Aleromod.com Aleromod.com

Go Back   Aleromod.com > Performance Related > LA1 3400 Specific

Reply
 
Thread Tools Search this Thread Display Modes
Old 12-05-2011, 07:57 PM   #1
wearetheromans85
GX Member
 
wearetheromans85's Avatar
 
Join Date: Nov 2008
Location: Houston, TX
Posts: 56
wearetheromans85 is on a distinguished road
P0446 Anyone dealt with this code before?

computer is throwing a p0446 and I'm kind of stumped on how to get rid of it. I've already replaced the vent valve. There's power at the connector to the valve. This code could also be pointing towards a leak or maybe a faulty ftp sensor. Just wondering if anyone else has had this code.
wearetheromans85 is offline   Reply With Quote
Old 12-05-2011, 07:59 PM   #2
wearetheromans85
GX Member
 
wearetheromans85's Avatar
 
Join Date: Nov 2008
Location: Houston, TX
Posts: 56
wearetheromans85 is on a distinguished road
I also hooked up the smoke machine at work and looked for leaks. The only place the smoke comes out is the vent valve when it's open.
wearetheromans85 is offline   Reply With Quote
Old 12-05-2011, 09:39 PM   #3
zzyzzx
GLS member
 
zzyzzx's Avatar
 
Join Date: Mar 2008
Location: Baltimore, MD USA
Posts: 5,529
zzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond repute
Yes, but on a Toyota Camry where this is an exceptionally common problem. Besides all the possible vacuum line problems, there is something like 4-5 valves in the whole system, and even something like a bad fuel filler tube can cause a problem (although that's not your case). I'd also check the fuel cap.

This one can be a real PIA to fix and normally takes several attempts unless you are like most auto mechanics who would indiscriminately replace everything it could possibly be (the Toyota TSB suggests this).
zzyzzx is offline   Reply With Quote
Old 12-05-2011, 09:46 PM   #4
wearetheromans85
GX Member
 
wearetheromans85's Avatar
 
Join Date: Nov 2008
Location: Houston, TX
Posts: 56
wearetheromans85 is on a distinguished road
gas cap was first thing i checked. hooked it up to the inspection machine and did integrity test. You are right about it being a PITA.
wearetheromans85 is offline   Reply With Quote
Old 12-06-2011, 12:21 AM   #5
MMGT1
GLS member
 
MMGT1's Avatar
 
Join Date: Jun 2011
Location: Canada
Posts: 1,319
MMGT1 has a reputation beyond reputeMMGT1 has a reputation beyond reputeMMGT1 has a reputation beyond reputeMMGT1 has a reputation beyond reputeMMGT1 has a reputation beyond reputeMMGT1 has a reputation beyond reputeMMGT1 has a reputation beyond reputeMMGT1 has a reputation beyond reputeMMGT1 has a reputation beyond reputeMMGT1 has a reputation beyond reputeMMGT1 has a reputation beyond repute
A code P0446 could mean one or more of the following has happened:

Faulty vent valve
Open, short or excessive resistance on Vent valve control circuit
Blockage of vent valve
Bad PCM
Possible SolutionsWith a P0446 OBD-II trouble code, here are some things to try:

Replace Vent valve
Repair open, short, or resistance problem in control circuit
Repair open, or short, or resistance problem in power circuit
Replace PCM
__________________
A SS looks like it could kick your ass if it wanted to, but a WS6 looks like it's coming over to do it
MMGT1 is offline   Reply With Quote
Old 12-06-2011, 07:09 AM   #6
a.graham52
Premier V.I.P. Member
 
a.graham52's Avatar
 
Join Date: Dec 2009
Location: New Hampshire
Posts: 1,979
a.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond repute
Send a message via MSN to a.graham52
Circuit Description

The evaporative system (EVAP) includes the following components:

• The fuel tank

• The EVAP vent solenoid

• Fuel tank pressure sensor

• The fuel pipes and hoses

• The fuel vapor lines

• The fuel cap

• The EVAP canister

• The purge lines

• The EVAP canister purge solenoid valve

• The EVAP service port

The EVAP system is checked by applying vacuum to the EVAP system and by monitoring for a vacuum decay. The Powertrain Control Module (PCM) monitors the vacuum level through the fuel tank pressure sensor signal. At an appropriate time, the EVAP canister purge solenoid valve and the EVAP vent solenoid are turned ON, allowing the engine to draw a small vacuum on the entire evaporative emission system. After the desired vacuum level has been achieved, the EVAP canister purge solenoid valve is turned OFF, sealing the system.

