SaturnFans.com
what's new (beta) - classifieds - forums - photos


Go Back   SaturnFans.com Forums > Models > Saturn S-Series > S-Series Tech
Register FAQ Members List Groups Calendar Chat Room Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Display Modes
Old 07-02-2014, 06:56 PM   #1
wingsauce7
Member
wingsauce7 has a spectacular aura aboutwingsauce7 has a spectacular aura about
 
Join Date: May 2014
Location: Loveland, CO
Posts: 133

2001 SL1
2000 SL1
Default P401...again

So I know this is a problem with many threads. I have 326,000+ miles on a 2001 SL1. I have had this code for quite some time. I've cleaned the EGR valve and replaced with a U pull it model. I have zero engine problems with this code, yet it still comes back.

When I remove the valve and run the engine, I get good exhaust from the exhaust manifold port and get good vacuum on the intake manifold side. I'm pretty sure i don't have a clogging issue.

I'm starting to think a car with this many miles is just destined to have a code, but it irritates me nonetheless.

...
2001 SL1
5 Speed
390,000 miles!

REWARD EXCELLENCE!

Add to wingsauce7's Reputation
Rate the quality of this post and help wingsauce7 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
wingsauce7 is offline   Reply With Quote
SaturnFans.com Sponsored Links
Old 07-02-2014, 11:27 PM   #2
fdryer
Super Member
fdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond repute
 
fdryer's Avatar
 
Join Date: Jan 2006
Location: NYC
Posts: 40,235
 

2003 L-Series 3.0L Sedan
Default Re: P401...again

Well, here's the info to go by. Reprinted from the service manual. GM doesn't have to deal with any car beyond the factory warranty but will gladly entice "loyal" customers to removing and replacing anything until repairs are completed......on the customers dime$$$$$$$$$. There are many Saturns up there in mileage without error codes.

DTC P0401

The exhaust gas recirculation (EGR) valve consists of a pintle valve which moves by the use of an internal solenoid and an internal position sensor (potentiometer) used to determine pintle valve position. The powertrain control module (PCM) controls the solenoid by supplying it ignition voltage whenever exhaust gas needs to be recirculated into the intake manifold. The PCM monitors the EGR solenoid and position sensor circuit for correct voltage levels at certain times. The PCM also monitors the flow of exhaust gas through the EGR valve by using the manifold absolute pressure (MAP) sensor. During deceleration, the EGR valve is normally closed. However, the PCM will run a flow test by opening the EGR valve and monitoring the change in the MAP signal voltage. DTC P0401 sets when the change in the MAP signal voltage is below a certain threshold when the EGR valve is being commanded ON during the deceleration.

DTC Parameters

DTC P0401 will set if the PCM determines EGR flow to be restricted based on engine speed and barometric pressure using the MAP sensor when:
  • The engine speed is between 1250-2600 RPM.
  • The vehicle speed is greater than 56 km/h (35 mph).
  • The throttle position (TP) angle is 0 percent (vehicle in decel).
  • The engine coolant temperature (ECT) is greater than 70C (150F).
  • No cam, crankshaft position (CKP), ECT, EGR solenoid, 5-volt reference, idle air control (IAC), intake air temperature (IAT), MAP, misfire, PCM internal fault, TP or vehicle speed DTCs have been set.
DTC P0401 diagnostic runs once per ignition cycle for 1 second during deceleration once the above conditions have been met.

DTC P0401 is a type A DTC.

Diagnostic Aids

Verify the MAP sensor reads correctly at idle (between 1-1.5 volts). If the MAP sensor is skewed or faulty, DTC P0401 may set.

The most likely cause of this DTC is carbon buildup around the EGR valve or a blocked EGR passage.

Remove the EGR valve and check for a blocked passage and for carbon buildup around the EGR pintle valve. Clean or replace the EGR valve and/or clean EGR passage.
Attached Images
File Type: jpg egr valve.jpg (67.4 KB, 16 views)

REWARD EXCELLENCE!

Add to fdryer's Reputation
Rate the quality of this post and help fdryer reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
fdryer is offline   Reply With Quote
Old 07-02-2014, 11:40 PM   #3
OldNuc
Super Member
OldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond repute
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 64,431
 

1998 SC2
Default Re: P401...again

Take he MAP off and verify the port into the intake manifold is not blocked by the goo. Look at the MAP port and verify it is not plugged. Do not poke into the MAP.

Quote:
Originally Posted by wingsauce7 View Post
So I know this is a problem with many threads. I have 326,000+ miles on a 2001 SL1. I have had this code for quite some time. I've cleaned the EGR valve and replaced with a U pull it model. I have zero engine problems with this code, yet it still comes back.

