Symptoms
For this DTC, the malfunction indicator light (MIL) illuminates. There may be other symptoms.
Causes
Potential causes of a P2195 code include:
- Malfunction of the oxygen sensor (O2) or A/F ratio sensor or sensor heater
- Open or shorted O2 sensor circuit (wiring, harness)
- Fuel pressure or fuel injector issue
- Faulty PCM
- Intake air leaks or engine vacuum leaks
- Faulty fuel injector(s)
- Fuel pressure too high or too low
- PCV system leak/failure
- Faulty A/F sensor relay
- MAF sensor malfunction
- ECT sensor malfunction
- Fuel pressure too low
- Fuel leak
- Air intake in the air intake system
Diagnostic Steps and Possible Solutions
Use a scan tool to obtain sensor readings and monitor short-term and long-term fuel trim values and O2 sensor or air/fuel ratio readings. Also look at freeze frame data to see the conditions when the code was set. This should help determine if the AF O2 sensor is functioning properly. Compare with manufacturer values.
If you don’t have access to a scan tool, you can use a multimeter and probe the O2 sensor wiring connector terminals again. Check for shorts to ground, shorts to power, open circuits, etc. Compare specifications with manufacturer specifications.
Visually inspect the wiring and connectors leading to the sensor, look for loose connectors, rubbed/chafed wires, melted wires, etc. Repair if necessary.
Visually inspect the vacuum lines. You can also test for vacuum leaks using propane or carburetor cleaner along the hoses while the engine is running; if the RPM changes, you’ve probably found the leak. Be very careful if you do this, and have a fire extinguisher handy in case of problems. For example, on many Ford vehicles, the hose from the PCV to the throttle body can melt, causing P2195, P2197, P0171 and/or P0174 codes. If a vacuum leak proves to be the problem, it would be wise to replace all vacuum lines if they are aging, becoming brittle, etc.
Use a digital volt ohmmeter (DVOM) to check the proper operation of other mentioned sensors such as MAF, IAT.
Perform a fuel pressure test, check readings against manufacturer specifications.
If you are on a tight budget and only have an engine with more than one bank and the problem is only on one bank, you can swap the sensor from one bank to the other, clear the code and see if the code follows to the other bank. This would tell you that it is the sensor/heater itself that has failed.
Check for outstanding Technical Service Bulletins (TSBs) for your vehicle; in some cases, the PCM may be recalibrated to fix this issue (not a common solution though). TSBs might also call for sensor replacement.
When replacing oxygen/AF sensors, be sure to use high-quality sensors. In many cases, non-OEM sensors are of lower quality and will not function properly. We strongly recommend sticking with OEM brand replacements.