A restricted or blocked EVAP canister vent path is detected by drawing a vacuum on the EVAP system, turning OFF the EVAP vent solenoid and the EVAP canister purge solenoid valve, with the EVAP vent solenoid open and the EVAP purge pulse width modulation (PWM) 0 percent, and monitoring the fuel tank vacuum sensor signal. With the EVAP vent solenoid open, any vacuum in the system should decrease quickly unless the vent path is blocked. A blockage can be caused by the following conditions:

• A malfunctioning EVAP vent solenoid, stuck closed

• The vent hose for the following conditions:

- Plugs

- Kinks

- Pinches

• A shorted EVAP vent solenoid driver circuit

• A plugged evaporative canister

If any of these conditions are present, DTC P0446 will set.

Conditions for Running the DTC (With EGR)

• DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0452, P0453, P0502, P0503, P0601, P0602, P1133 and P1621 are not set.

• The BARO is greater than 75 kPa.

• The intake air temperature is between 5°C and 29°C (41°F and 84°F) at engine start up.

• The engine coolant temperature is between 5°C and 29°C (41°F and 84°F) at engine start up.

• The Intake Air Temperature is not more than 1°C (2°F) greater than the Engine Coolant Temperature at start up.

• The Engine Coolant Temperature is not more than 7°C (12°F) greater than the Intake Air Temperature at start up.

• The fuel tank level is between 26 percent and 74 percent.

• The TP sensor is between 7 percent and 35 percent.

• The EVAP solenoid is at 40 percent PWM.

Conditions for Running the DTC (without EGR)

• DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0452, P0453, P0502, P0503, P0601, P0602, P1621 and P1133 are not set.

• The BARO is greater than 75 kPa.

• The intake air temperature is between 5°C and 29°C (41°F and 84°F) at engine start up.

• The engine coolant temperature is between 5°C and 29°C (41°F and 84°F) at engine start up.

• The Intake Air Temperature is not more than 1°C (2°F) greater than the Engine Coolant Temperature at start up.

• The Engine Coolant Temperature is not more than 7°C (12°F) greater than the Intake Air Temperature at start up.

• The fuel tank level is between 26 percent and 74 percent.

• The TP sensor is between 7 percent and 35 percent.

• The EVAP solenoid is at 40 percent PWM.

Conditions for Setting the DTC

The EVAP system is unable to release vacuum during the diagnostic test.

Action Taken When the DTC Sets

• The Malfunction Indicator Lamp (MIL) will illuminate.

• The PCM will record the operating conditions at the time that the diagnostic fails. The Freeze Frame and Failure Records buffers will store this information.

• A history DTC stores.

Conditions for Clearing the MIL/DTC

• The MIL will turn OFF after 3 consecutive ignition cycles in which the diagnostic runs a pass.

• A history DTC will clear after 40 consecutive warm up cycles without a malfunction.

• A scan tool can clear the DTCs.

Diagnostic Aids

Although this DTC is considered a type A diagnostic (refer to Serial Data Communications ), this DTC acts like a type B diagnostic under certain conditions. Whenever this diagnostic reports that the system has passed, or if the battery is disconnected, the diagnostic must fail twice before setting a DTC. The initial failure does not report to the diagnostic executive or display on a scan tool. A passing system always reports to the diagnostic executive immediately.

If a DTC P0460, P0461, P0462 or P0463 is set along with an EVAP System DTC, the EVAP DTC cannot be considered valid until you repair and clear DTC P0460, P0461, P0462 and P0463.

Check the following components for the indicated conditions:

• A poor electrical connection at the PCM. Inspect the harness connectors for the following conditions:

- Backed out terminals

- Improper mating

- Broken locks

- Improperly formed connectors

- Damaged terminals

- A poor terminal to wire connection

• A damaged wiring harness. Inspect the wiring harness to the following components for an intermittent open or short circuit:

- EVAP vent solenoid

- EVAP canister purge solenoid valve

- Fuel tank pressure sensor

• Verify the following conditions are not present in the vent hose between the canister and the EVAP vent solenoid is not restricted:

- Kinked

- Pinched

- Plugged

- Restrictions

• Refer to Evaporative Emission System Cleaning for further procedure.