When I remove the valve and run the engine, I get good exhaust from the exhaust manifold port and get good vacuum on the intake manifold side. I'm pretty sure i don't have a clogging issue.

I'm starting to think a car with this many miles is just destined to have a code, but it irritates me nonetheless.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 07-03-2014, 10:07 AM   #4
wingsauce7
Member
wingsauce7 has a spectacular aura aboutwingsauce7 has a spectacular aura about
 
Join Date: May 2014
Location: Loveland, CO
Posts: 133

2001 SL1
2000 SL1
Default Re: P401...again

Thanks guys. I'll check the MAP port tonight. I actually have a new sensor if needed also.

Didn't I also see someplace here some pin out locations and values for the EGR solenoid when moving the pintle? I guess it's possible the one from the J/Y could be faulty as well.

...
2001 SL1
5 Speed
390,000 miles!

REWARD EXCELLENCE!

Add to wingsauce7's Reputation
Rate the quality of this post and help wingsauce7 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
wingsauce7 is offline   Reply With Quote
Old 07-03-2014, 10:24 AM   #5
OldNuc
Super Member
OldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond repute
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 64,431
 

1998 SC2
Default Re: P401...again

See post #2 for the pin designations, right hand side.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 07-03-2014, 09:02 PM   #6
wingsauce7
Member
wingsauce7 has a spectacular aura aboutwingsauce7 has a spectacular aura about
 
Join Date: May 2014
Location: Loveland, CO
Posts: 133

2001 SL1
2000 SL1
Default Re: P401...again

Nothing really jumped out at me with the MAP sensor or port in the intake manifold. There was a little sludge in the intake manifold port, but nothing like a blockage. The sensor wasn't obstructed at all. I cleaned the port and cleared the code. I'll driver her on Independence Day.

...
2001 SL1
5 Speed
390,000 miles!

REWARD EXCELLENCE!

Add to wingsauce7's Reputation
Rate the quality of this post and help wingsauce7 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
wingsauce7 is offline   Reply With Quote
Old 07-03-2014, 09:06 PM   #7
wingsauce7
Member
wingsauce7 has a spectacular aura aboutwingsauce7 has a spectacular aura about
 
Join Date: May 2014
Location: Loveland, CO
Posts: 133

2001 SL1
2000 SL1
Default Re: P401...again

One other thing, If I want to completely rule out the EGR valve itself, can I fabricate a port-less gasket out of metal between the engine and the valve then drive the car for a couple days to see if the code comes back?

...
2001 SL1
5 Speed
390,000 miles!

REWARD EXCELLENCE!

Add to wingsauce7's Reputation
Rate the quality of this post and help wingsauce7 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
wingsauce7 is offline   Reply With Quote
Old 07-04-2014, 12:37 AM   #8
fdryer
Super Member
fdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond repute
 
fdryer's Avatar
 
Join Date: Jan 2006
Location: NYC
Posts: 40,235
 

2003 L-Series 3.0L Sedan
Default Re: P401...again

Not really because you haven't mentioned any engine problems. Most egr valve problems are caused by sticking pintle valves that let exhaust gases mix with fresh air at the wrong time causing hesitation, stumbling, balking, erratic idle and stalling. The error code definition is explaining how the map sensor is used with the egr valve feedback position sensor to determine valve operation. A mismatch can be map sensor, egr valve or wiring. Blocking off the ports underneath the egr valve won't do anything since this test is used to check for drivability issues as stated - not having drivability issues rules out one part of the egr valve but not another. What if the egr valve is dead or slow moving? Unless you can test pintle valve movement by applying power or measure position sensor output, you're left to either clean it or replace it, again. The used one has no guarantees so it may have failed. Some egr valves last forever while some fail prematurely. No rhyme or reason. You're also in high mileage territory where anything goes.

REWARD EXCELLENCE!

Add to fdryer's Reputation
Rate the quality of this post and help fdryer reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
fdryer is offline   Reply With Quote
Old 07-04-2014, 12:10 PM   #9
wingsauce7
Member
wingsauce7 has a spectacular aura aboutwingsauce7 has a spectacular aura about
 
Join Date: May 2014
Location: Loveland, CO
Posts: 133

2001 SL1
2000 SL1
Default Re: P401...again

Here a great resource for performing checks to your GM Electric EGR valve.

http://easyautodiagnostics.com/gm_eg...gr_valve_1.php

easyautodiagnostics.com/gm_egr_test/gm_egr_valve_1.php

...
2001 SL1
5 Speed
390,000 miles!

