rattle noise when in drive?

[SamBO]

hey whats up guys!!i have a 2004 z71 tahoe with about 148,xxx miles on odometer. Ok, it starts fine no problem but occasionally the check engine light comes on only whens its 32 degrees or lower outside temp. got it check and and the code was for an o2 sensor I have not got it changed as of yet. so heres the real ?? tahoe starts fine but when i start driving theres a low rattling noise so what I'm wondering is if it could be something with the catalytic converter or something to do with the Transmission or torque converter?? trans fluids check out fine. engine oil fine.
Or any ideas on what i should check
thanks for any feed back

 

[MO Viet Vet]

:welcome: to the forum.

Get used to this next part. I don't want to know what the code is about, I want the code number. It does us no good with general info like that. There are different breakdowns of O2 sensor codes and your info does not help. You have 4 sensors.

Your rattle may in fact be from the cat convertor broke loose inside and therefore the efficiency of that cat is effected and therefore the code but help us help you by starting with better details.

 

[SamBO]

ok will due. the code was p0134

 

[MO Viet Vet]

Ok, here goes....

This code refers to the front oxygen sensor on Bank 1. Basically the oxygen sensor is inactive. Here's why:

The powertrain control module (PCM) provides a baseline voltage of about 450 mV on the oxygen sensor signal circuit. When cold, the PCM detects the internal resistance of the sensor is high. As the sensor warms up the resistance is lowered and it starts producing voltage based on the oxygen content in the exhaust. When the PCM determines that the time it took for the sensor to warm up is greater than one minute or that the voltage is inactive (not reading outside 391-491 mV it views the sensor as inactive or open and sets the P0134 code.

Potential Symptoms

One or more of the following may occur:
•Check engine light illumination
•Poorly running/engine missing
•Blowing black smoke
•Poor fuel economy
•Dying, stuttering

Causes

A code P0134 may mean that one or more of the following has happened:
•Bad O2 (oxygen) sensor
•Bad heater circuit in the O2 sensor
•Wiring or connector to the sensor frayed / broken
•Blown heater circuit fuse
•Holes in the exhaust system
•PCM failure

Possible Solutions

The most common fix is to replace the oxygen sensor. But that doesn't rule out the possibility of:
•Rusted exhaust pipe
•Inspect wiring & connector(s) for problems
•Excessive amperage blowing heater fuse (still requires replacement of sensor but also replacement of blown fuse)
•Replace PCM (only as last resort after all other possibilities are covered.



So, as long as is the only code you got, it is the front sensor on the drivers side cat convertor. Read thru the possible problems but if in fact you have a cat conv on the drivers side that is broke loose inside then that is the place to start. Crawl under and with engine off tap on the cat conv with a rubber mallet or your palm and see if the inside rattles. Check both cats while there. If is rattling then get it replaced and at least do the sensors on the drivers side. Both of them. If you got plenty of money and are keeping the rig for sure then do all 4 sensors. That way they are the same age. That is my recommendation but others here may have other suggestions. Use the one that you like best. Heck, if you are keeping the rig for sure and have the money, do both cats. They are all the same age anyways, I assume.

 

[rockenthebowtie]

You can get a mallet and hit the catalytic converters see if the rattle your hearing in drive is the same from when you hit the converters, if you go with factory cats they only come in a set, dont recommend aftermarket converters