2004 - Trailblazer - 4.2/I6 - Oxygen Sensor/Catalytic Converter Testing/Type/Wiring

webdawg

Well-Known Member
Hello,

If anyone has been following my other thread (http://gmtnation.com/forums/threads/2004-tb-i6-4wd-manifold-red-hot.14795/) you know I am about to replace my manifold and catalytic converter.

What I would like to do is test the o2 sensors and wiring. I also would like to check the new catalytic converter. I was reading here: http://www.autodiagnosticsandpublishing.com/feature/o2-sensor-testing.html

That site says: Stating around model year 1999, a new type of converter came on the market, called “Low Oxygen Storage Converter” or LOC. With an LOC, the pre and post O2 sensors cycle at the same rate. These converters are tested by measuring the lag-time between the two signals. A further development of this system is that the post converter signal is also used for A/F correction, but to a less extent.

One of the questions I have is what type of converter do I have on my 2004 TB. Am I going to be inspecting the phase or? What are the graphs supposed to look like?

I have more questions but I need to do more research first.
 
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webdawg

Well-Known Member
Allright so right now I want to test all the wires to see if they are good to the two o2 sensors. Here is what I am pulling from the wire diagram:

PCM is on (UPPER LEFT SIDE OF ENGINE) (Connector C2)

HEATED OXYGEN SENSOR 1 (ON EXHAUST MANIFOLD)
(E) - DK GREEN WIRE -> HO2S HTR LO B1 S1 (PIN 31 ON PCM)
(D) - PINK WIRE -> 02 FUSE 29 (10) (C1) (UNDER HOOD FUSE BLOCK)(HOT IN RUN AND START)
(A) - TAN WIRE -> HO2S LO SIG B1 SI (PIN 32 ON PCM)
(B) - PPL/WHT -> HO2 HI SIG B1 S1 (PIN 23 ON PCM)

HEATED OXYGEN SENSOR 2 (DOWNSTREAM OF CATALYTIC CONVERTER)
(C) - BLACK/WHITE -> HO2S HTR LO B1 S2 (PIN 30 ON PCM)
(D) - PINK -> 02 FUSE 29 (10) (C2) (UNDER HOOD FUSE BLOCK)(HOT IN RUN AND START)
(B) - PPL/WHT -> HO2 HI SIG B1 S2 (PIN 26 ON PCM)
(A) - TAN/WHT -> HO2S LO SIG B1 S2 (PIN 18 ON PCM)



Pulling the PCM pin out from here: http://forums.trailvoy.com/showthread.php?t=88193

It looks like I can test these wires using that PCM out.

It looks like you identify the PCM connector by color:

C1 (BLU) = blue... C2 (DK GRY) = grey... C3 (NAT) = natural

Pictures where I pulled info:

img049.jpg img050.jpg img051.jpg img052.jpg
 

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webdawg

Well-Known Member
I was not. I may just skip this but if I still have overheating issues, I am going to check. I also figured because I did all the work looking it up, I should post it.
 

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