REWARD EXCELLENCE!

Add to wingsauce7's Reputation
Rate the quality of this post and help wingsauce7 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
wingsauce7 is offline   Reply With Quote
Old 07-07-2014, 09:45 AM   #10
wingsauce7
Member
wingsauce7 has a spectacular aura aboutwingsauce7 has a spectacular aura about
 
Join Date: May 2014
Location: Loveland, CO
Posts: 133

2001 SL1
2000 SL1
Default Re: P401...again

code set again. I'll take the bed of nails to the EGR wiring tonight..

...
2001 SL1
5 Speed
390,000 miles!

REWARD EXCELLENCE!

Add to wingsauce7's Reputation
Rate the quality of this post and help wingsauce7 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
wingsauce7 is offline   Reply With Quote
Old 07-13-2014, 02:49 PM   #11
wingsauce7
Member
wingsauce7 has a spectacular aura aboutwingsauce7 has a spectacular aura about
 
Join Date: May 2014
Location: Loveland, CO
Posts: 133

2001 SL1
2000 SL1
Default Re: P401...again

Quote:
Originally Posted by wingsauce7 View Post
Here a great resource for performing checks to your GM Electric EGR valve.

http://easyautodiagnostics.com/gm_eg...gr_valve_1.php

easyautodiagnostics.com/gm_egr_test/gm_egr_valve_1.php
So I did step 1 in the above link (verifying the EGR valve produces the correct voltage signal with key in run and engine off). I had 0.78 VDC which is in range

That took me to step 5 (verifying the EGR pintle position sensor in the EGR is working correctly). I had smooth increasing VDC pushing pintle in and smooth VDC coming back to the seated position.

Next, the TS guide took me to step 7, which is simply seeing how the engine runs without the EGR mounted. My engine runs smooth with the valve off which indicates a clogged passage in the intake's plenum.

Funny thing is, I have good air output at the exhaust side of the EGR mounting location and I have good vacuum on the intake side of the base (using a strip of paper verifying it was trying to suck into the intake side).

I'm guessing that even with clogged passages, you could still have good suction at the intake side of the EGR mounting location?

Next step in the TS guide says to remove the Intake Manifolds Plenum to physically remove blockage.

Exactly what is the plenum and how is it removed?

...
2001 SL1
5 Speed
390,000 miles!

REWARD EXCELLENCE!

Add to wingsauce7's Reputation
Rate the quality of this post and help wingsauce7 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
wingsauce7 is offline   Reply With Quote
Old 07-13-2014, 03:06 PM   #12
OldNuc
Super Member
OldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond repute
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 64,431
 

1998 SC2
Default Re: P401...again

In your case you clean it out with a piece of speedometer cable and carb cleaner.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 07-13-2014, 03:33 PM   #13
wingsauce7
Member
wingsauce7 has a spectacular aura aboutwingsauce7 has a spectacular aura about
 
Join Date: May 2014
Location: Loveland, CO
Posts: 133

2001 SL1
2000 SL1
Default Re: P401...again

Starting from the EGR base and moving into the IM?

...
2001 SL1
5 Speed
390,000 miles!

REWARD EXCELLENCE!

Add to wingsauce7's Reputation
Rate the quality of this post and help wingsauce7 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
wingsauce7 is offline   Reply With Quote
Old 07-13-2014, 05:48 PM   #14
OldNuc
Super Member
OldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond repute
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 64,431
 

1998 SC2
Default Re: P401...again

Yes. I believe there is a richpin06a video of doing this with a tie-wrap. Serious rodding with a tie-wrap will work also. I believe it is titled measuring the length of the EGR ports or something like that.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 07-13-2014, 06:38 PM   #15
wingsauce7
Member
wingsauce7 has a spectacular aura aboutwingsauce7 has a spectacular aura about
 
Join Date: May 2014
Location: Loveland, CO
Posts: 133

2001 SL1
2000 SL1
Default Re: P401...again

Couldn't find a video except one on a Honda which conveniently put a plate under the fuel that can be removed for access.

So are these passages similar to the fresh air ports on the exhaust side? Would there be one for each cylinder? If they're anything like the ones I cleared on my exhaust, I can't imagine being able to clear them with a wire or cable.

Thanks

...
2001 SL1
5 Speed
390,000 miles!

REWARD EXCELLENCE!