Test Description

The number(s) below refer(s) to the step number(s) on the Diagnostic Table.

1 The Powertrain OBD System Check prompts you to complete some of the basic checks and to store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data captured when the malfunction occurred. The scan tool stores this data for later reference.


3 If a vent solenoid electrical malfunction is present, the purge system will not operate correctly. Repairing the electrical malfunction will very likely correct the condition that set DTC P0446.


4 This step checks the fuel tank pressure sensor at the ambient pressure.


6 This step verifies that the fuel tank pressure sensor accurately reacts to the EVAP system pressure changes.


8 This step checks for a blocked EVAP canister.


12 This step duplicates the Powertrain On-Board Diagnostic test.



Id love to post the flowchart for diagnostics but it would reqire a lot more space and cuting and pasting wont work for it. ill see what i can do.
__________________
The dumbass that shows up randomly 10 years after selling the car.
a.graham52 is offline   Reply With Quote
Old 12-06-2011, 09:59 AM   #7
zzyzzx
GLS member
 
zzyzzx's Avatar
 
Join Date: Mar 2008
Location: Baltimore, MD USA
Posts: 5,529
zzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond reputezzyzzx has a reputation beyond repute
a.graham52's email describes exactly how to fix it and why it is such a PIA to fix. I really hate this code. That and if it works anything like the previously mentioned Toyota (and it probably does) if you let it go you'll get more related codes, like the gas cap code, and P0440, P0441, P0442, etc. even though you might only have one problem.

I really hate this code. On the Toyota I replaced a really hard to get to valve wedged under the car near the gas tank (very difficult to remove a rusted out philips head screw in a bad location). Of course I put in a stainless steel hex head bolt when I put in the new valve. The code came back around 4-6 weeks later, then I coated the gas cap gasket with a light coat of oil and reset the codes, and in the 2-3 months since then it hasn't come back, but I would not be surprised if it did. Toyota wants you to replace the valve that I did, plus an OEM only charcoal canister assembly that contains 2 valves on it, plus all the vacuum hoses in the canister area (they seem to think that the if the vacuum hoses aren't cracked, they therefore must be clogged). All of this is in a really poor location too.

The rusted in philips head screw that requires and offset screwdriver to remove, if you can remove it at all makes this design particularly crappy as well. All they needed to do was to spend a couple of cents more for a stainless steel hex head screw like I did and it would have made the replacement job a whole lot easier since I could have gotten a wrench on it (no space for ratchet).
zzyzzx is offline   Reply With Quote
Old 12-06-2011, 04:39 PM   #8
a.graham52
Premier V.I.P. Member
 
a.graham52's Avatar
 
Join Date: Dec 2009
Location: New Hampshire
Posts: 1,979
a.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond reputea.graham52 has a reputation beyond repute
Send a message via MSN to a.graham52
so i worked on a 99 k1500 today that had a p0446 code. heres how i diagnosed it:
  • need to use a scantool capable of watching fuel tank pressure AND be able to munipulate the EVAP system (command purge on etc)
  • i commanded the purge valve on 100% with the vent valve open. this is alowing then engine to apply vaccume to the evap canister and related hoses as well as the fuel tank. and yes you do wnat the vent valve open during this.
  • while doing that above step i watched fuel tank pressure. went down to about -7.5 H20 and stayed there. acceptable vaccume though the system is -5H20 or less.
  • i unplugged the vent valve from the canister (removing some restriction to the system) and now im looking at -6H2o
  • still not happy with the resuls i unplugged the canister from the fuel tank and watched fuel tank pressure. took about 15secounds to to 0H2o. pressure should have equalized MUCH quicker then that.
  • next step to try and find out where the restiction was was to take the other end of the hose (that goes from the fuel tank to charcoal canister) off of the fuel tank. (this is after i hooked everything back up to put vaccume back in the fuel tank)
  • once unhooked from the tank pressure still dropped slow. so now i know there is a restriction in the fuel tank and the tnak has to come out.

this isnt the best detailed instructions but im just trying to give you guys some insight. pretty much theres a blockage in the evap system and the goal is to elimate peice by peice untill i find where the blockage is located.
__________________
The dumbass that shows up randomly 10 years after selling the car.
a.graham52 is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 10:39 AM.


Powered by vBulletin Version 3.6.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.