P2196 O2 Sensor Signal Stuck Rich Bank 1 Sensor 1
OBD-II Trouble Code Technical Description
O2 A/F Sensor Signal Biased/Stuck Rich (Bank 1 Sensor 1)
What does that mean?
This code is a generic powertrain code. It is considered generic because it applies to all makes and models of vehicles (1996-newer), although specific repair steps may be slightly different depending on the model.
On some vehicles, such as Toyotas, this is actually referring to A/F sensors, Air/Fuel ratio sensors. Which are basically more sensitive versions of oxygen sensors.
The powertrain control module (PCM) monitors the air/fuel ratio of the exhaust using oxygen (O2) sensors, and tries to keep things at the normal air/fuel ratio of 14.7:1 via the fuel system. The oxygen A/F sensor outputs a voltage reading that the PCM uses. This DTC is set when the air/fuel ratio as read by the PCM has strayed so far from 14.7:1 that the PCM can no longer correct it.
This code specifically refers to the sensor between the engine and catalytic converter (not the one behind it). Bank #1 is the side of the engine that contains cylinder #1.
Note: This DTC is very similar to P2195, P2197, P2198. If you have multiple DTC codes, always fix them in the order they appear.
Symptoms
For this DTC, the malfunction indicator lamp (MIL) will illuminate. There may be other symtoms.
Causes
Potential causes of a P2196 code include:
Diagnostic Steps & Possible Solutions
Use a scan tool to get readings from the sensor, and monitor the short and long term fuel trim values and O2 sensor or Air Fuel Ratio sensor readings. Also, look at the freeze frame data to see the conditions at the time the code was set. That should help determine if the O2 AF sensor is operating correctly. Compare with manufacturers values.
If you don’t have access to a scan tool, you could use a multimeter and back-probe the terminals on the O2 sensor wiring connector. Check for shorts to ground, short to power, open circuits, etc. Compare specs with manufacturers specifications.
Visually inspect the wiring & connectors leading to the sensor, check for loose connectors, wires rubbed/chaffed, melted wires, etc. Repair as necessary.
Visually inspect vacuum lines. You can also test for vacuum leaks using propane or carburetor cleaner along the hoses while the engine is running, if the RPMs change you likely found the leak. Be very careful if doing that, and have a fire extinguisher within reach in case something goes wrong. If a vacuum leak is determined to be the problem, it would be prudent to replace all vacuum lines if they are getting older, becoming brittle, etc.
Use a digital volt ohm meter (DVOM) to check other sensors mentioned such as MAF, IAT, for proper operation.
Perform a fuel pressure test, verify readings against manufacturers specification.
If you’re on a budget and you only have an engine with more than one bank and the problem is only with one bank, you could swap the sensor from one bank to the other, clear the code, and see if the code is followed to the other bank. That would tell you it is the sensor/heater itself that’s failed.
Check for outstanding technical service bulletins (TSB) for your vehicle, in some cases the PCM can be recalibrated to fix this (not a common fix though). TSBs could also call for replacement of the sensor.
When replacing oxygen / AF sensors, be sure to use a high quality ones. In many cases non-OEM sensors are of lesser quality and will not perform correctly. We strongly recommend you stick with OEM brand replacements.
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"Delete Error Code Permanently, Disable DTC Error Code Function for p2196 in the ECU"
In extreme cases, we even have the option to permanently remove the specific DTC p2196 and disable the function of the specific error code in the ECU. All other fault code functions will then continue to work to protect the engine. This is different from clearing an error code with a diagnostic device. We have the option to permanently remove the function of the specific error code, so that it never comes back. Also emergency running that occurs on the specific error code can be solved in most cases.
Of course we prefer to first try to solve the cause of the error code, but sometimes the only solution is to permanently disable the DTC function of p2196.
