oxygen sensor detects less fuel or inaccurate fuel trim values in the system. It does so by comparing the oxygen particles in the exhaust gas and the air outside the sensor (that’s drawn to the AF ratio sensor).

These oxygen level differences cause voltage variations which the Engine Control Module monitors.

When there’s more oxygen in the exhaust gas, the Engine Control Module receives a low voltage signal. Whereas when the oxygen level is lower than the specific air fuel ratio, it gets a high voltage signal.

The Powertrain Control Module or Engine Control Module sets the code P2195 when the AF sensor reports an abnormal air fuel ratio.

Common symptoms

The most noticeable DTC P2195 symptoms are poor engine performance and fuel inefficiency.

That’s because with a P2195 code, the Engine Control Module thinks that your engine isn’t running on enough fuel (running lean.) So it’ll keep dumping extra fuel, ultimately affecting the engine performance.

Here are a few more symptoms of code P2195:

• An illuminated Check Engine Light
• An overheating engine
• Decreased fuel efficiency
• Engine misfires
• Rough idle

Can I still drive?

Driving with P2195 will probably be uncomfortable due to the rough idle. But the P2195 trouble code can become severe if you neglect it.

As the code prompts the Engine Control Module to inject extra fuel into the air-fuel mixture, it may eventually lead to damage in the car engine and other major components like the catalyst converter and O2 sensor, not to mention also causing poor fuel economy.

So it’s best to get the P2195 code resolved at the earliest possible.

P2195 causes

DTC P2195 is usually caused by a problem in the O2 sensor signal. 

Here are some reasons why a code P2195 may show up:

• Faulty oxygen sensor: This happens when the O2 sensor doesn’t work correctly and shows a lean reading.
• Wiring issues in the O2 sensor circuit: An issue with the oxygen sensor wiring means it’ll be unable to send signals to Powertrain Control Module.
• Sensor heater malfunction: This results in inaccurate detection of oxygen concentration as only an adequately heated oxygen sensor can detect O2 particles.
• Fuel injection malfunction: Faulty fuel injection causes the air fuel ratio to deviate from the normal range.
• Exhaust leak: This may result in false AF sensor readings, showing a lean condition.
• Large engine vacuum leak: This may cause unmetered air to enter the combustion chamber, affecting the air fuel ratio.
• Positive Crankcase Ventilation (PCV) system malfunction: Fault code P2195 may show if the PCV system is faulty or if there’s a leak in the PCV valve.
• ECT sensor malfunction: a faulty Engine Coolant Temperature sensor would send false signals, which alters the air fuel ratio.

Other causes include:

• Air suction or air leaks in the air intake system
• Too high or low fuel pressure

Diagnosis

Code P2195 may be caused by a sensor heater malfunction, a faulty fuel injector, a bad spark plug, or air leaks.

But self-diagnosing these DTC P2195 causes can be risky, so it’s best to have an expert look at your vehicle to avoid misdiagnosis.

Your mechanic may do the following checks to diagnose the P2195 code:

1. Your mechanic may scan for any other fault code using an OBD-II scanner. They’ll also monitor long, and short-term fuel trim values or air fuel ratio readings.
2. Then they may visually check for any damaged wiring in the O2 sensor circuit. They may also inspect the vacuum line for a leak or crack.
3. If the check engine light and the code still persists, your mechanic may check if the mass air sensor (MAF sensor) needs cleaning.
4. The mechanic may look for a fuel injector, hose, or exhaust leak between the mass air sensor and the throttle body.
5. They may inspect the O2 sensor. If your vehicle has more than one bank, the mechanic might move the defective sensor to another bank to note any changes in the code. If there isn’t, they’ll likely replace the oxygen sensor.
6. If DTC P2195 still shows up, they may monitor the fuel pressure. If it’s low, they may replace the fuel pressure regulator or fuel pump.

Possible repairs for P2195 & Costs

Based on the diagnosis of fault code P2195, your mechanic may do the following repairs:

• If your mechanic finds the MAF sensor contaminated, they may clean or replace it.
• They may repair the damaged connector or wiring of the oxygen sensor.
• Your mechanic may fix a vacuum leak or intake air tubes if it has cracks or disconnections.
• The mechanic may replace the fuel pressure regulator or fuel pump.
• If the engine light persists, your mechanic will replace oxygen sensor 1 bank 1. To replace the sensor, the exhaust pipes need to be cool. They’ll unscrew the old sensor, disconnect all electrical wires, install the new sensor, and wire back all connectors.

Repair cost:

Oxygen sensor replacement costs differ according to your car’s make and labor charges in your area. Typically, the replacement costs may be around $338 to $387. This includes both labor costs ($61 – $77) and the cost of spare parts like a new sensor ($277 – $310).