Hi All,

This is my first post on this Camry Forum.....thanks for inviting me! I have a 2007 Toyota Camry CE (4 cyl) with 80K. I am the second owner and it was well maintained by an elderly woman.

A few weeks ago it popped a P2238 code so I went the logical route and bought an oxygen sensor. The first repair suggestion I saw pointed to Bank 1 / Sensor 1 which was easily accessible on the top of the engine. After a few days the same code went off again. Any suggestions on what to do next?

Some research suggest it's a faulty EFI Relay. Does anyone know the location and part number. I hate to throw parts at the car and was hoping you might provide some guidance!

Thanks in Advance!

Bob K
Hawthorne, New York

 

The EFI relay may be built into the circuit board.

What brand of sensor did you use?

 

Denso Part #234-9049

 

The relay is supposed to be in the same fuse/relay box as the EFI fuse.

See private message.

 

Hi,

After installing the new Denso #234-9049 the P2238 code went off again once and after resetting it hasn't gone off in the past 5 days. In addition I replaced the battery yesterday because it tested bad. Today the air conditioner cycles frequently and the engine runs rough. It actually stalled at idle for the first time. Is there a necessity to update/flash the ECM after replacing the battery.

I discussed the issue with a local mechanic who said to make sure I installed an air/fuel sensor and not an oxygen sensor because that could cause it to run rough. He said they look the same? When I researched the Denso part it is called both air/fuel sensor and oxygen sensor on Rockauto and Amazon. Could someone please help me out with the confusion? He suggested I install the old Oxygen Sensor back and see if the rough idle and cycling AC still exists.

When the first code appeared two weeks ago it ran fine but I needed the problem fixed so it passes inspection next week.

Thanks in advance!

Thanks,
Bob K

 

Bank 1 Sensor 1 is the first sensor on the exhaust system. This sensor is upstream of the converter.

An A/F operates over a narrower range then the O2 sensor and is more precious in its output signal. Car makers have an A/F sensor before the converter to measure air/fuel ratio for the computer to use to adjust the engines air/fuel ratio. The O2 sensor is after the converter and used solely to determine the condition of the converter. This sensor doesn't need to be precious.

In years past both sensors were typically O2 sensors before the A/F sensor came along.

The cars computer will run self checks on various systems using predetermined criteria. Sometimes this requires multiple car trips and driving at certain MPH with a certain throttle position, etc

If the battery is disconnected the computer will need to relearn the engines throttle position. The idle may be off until it does.

Your Denso part number checks out as Bank 1 Sensor 1 at various auto parts sites. Denso is a good brand as some brands will cause the check light to come on. See link below:

https://www.densoproducts.com/denso-...cal-afr-sensor

Might confirm this using the Oxygen Sensor Location Guide on the webpage.

Why is A/F and O2 interchanged, who knows as they are not the same thing.

The engine may run fine with a defective sensor or not. MPG may drop.

If you are going to have the car emission tested don't disconnect the battery anymore. When the battery is disconnected the computer self checks reset to zero. The emission center will be checking if all self checks are complete and "ready." From time to battery disconnect to this ready status for all checks can take days or longer as each check has its own test criteria.