Help with CEL please. - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
Problems and Service Talk about any mechanical problems you are having

Closed Thread
 
LinkBack Thread Tools Display Modes
post #1 of 23 (permalink) Old 02-15-2014, 04:49 PM Thread Starter
Prospect
 
Join Date: Feb 2014
Posts: 23
Help with CEL please.

I have a 2005 Chevy Cobalt LS 2.2L. I regularly get a P0420 code. I have also gotten the following code a few times with the P0420(although not every time):

P0106: Manifold Absolute Pressure (MAP) Sensor Performance - PCM

Also, 2 times in the last 6 months, I have gotten the following code(resulting in "reduced engine power"):

P01681: Control Module Throttle Position (TP) System Performance - PCM

Here are 3 freeze frames(after clearing the CEL and waiting for it to come back on):

Freeze Frame 1:
DTCFRZF() P0420
FUELSYS1() OL
FUELSYS2() --
LOAD_PCT(%) 14.9
ECT(。C) 92
SHRTFT1(%) 0.0
LONGFT1(%) 8.6
MAP(kPa) 37.0
RPM(rpm) 787
VSS(km/h) 0
SPARKADV(。) -1.0
IAT(。C) 11
MAF(g/s) 3.77
TP(%) 24.7
RUNTM(sec) 1331
EVAP_PCT(%) 0.0
FLI(%) 56.9
BARO(kPa) 103
VPWR(V) 13.025
LOAD_ABS(%) 22.0
EQ_RAT () 0.916
TP_R(%) 11.8
AAT(。C) 4
TP_B(%) 24.3
APP_D(%) 17.3
APP_E(%) 9.0
TAC_PCT(%) 15.7

Freeze Frame 2:
DTCFRZF() P0420
FUELSYS1() OL
FUELSYS2() --
LOAD_PCT(%) 14.9
ECT(。C) 91
SHRTFT1(%) 0.0
LONGFT1(%) 7.8
MAP(kPa) 40.0
RPM(rpm) 703
VSS(km/h) 0
SPARKADV(。) -4.0
IAT(。C) 0
MAF(g/s) 3.70
TP(%) 24.7
RUNTM(sec) 1393
EVAP_PCT(%) 0.0
FLI(%) 52.9
BARO(kPa) 101
VPWR(V) 14.599
LOAD_ABS(%) 23.5
EQ_RAT () 0.916
TP_R(%) 11.4
AAT(。C) -1
TP_B(%) 23.9
APP_D(%) 17.3
APP_E(%) 9.0
TAC_PCT(%) 15.3

Freeze Frame 3:
DTCFRZF() P0420
FUELSYS1() OL
FUELSYS2() --
LOAD_PCT(%) 13.3
ECT(。C) 90
SHRTFT1(%) 0.0
LONGFT1(%) 7.0
MAP(kPa) 37.0
RPM(rpm) 700
VSS(km/h) 0
SPARKADV(。) -3.5
IAT(。C) 4
MAF(g/s) 3.29
TP(%) 23.5
RUNTM(sec) 986
EVAP_PCT(%) 0.0
FLI(%) 71.4
BARO(kPa) 99
VPWR(V) 15.183
LOAD_ABS(%) 21.2
EQ_RAT () 0.916
TP_R(%) 10.6
AAT(。C) -3
TP_B(%) 22.7
APP_D(%) 17.3
APP_E(%) 9.4
TAC_PCT(%) 13.7

I am not sure if the P0420 is indeed a problem with the cat, or if it's somehow related to the other problems. I did not start routinely getting the P0420 code until AFTER the very first time I got the P1681. Thanks so much in advance guys.

Last edited by ChevyTerry; 02-15-2014 at 05:30 PM.
ChevyTerry is offline  
Sponsored Links
Advertisement
 
post #2 of 23 (permalink) Old 02-15-2014, 05:23 PM
Super Moderator
YourCobalt.com Premium Member


 
Coby7's Avatar
 
Join Date: Oct 2011
Location: Magnetic Hill, New-Brunswick
Posts: 11,820
Garage
First off P0242 is not a valid code for a 2005 Cobalt wether boosted or not. What reader are you using?

P0420 can be set by a sudden lack of air intake, for instance hitting a puddle of water and sucking some water into the filter box when temperatures are below freezing. This will cause the water to freeze almost instantly causing air passage restriction. This will force PCM to cut fuel and cause exhaust rich and lean codes. P0420 means cat is inneficient. This might also trick PCM into setting odd codes unrelated. Your 3 freeze frames are all normal. Check your air filter next time for ice or water. Now if you live in southern California disregard all of the above.

Every minute spent angry is a happy minute lost for ever and ever!!!
Drives 2016 Cocoa Buick Encore 1.4L Turbo auto KL4CJDSB2GB652675
Drives 2016 Sunset Orange Trax LT1 1.4L Turbo auto 3GNCJPSB8GL142716

Never drive faster than your guardian angel can fly

Last edited by Coby7; 02-15-2014 at 05:27 PM.
Coby7 is offline  
post #3 of 23 (permalink) Old 02-15-2014, 05:34 PM Thread Starter
Prospect
 
Join Date: Feb 2014
Posts: 23
Quote:
Originally Posted by Coby7 View Post
First off P0242 is not a valid code for a 2005 Cobalt wether boosted or not. What reader are you using?

