1999 Lexus ES 300 computer engine issue -P1153

On Mon, 09 Jul 2007 21:39:49 -0500, Ray O wrote:

> "nospam" <nospam.DeleteThis@sbcglobal.net> wrote in message
> news:qwgki.8721$Rw1.2742@newssvr25.news.prodigy.net...
>> My neighbor did a test on my Lexus due to a check engine light on that
>> just came on. It came back with a P1153 code as being an issue. He was
>> real busy and would have to look more into it later. I was wondering if
>> someone else had this issue and what I should be checking for
>> specifically?
>>
>> What I do know is it is referring to:
>> P1153 Air/Fuel Ratio Sensor Circuit Response Malfunction (Bank 2 Sensor 1)
>>
>> He was thinking it also had something to do with ...
>>
>> "the 1153 is probably related to the P1150 O2 sensors."
>>
>>
>>
>> Any additional feedback would be appreciated.
>>
>> Bryan
>>
> IIRC, some vehicles with California emissions use air/fuel ratio sensors
> instead of O2 sensors and have a different diagnostic trouble code (DTC)
> than O2 sensors. I believe that your car is one of those vehicles, and the
> procedure for testing them is pretty much the same as checking an O2 sensor.
> When the engine and sensor are fully warmed up, look for a varying voltage
> signal from the sensor. If voltage does not vary or is non-existent, the
> sensor is probably bad.

A/F sensors are 'biased' and quicker, but you need a scan tool to check
them (Data List function). If the wires are continuous and not shorted to
+ or - or each other, then all that's left is ECU or sensor. CHECK
(CONT/SHORT) WIRES WITH COMPONENTS DISCONNECTED AND USE A METER.

It's probably the sensor....
 >> Stay informed about: 1999 Lexus ES 300 computer engine issue -P1153 

Maybe take a look to see if it's really a intake gasket. Remove both the PCV valve and the breather hose and plug both fittings at the Valve Covers with your fingers. If you feel a vacuum, you have a intake leak.

If you can read scan tool information, there will most likely be a LTFT issue. If LTFT is okay, it's a matter of looking at the O2 sensor and verifying that it is indeed cycling slowly. Swapping it to the other bank would verify a defective sensor as the code (or more properly- the O2 waveform/scan tool data shows the slow sensor is now on the other bank).

A vacuum leak that isn't the lower intake should not cause a single bank code, but should be a problem that effects both banks. Also, beware of using a http://www.lxpartsconnection.com/lexusaftermarketparts.html (Lexus aftermarket parts) of an intake, because they are more prone to lower intake leaks. A lower intake leak can cause a single bank problem. An intake leak is pretty common. Good luck!!!
 >> Stay informed about: 1999 Lexus ES 300 computer engine issue -P1153