Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 7 of 7 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter · #1 ·
Hi everybody, I will try to tell my story short. My car is 2007 Trailblazer with one code: P0411.

What I want: the voltage range reading of the secondary air injection system flow sensor, the range that is good for the PCM. Also the PID for that sensor on the Torque APP.

What I have and did so far:
  • I don’t have a pro scanner, all what I have is a Bluetooth ELM327 device and the Torque APP on my phone.
  • I check there is no water in the fan or the hoses.
  • In order to test the system I added two wires to the fan relay and the solenoid relay, so I can make them run as I wand by grounding those wires. Photo #1.
  • I made a T-harness for the solenoid/sensor so I can measure the volt using a multimeter. Photo #2.
  • Start the car and let it warm up, the volt reading when the fan and the solenoid not active was 2.67 volt. Photo #3.
  • I only turn the fan ON and the reading was 3.56 volt Photo #4, then turn both ON and the reading was 3.42 volt Photo #5.
  • Also while both ON I have a look at the O2 sensor reading, photo #6, see how the reading was normal then start to drop all the way down, then after I turn both OFF the reading start to rise up. photo #6. It back to normal after that, I didn’t take a photo for that.
  • As a test I turn only the fan ON and the O2 reading didn’t change, stead normal, I didn’t take a photo for that.
  • I removed the hose end that goes to the solenoid and turn ON the fan then sensed the air by hand it was strong. Then I removed the solenoid and did the same test to see if the solenoid was working. Fan ON with the solenoid ON and OFF, the air still strong when ON and when OFF there was no air at all, so I can say that the solenoid is working fine.
  • One note, while the system was installed there was a small air leakage where the hose mount to the solenoid. Dose it should be good seal or that normal?
By the look at the O2 reading while the system in working I assume that it do its job, but the PCM do not like the sensor reading. I want to fool the PCM by designing a circuit (by the way I am an electronics engineer) that convert the volt reading to the right one for the PCM. That why I need the correct volt reading.
Wow that was short!!!!!!!!!!
Thanks
Audio equipment Bottle Drink Automotive lighting Liquid
Automotive tire Automotive wheel system Gas Auto part Wrist
Product Measuring instrument Bicycle accessory Technology Service
Gadget Bicycle accessory Medical equipment Measuring instrument Machine
Bicycle accessory Font Machine Service Technology
Green Product Font Technology Electronic device
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #3 ·
Thank you TJBaker. I already know this, it have only the pressure values and to use them I need a pro scanner or the PID for this reading on the Toruqe APP. but with volt reading it will be so easier for me to go on with my plane to fix it.
 

·
Registered
2002 chevy trailblazer_lt
Joined
·
1,459 Posts
I normally figure the equation myself. The PID number would need to be located then you need to identify the sensor as 2 bar, 3 bar etc. Look around online for datasheets, they usually give the details needed for you to write the equation. Pretty much all the [GM] extended PID in Torque Pro were figured out by end/user enthusiasts as GM does not release such proprietary information.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #5 · (Edited)
TJBaker, as you said the [GM] extended PID in Toruqe Pro were figured out by users. This is why I asked here, may be some one figure this one. I wonder if the Tech2 scan tool can relive this kind of info?
One more thing, with the code P0411 what is not correct exactly? is the reading too high or too low?
 

·
Registered
2002 chevy trailblazer_lt
Joined
·
1,459 Posts
TJBaker, as you said the [GM] extended PID in Toruqe Pro were figured out by users. This is why I asked here, may be some one figure this one. I wonder if the Tech2 scan tool can relive this kind of info?
One more thing, with the code P0411 what is not correct exactly? is the reading too high or too low?
They don't seem to say if it is high or low, just that the error is over 6 kPa.

I looked over your voltage readings and at a guess I am thinking you may have some blockage or the solenoid valve is not fully opening. The reason I think this is there is not much of a voltage drop between where you have fan on and solenoid valve closed (phase 2 test, 3.56 vdc) vs fan on and solenoid valve open (phase 1 test, 3.42 vdc).

Look at the picture I posted previously and compare the phase 2 test with the phase 1 test. The expected rise in kPa for the phase 2 test is a little more that double the expected rise for the phase 1 test. Every pressure sensor I have dealt with is linear. Now look at your voltage rises in your tests of the system. Your phase 2 test has a voltage rise of 0.89 volts and your phase 1 test has a voltage rise of 0.75 volts. I would be looking for a phase 1 voltage rise of less that half of the phase 2 voltage rise.

I do have a Tech 2 but no 2007 ECM to have a look at. My 2002 has no SAIS, those didn't start until 2004. Yes, the Tech 2 does read out this sensor in both volts and psi and for the 07 also reads the error in kPa I believe.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #7 ·
since I want to make my story short, I didn't mention that I found that there was a carbon build up in the area shown by red rectangles. this car have a high mileage on it: near 230000 (this photo is not for my car)
Helmet Automotive tire Font Machine tool Auto part


I clean as much I can. I use a break cleaner on the valve but not for the engage side. I afraid that some of the cleaner will get inside the cylinders. so you may be right about the blockage. but since the O2 reading drops to almost zero when test the fan and the valve, it seems not bad.

I found this PDF file on line but I didn't try to add any PID on my APP yet.
There are more files may be so useful, have a look at them, the link is:

I start working on a circuit to convert the volt reading to some thing like what you suggest about the rise and drop. I will tell you the results when done.

For the Tech 2. I am sure it can do that, what I meant is finding the PIDs and the related info from the Tech 2.
 

Attachments

1 - 7 of 7 Posts
Top