I’m Juliette and I had a 2006 Chevrolet Silverado 1500 4.8L extended cab purchased for me. I love my truck but there are a few issues.

My first being that the check engine light comes on when I try to pass someone or going over tall bridges. But it comes on after I let off the gas once I’ve topped the bridge. It doesn’t seem to have enough power to keep it up to speed going over the bridge. 2 codes come up P0455 and P0332 for knock sensor and EVAP system large leak. When pumping gas it continuously clicks the pump off. And something is draining my battery. Other than that it runs great!

But my most perplexing issue is with the AC. When I start my truck the AC will freeze you out idling. It only blows on setting 3 and not at all for the Defroster, but for one day it worked on 1,2,3 & 5. When I’m going down the road it doesn’t stay cold and the clutch keeps stopping. If I pull over and tap the clutch it comes back on. But not for long for me. I’ve read possible problems till I’m blue in the face. I don’t have a lot of money to spend on maybe’s and I don’t know what to start with. Please someone help a girl out! I have the knock sensors with connectors in my cart on Amazon along with a vapor canister purge valve solenoid but I haven’t purchased yet because I’m unsure that’s what I need.

UPDATE: the compressor clutch stopped working altogether. It now does nothing when I tap on it.
Also on the obdii it shows catalysts, O2 HO2 & EVAP not ready.

 

First a couple of necessary questions.

One. What OBDII codes are present? Please list them all.

Two. Do you own a Digital Multi-Meter (DMM or DVM)?

Three. Do you have a set of HVAC gauges or access to to a set? (I mean real set and not the gauge that is attached to a can of refrigerant.)

Four. Do you notice a gasoline odor when you are away from the gas pump?

Awaiting your answers.

 

OBDll codes P0332 P0455
Two: DMM yes
Three: no gauges
Four: No gasoline odor

 

Thanks for the information.

The P0332 is indicating that there is a problem with the Bank 2 (the one closest to the firewall) Knock Sensor Circuit. It could be a bad knock sensor, corroded electrical connection at the knock sensor, the engine running excessively lean due to a large vacuum leak, etc.)

The P0455 is letting you know that there is a large vacuum leak in the EVAP system.

Now, neither DTC is telling you that there is a defective part, so until you get these diagnosed, do not purchase any parts!!!!! If you do, you could be wasting money.

The AC problem we will leave for latter.

Here are a couple of webpages I would like you to read to help you understand what is going on and how to diagnose the problem(s):

https://www.700r4transmissionhq.com/...evy-silverado/

https://easyautodiagnostics.com/gm/4...e-definition-1

The first thing you should notice is that the large vacuum leak could also be the cause of the P0332 DTC. So, the first thing you need to do is to visually inspect the black polymer hoses that go to and connect the EVAP components to one another (the EVAP vent valve to the charcoal canister, the EVAP purge valve to the charcoal canister, the charcoal canister to the fuel tank, etc.) and the individual EVAP system components themselves. Look for cracked housings, unplugged electrical connectors, broken wires. Also check your gas cap to make sure that it;s seal is not cut or missing any pieces.

Now the other thing you will want to check are the EVAP purge and vent valves. You want to make sure that there is 12 VDC to them and that when they are not energized, the solenoid is in the closed position and not allowing air to flow through them. The EVAP purge valve will be located behind the throttle body and under the plastic engine cover. The EVAP vent valve will be located underneath the truck and be somewhere between the charcoal canister and the fuel tank. I'm attaching a pdf of a tech bulletin that has some pictures that will help and it also provides the part number for the updated vent valve, filter, and relocation kit (GM part number 19152349 or Standard Motor Parts CVS34).

Now after you find and correct the large EVAP system/vacuum leak, clear the codes from the OBDII system and see if the P0332 code reappears. If it does then go ahead and purse the knock sensor problem.

Now, because of the problems with counterfeit and cheap crappy parts on Amazon, you would be much better off to purchase your replacement parts from rockauto.com. Stick with brands like ACDelco, GM Genuine, Delphi, Standard Motor Products, Gates, Fel-Pro, etc. Stay away from the low cost "economy" or value parts because they will be low end part of suspicious quality (even if the come with a lifetime warranty - the company might not be around next week or it will have a zillion reasons to not warrant their part).

As far as the AC system goes, once you take care of the problem(s) causing the P0455 and P0332 DTCs, let me know and we can then delve into getting your AC to work once again.

Good Luck!

 

I think the reason the gas pump keeps clicking off is you need to change out the evap charcoal canister or clean it. But since you will have it off just get a new one. Low circuit could be your battery is going bad or is bad and check your alternator to see if it's working properly.

 

Skeeda is correct about the battery. You should get the battery load tested where the battery (after being fully charged) is put under a significant load (like 200 amps) and the battery voltage is monitored. If the battery voltage drops below something like 10.6 volts DC, then the battery is bad. Also, the alternator needs to be checked to make sure that it is putting out a proper charging voltage, AND that the AC ripple voltage is below 50 - 100 milli-volts AC. The lower the AC ripple voltage, the better, and the better for the battery as excessive AC voltage will kill a battery in short order.

 

EVAP system large leak? could be difference between fuel pumped, fuel used, fuel returned

insure when you press the gas you dont' have fuel spraying out. an easy way to get this is "whoever installed the fuel filter didn't tighten it enough"

 

one more item. GROSS LEAK may need extended diagnosis. but it means what it said. it's not a gas gap theres "allot of mishap going on with the fuel" (or wiring to the pump?) if that comes on.

if that's the original fuel pump REPLACE IT. they go bad they are a "wear part / consumable".

a gross leak on some cars can be leaky seal in the fuel pump (it pumps but the fuel doesn't register going to/back from engine)

an easy and inexpensive possible gross leak could be fuel pressure regulator leaking (would cause fuel pump to be always running to maintain pressure, thus throw a code for gross leak).