Add to wingsauce7's Reputation
Rate the quality of this post and help wingsauce7 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
wingsauce7 is offline   Reply With Quote
Old 07-13-2014, 06:52 PM   #16
fdryer
Super Member
fdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond repute
 
fdryer's Avatar
 
Join Date: Jan 2006
Location: NYC
Posts: 40,235
 

2003 L-Series 3.0L Sedan
Default Re: P401...again

Quote:
Originally Posted by wingsauce7 View Post
............My engine runs smooth with the valve off which indicates a clogged passage in the intake's plenum.

Funny thing is, I have good air output at the exhaust side of the EGR mounting location and I have good vacuum on the intake side of the base (using a strip of paper verifying it was trying to suck into the intake side).

I'm guessing that even with clogged passages, you could still have good suction at the intake side of the EGR mounting location?

Next step in the TS guide says to remove the Intake Manifolds Plenum to physically remove blockage.

Exactly what is the plenum and how is it removed?
If the engine didn't rev immediately to programmed rev limits (4000-4500 rpm) with the egr valve removed, there's a serious blockage of the intake port passage. The intake plenum is the intake manifold between throttle body and engine cylinder head, on the rear side of the engine.

REWARD EXCELLENCE!

Add to fdryer's Reputation
Rate the quality of this post and help fdryer reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
fdryer is offline   Reply With Quote
Old 07-13-2014, 07:45 PM   #17
wingsauce7
Member
wingsauce7 has a spectacular aura aboutwingsauce7 has a spectacular aura about
 
Join Date: May 2014
Location: Loveland, CO
Posts: 133

2001 SL1
2000 SL1
Default Re: P401...again

Quote:
Originally Posted by fdryer View Post
If the engine didn't rev immediately to programmed rev limits (4000-4500 rpm) with the egr valve removed, there's a serious blockage of the intake port passage. The intake plenum is the intake manifold between throttle body and engine cylinder head, on the rear side of the engine.
Yep, blocked. So does the intake manifold have to be unbolted and removed from the block to be effectively cleaned?

....and would the blockages be in the IM side or the engine side?

...
2001 SL1
5 Speed
390,000 miles!

Last edited by wingsauce7; 07-13-2014 at 07:51 PM..

REWARD EXCELLENCE!

Add to wingsauce7's Reputation
Rate the quality of this post and help wingsauce7 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
wingsauce7 is offline   Reply With Quote
Old 07-13-2014, 08:27 PM   #18
OldNuc
Super Member
OldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond reputeOldNuc has a reputation beyond repute
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 64,431
 

1998 SC2
Default Re: P401...again

Do not take off the intake as it will accomplish nothing. The blockage is up close to the intake. Have at it with a long tie-wrap. https://www.youtube.com/watch?v=dJ_TkgjIW8U

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 07-13-2014, 10:35 PM   #19
wingsauce7
Member
wingsauce7 has a spectacular aura aboutwingsauce7 has a spectacular aura about
 
Join Date: May 2014
Location: Loveland, CO
Posts: 133

2001 SL1
2000 SL1
Default Re: P401...again

This video shows the length of passage from the EGR back to the exhaust side. I thought my blockage was from the EGR to the intake?

...
2001 SL1
5 Speed
390,000 miles!

REWARD EXCELLENCE!

Add to wingsauce7's Reputation
Rate the quality of this post and help wingsauce7 reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
wingsauce7 is offline   Reply With Quote
Old 07-13-2014, 10:55 PM   #20
fdryer
Super Member
fdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond repute
 
fdryer's Avatar
 
Join Date: Jan 2006
Location: NYC
Posts: 40,235
 

2003 L-Series 3.0L Sedan
Default Re: P401...again

When the egr valve is removed to expose the two ports under it, the exhaust port blowing exhaust out is one thing, the intake port leading to the intake manifold is supposed to be free of carbon exhaust deposits. Any engine start up with the egr valve removed results in a large vacuum leak since the intake port is completely unblocked so the engine revs immediately to programmed rev limits to prevent runaway engine damage. If you didn't see or hear the engine rev to 4K rpm then the intake port is blocked, period.

Last edited by fdryer; 07-13-2014 at 11:03 PM..

REWARD EXCELLENCE!

Add to fdryer's Reputation
Rate the quality of this post and help fdryer reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
fdryer is offline   Reply With Quote
Reply



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

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Codes P401 and P405 - EGR ?? jchu210 S-Series Tech 5 09-19-2012 06:53 PM
P401 code will not go away Whiplash7x S-Series Tech 2 10-15-2010 06:31 PM


All times are GMT -5. The time now is 03:17 AM.

Advanced Forum Search | Advanced Photo Search


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
SaturnFans.com. The Saturn Enthusiasts Site.