2004 Trailblazer LT 4.2L L6

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Revision as of 09:41, 4 November 2014 by Webdawg (talk | contribs) (Brakes Soft, Pedal Travel)

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Sensor Locations

Secondary Air Injection

  • for now:
  1. wait for your car to be "cold" or 4 hours. Disconnect the hose from check valve (located passenger side--the transmission dip stick is attached to the bolts that hold it to the block). Start the truck, you should hear a nasty sound for about 30 seconds to a minute. If you don't its your check valve.
  2. If it is your check valve, you can try to clean it. Get some throttle body cleaner, remove the check valve spray thouroughly (I did it a couple of times to get all the carbon and rust out) and let dry reinstall and follow above instructions. If no go replace check valve
  1. wait for your car to be "cold" or 4 hours. remove the fattest hose from the underside of air intake hose (I think thats where it is, I have a CAI so Its hard to know where it is exactly OEM) and from the check valve. Have someone else start the truck. Feel the hoses, you should feel sucking and blowing (I can't remember which is supposed to blow / suck) If you don't feel anything then its the pump (maybe -- read further)
  2. check fuses there are about 3 in the manual listed for air pump (if bad fuse replace and retest, make sure to check the fuses after to make sure that the pump isnt blowing fuses)
  3. Locate the air pump its driver side mid car just behind the cross member for the frame. There are two wiring harnesess one that goes into the relay (grey box) and one that has two fat wires (thats the power plug for the pump.) disconnect that one, wait for cold start and start truck while having a multimeter attached set on DC mode. If you get a reading of 0 then replace the relay. if you get power 12-15 volts replace the motor.
  4. If both the check valve and the pump are testing out ok it could be a clogged hose.

Camshaft Position Actuator Solenoid Cleaning

Putting an AMP in

Throttle Body

Blower Motor Resistor

Recalibrate Vent Actuators

  • Disconnect the Battery for a while
  • Make sure all vent stuff is off
  • Turn car on, let sit for 60 seconds at least

or

36 HVAC B
39 HVAC 1
44 HVAC

Start car, leave on for one min.

Clean Sending Unit

Use alot of this at once: Chevron 65740 Techron Concentrate

Replace Dash Stepper Motors

This is where I got mine:

They work great

Replace Thermostat and Temp Sensor

I do not think I should have done the temp sensor...what a pita. Some people say go through the wheel well. I did not and it seems like it would have been easier through the wheel well. But then some people say it is harder. You will have to find those instructions.


Doing by taking the alternator off:

Fuel Filter

Brakes Soft, Pedal Travel

Sounds funny but, I had new brake fluid put in, did some other stuff. I had to engage the ABS on a dirt/sand road and the pedal firmed right up.

  • Some Issue: I wouldnt ever push the brake fluid back thru the master cylinder. It will mess up the ABS. I dont know the exact reason but every vehicle that I've seen with that done the ABS will throw a code and act funny. Best thing to do it crack the bleeder when re-seating the pistons back. Other than that, I dont have a fix for ya.

Quote:

After a LOT of researching, I decided that the ABS system needed to be cycled. Not necessarily bled, as there should be no air in the system, but at least cycled in order to undo whatever I did to it when I back-pressed the caliper pistons.

After more digging, I discovered I had two choices: I could take it to a dealer and have them "bleed" the ABS according to the shop manual's process using their Scan Tool. Our local dealers want a hundred bucks just to hook the Scan Tool up!

Other choice was to force the ABS to cycle itself, and hope that would reset it. It was worth a try, and if it didn't work there was still the dealer.

Following the instructions I found, I took the truck out to a loose-gravel road (just a quarter mile from home, out here in the countryside). Starting cautiously, I got up to a blistering 10 mph and stomped the brake pedal hard as I could. With all my strength, I was able to get just a half-dozen barks out of the ABS. But that was enough. The second time, the brakes applied a little harder and the ABS barked a little more. Each time, I could go a little faster and hit the brakes a little harder.

A couple dozen repeats of this, speed up to 50 mph near the end, was probably over-kill. But that fixed it!

I gave it one more bleed to be sure, and there was no air in the system. So after I made the mistake of pressing the fluid backwards through the system, I just needed to "reset" the ABS by forcing it to cycle itself. (I don't think the new master cylinder was a bad idea, either.)

So thanks, Donut Slayer! Your comment got me on the right track. And I'll never back-push the fluid in an ABS system again. Open the bleeder and press it out into a container.

End Quote

Basically same as above: