New owner of 2004 Aveo issues check engine light came on.

[thehunterooo]

I was saying that in general

I thought it may just need a coil pack or a tune up as well

[Ratchet104]

i wasnt reading the codes, i was looking at it seems the car is running, as he was asking about putting off the repair.

it wouldnt run if all the valves need replaced. so checking that with a compression test.

i would like to read the tsb though.

Ask and ye shall receive:

#05-06-01-030D: 1.6L L91 Intermittent Misfire During Deceleration or Steady State Highway Driving After Cold Start with DTCs P0300, P0700, P1781 and/or U0401 Set (Replace Valves and Valve Stem Seals) - (Sep 12, 2007)

Subject:1.6L L91 Intermittent Misfire During Deceleration or Steady State Highway Driving After Cold Start with DTCs P0300, P0700, P1781 and/or U0401 Set (Replace Valves and Valve Stem Seals)
Models:2004-2007 Chevrolet Aveo

2005-2007 Pontiac Wave (Canada Only)

with Eco-Tec II 1.6L Four Cylinder Engine (VIN 6 - RPO L91)

Built Prior to VIN Breakpoint 7B797231

This bulletin is being revised to add a VIN Breakpoint to the Models and update the Warranty Information. Please discard Corporate Bulletin Number 05-06-01-030C (Section 06 - Engine).
Condition

Some customers may comment on an engine misfire on rare occasions. Typically, misfires related to this valve sealing concern will be very intermittent. The intermittent misfires may or may not be felt by the driver and they will normally occur during engine warm up, deceleration, highway driving, wide open throttle acceleration, and/or uphill driving.
Additionally, DTCs P0300, P0700, and/or P1781 (2004 models)/U0401 (2005 models) may be set. If a brief engine misfire occurs, it is possible that a P1781 or U0401 DTC may set without the presence of a DTC P0300.
Cause

The engine misfire may be experienced due to a valve sealing concern.
Correction

If this concern is experienced, perform the appropriate SI diagnostics. If the SI diagnostics do not isolate a cause for the concern and the last 8 digits of the VIN are:

Important: On vehicles built prior to VIN breakpoint 5B406012, check GMVIS to see if the intake valves have already been replaced with the current P/N. If the intake valves have already been replaced, replace only the exhaust valves and valve seals.
• PRIOR to 5B406012, replace all 8 exhaust valves, all 8 intake valves, and all 16 valve seals. Refer to Cylinder Head Disassemble and Cylinder Head Assemble procedures in SI.

• AFTER and INCLUDING 5B406012, replace all 8 exhaust valves and all 16 valve seals. Refer to Cylinder Head Disassemble and Cylinder Head Assemble procedures in SI.

Parts Information

Part Number
Description
96440081
Valve, Intake
96830500
Valve, Exhaust
96840122
Seal, Valve Stem Oil
Warranty Information

For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
J0529 (2004-2006 model years)
Valve - Replace
Use Published Labor Operation Time
J0528 (2007 model year)





After reading this I realize it's for the wave, not the aveo...Still pretty good information

[petrified.rabbit]

that sounds like an oil in the cylinder issue from ripping "frozen" valve stem seals.

[viper34787]

ok i took it to aamco and they said that the p1781 that came back is a miscomunication of the ecm. they said i should replace ecm and then they can diagnose why the misfire is happening. couple of questions i know i have to have a gm dealer program the new ecm. but can i do the learn procedures without a obd2 scanner? and can it damage the car if i wait to do this? he said for aamco to do this it would be 650. but i saw on rockauto a new one cost 232 so give or take for shipping brings it to 250 at highest. i called chevrolet dealer and they said just to program it cost 99.00. so thats roughly 349 right there. what do you guys think. my wife thinks i should have chevy dealer to a new diagnostic on it and they would charge me 100.00 but thats applied to bill. so i am confused. also if the ecm is bad doesnt that mean car wouldnt run?

[petrified.rabbit]

if you buy an ecm, i'm not sure it would need programmed, but the sensor parameters might need set.

but how did they determine ecm? because the tcm is "requesting" a signal? check wiring?

might be a sensor issue.

[viper34787]

there words to me were miscomunication error. he said at aamco in clermont,fl to just buy a new ecm. but im afraid that if i do what if i end up in same spot if it is a simple wire harness issue. also this car was previously in an accident could that of damaged ecm?

[thehunterooo]

I would take it over to the chevy dealer on 50 (right before you get to 27) they are a really good dealer, if anything I would go there and have them look at it as well if you can not figure it out.

[Ratchet104]

If Aamco misdiagnoses it, they may just say oh well...If chevy misdiagnoses it, they'll fix it til it's right. Do it right and take it to a chevy dealer

[petrified.rabbit]

i have to say in this case, i would take it to chevy.

ecu could be bad, but it would still run yes. it is just a computer, it could work but not "print", or "go online".. in this case he signal isnt going to the trans, it seems. but that does not mean its not the coil pack or something also associated with another misfire issue.

ex:

if you have an issue and the computer doesnt know _____, because of that issue, it cannot forward that info to the tcm. hence the code.

[viper34787]

cool guys tomorrow im taking it to that chevy dealer in the morning. I figure while they diagnose it i can check out a new aveo or a dream of a corvette.lol. but seriously my dad when he left the family he left some auto stuff and one was a dvd set called alldata i found, its a version 10.10 but it has my car. so i checked and now i am scared of what repair bill could be. i have a max of 900 budget.