P0420 can be set by a sudden lack of air intake, for instance hitting a puddle of water and sucking some water into the filter box when temperatures are below freezing. This will cause the water to freeze almost instantly causing air passage restriction. This will force PCM to cut fuel and cause exhaust rich and lean codes. P0420 means cat is inneficient. This might also trick PCM into setting odd codes unrelated. Your 3 freeze frames are all normal. Check your air filter next time for ice or water. Now if you live in southern California disregard all of the above.
I had not gotten my own code reader until recently. Before that I just stopped at AutoZone, but the guys at my local AutoZone are douche bags. I'm convinced P0242 did not actually occur. I have however confirmed the P1681 with my own code reader, the Autel AL519, which I bought not too long ago. I've removed the reference to P0242 from my OP.
ChevyTerry is offline  
 
post #4 of 23 (permalink) Old 02-15-2014, 05:45 PM
Super Moderator
YourCobalt.com Premium Member


 
Coby7's Avatar
 
Join Date: Oct 2011
Location: Magnetic Hill, New-Brunswick
Posts: 11,820
Garage
When was the last time you checked or changed your air filter? Make sure rodents haven't built a nest under the filter.

Every minute spent angry is a happy minute lost for ever and ever!!!
Drives 2016 Cocoa Buick Encore 1.4L Turbo auto KL4CJDSB2GB652675
Drives 2016 Sunset Orange Trax LT1 1.4L Turbo auto 3GNCJPSB8GL142716

Never drive faster than your guardian angel can fly
Coby7 is offline  
post #5 of 23 (permalink) Old 02-15-2014, 05:53 PM Thread Starter
Prospect
 
Join Date: Feb 2014
Posts: 23
Quote:
Originally Posted by Coby7 View Post
When was the last time you checked or changed your air filter? Make sure rodents haven't built a nest under the filter.
Last time it was checked was at Valvoline when I got my last oil change. It was clean.

These P0420s came out of no where. Here I was, had the car 4 years, cars running great, get the P1681, get a few P0106s and start routinely getting the P0420. 6 months goes by, then another P1681 pops up, which was about 2 weeks ago. Now back to the P0420s.
ChevyTerry is offline  
post #6 of 23 (permalink) Old 02-15-2014, 05:56 PM
Super Moderator
YourCobalt.com Premium Member


 
Coby7's Avatar
 
Join Date: Oct 2011
Location: Magnetic Hill, New-Brunswick
Posts: 11,820
Garage
Where do you live? any road salts applied? Maybe you just need to remove connectors on PCM, spray some cleaner and re-install.

Every minute spent angry is a happy minute lost for ever and ever!!!
Drives 2016 Cocoa Buick Encore 1.4L Turbo auto KL4CJDSB2GB652675
Drives 2016 Sunset Orange Trax LT1 1.4L Turbo auto 3GNCJPSB8GL142716

Never drive faster than your guardian angel can fly
Coby7 is offline  
post #7 of 23 (permalink) Old 02-15-2014, 06:04 PM
Forum Regular
 
Join Date: Jan 2014
Posts: 58
diagnostics for p1681, say to replace the ecm
short4stuff is offline  
post #8 of 23 (permalink) Old 02-15-2014, 06:07 PM Thread Starter
Prospect
 
Join Date: Feb 2014
Posts: 23
Quote:
Originally Posted by Coby7 View Post
Where do you live? any road salts applied? Maybe you just need to remove connectors on PCM, spray some cleaner and re-install.
I live in southern Indiana. I don't know if they use road salt around here, but this started last summer, so I'm fairly certain that wouldn't be the problem.

Something just tells me that there's something going on with either the MAP sensor or TPS(which is built into the throttle body) causing a rich condition.

I'm not completely ruling out a bad cat, but I think it would help to know what the typical fuel trim of these cars are. The highest fuel trim from the freeze frames is 8.6, which isn't horrible, but not exactly the best either.
ChevyTerry is offline  
post #9 of 23 (permalink) Old 02-15-2014, 06:12 PM
Forum Regular
 
Join Date: Jan 2014
Posts: 58
Does an 8.6 fuel trim not actual mean the engine is running lean. The ecm is trying to add 8.6% fuel... If the trim was -8.6% it would be trying to pull fuel.
short4stuff is offline  
post #10 of 23 (permalink) Old 02-15-2014, 06:20 PM Thread Starter
Prospect
 
Join Date: Feb 2014
Posts: 23
Quote:
Originally Posted by short4stuff View Post
Does an 8.6 fuel trim not actual mean the engine is running lean. The ecm is trying to add 8.6% fuel... If the trim was -8.6% it would be trying to pull fuel.
Hmmmmmmmmm, maybe you're right. Shows you how much I know about cars lol. I always thought it was the difference between short term vs long term. Someone educate me lol.
ChevyTerry is offline  
Sponsored Links
Advertisement
 
Closed Thread

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome