Troubleshooting codes P0650, P0449...

[Firstymer]

Yesterday, I decided to take my 00' GP SE to AutoZone and the following codes were scanned P0650 and P0449. They printed out what the codes means, however, I need help troubleshooting the problems. Especially after experiencing the car stalling or shutting off on me on the road. I take it to AutoZone immediately. Can you anyone suggest any advices?

Car info:
00' GP SE
122550+ km

No tune-up since last May 07'

[BNaylor]

Which engine. 3.1L?

P0449 is Evaporative Emissions Control System Fuel Tank Vent Circuit Fault

P0650 is MIL Control Circuit Malfunction

MIL is Malfunction Indicator Lamp meaning the SES/CEL light circuits. Neither one should cause the car to stall or shut off.

[Firstymer]

Thanks for the reply, so If I can simply fix the problem w/ a Haynes or Clinton repair manual book, so I can easily fix the problem with the stallling or shutting off. So what is causing the car to shut off sometimes on the road.

I believe the engine size is standard with the GP SE v6 either 3.1L or 3.8L im not sure...

[BNaylor]

Originally Posted by Firstymer

I believe the engine size is standard with the GP SE v6 either 3.1L or 3.8L im not sure...

Check the 8th digit of the VIN number. From left to right.

VIN "J" = 3.1
VIN "K" = Normally Aspirated SII 3800
VIN "1" = Supercharged SII 3800

[Firstymer]

Ok, its VIN "J"...quick question, because of code malfunction
P0449 is Evaporative Emissions Control System Fuel Tank Vent Circuit Fault, would it cause the engine to have a rough/Erratic sound when either driving and/or stop?

[richtazz]

I doubt that code would cause stalling, unless the tank is developing such a negative pressure due to the bad vent valve that it's causing a "vapor lock" type issue (again, highly doubtful).

Have you noticed any coolant loss?

[BNaylor]

Originally Posted by richtazz

I doubt that code would cause stalling, unless the tank is developing such a negative pressure due to the bad vent valve that it's causing a "vapor lock" type issue (again, highly doubtful).

Although unlikely and doubtful it could be possible Rich but you never know. Since the evaporative emissions system uses engine vacuum which is negative vacuum. I recall people that had stalling issues with evaporative emissions problems but for example only - when gas cap was removed the stalling stopped. Thats the problem with vent circuit problems and he may need further diagnostics or even professional help since these issues can be complex.

But in the meantime the usual suspects come to mind. Ignition and fuel is what I would check first. Check fuel pressure to make sure the fuel filter, fuel pump, FPR, fuel supply are good and look into one of the crank sensors possibly being bad. There are two separate crank position sensors on the 3.1L engine.

[richtazz]

I was asking about coolant loss thinking that it's possible he has the infamous intake leak that the 3.1 is known for. This could cause low vacuum, that could also cause engine vacuum related codes to pop up. Chasing these evap/vent codes can be frustrating.

[Firstymer]

I have to remind you that some of these terms are foreign to me. However, I need actual photos to locate such items-two separate crank position sensors, ignition, etc. and procedure to take further actions to solve the problem. In addition, I can check if the coolant level has decrease otherwise please keep me posted because this problem becoming a headache!!

Originally Posted by BNaylor

Although unlikely and doubtful it could be possible Rich but you never know. Since the evaporative emissions system uses engine vacuum which is negative vacuum. I recall people that had stalling issues with evaporative emissions problems but for example only - when gas cap was removed the stalling stopped. Thats the problem with vent circuit problems and he may need further diagnostics or even professional help since these issues can be complex.

But in the meantime the usual suspects come to mind. Ignition and fuel is what I would check first. Check fuel pressure to make sure the fuel filter, fuel pump, FPR, fuel supply are good and look into one of the crank sensors possibly being bad. There are two separate crank position sensors on the 3.1L engine.

[BNaylor]

Photos? Not asking for much are you. It is up to the member weighing-in if they have any pics or tech procedures applicable to your engine and whether they have the time. Doing what was requested can be very tedious.

In the meantime, you can check fuel pressure DIY - (Do It Yourself) at the Schrader valve located at the rear fuel injector rail passenger side by the alternator and power steering pump. Use a standard auto fuel pressure tester. See pic below. Fuel pressure varies but look for something greater than 40 psi, preferably at least 48-55 psi.



As suggested monitor coolant level to help rule out possible flaky LIM gaskets which are a known issue on the 3.1L engine. An engine vacuum test may help. Always good to make sure engine vacuum ranges from 15 - 22 in-hg. You can use a standard 0-30 in hg auto vacuum tester connected at the lower intake manifold (LIM) vacuum ports.

On the crank sensors the main one is located behind the harmonic balancer located at the front crankshaft of the engine. The second 3X crank position sensor is harder to get to and located under the rear exhaust manifold on the engine block. You may need professional help to check and replace these items which could cause your symptoms (stalling). Do you ever get a SES/CEL light?

[Firstymer]

No, I never see any SES/CEL light comes on, however, I notice since I had the car the ABS light stays on when the car is turn on-drive.

[Firstymer]

I want to also info you richtazz and BNaylor that the car cranks right away when temperature outside is round 50 degrees and below. Also there's no noticable erractic rpms but white smoke out the exhaust. Also the car does cut off when the car is push to the max>such as If I was racing going up to 30-95mph on the streets or highway but once I come to a stop or slow down rapidly it cuts off!!

[Firstymer]

Well, I notice strong white smoke coming out of the exhaust and I also notice coolant loss in the rev. Any suggestions?

Originally Posted by BNaylor

Photos? Not asking for much are you. It is up to the member weighing-in if they have any pics or tech procedures applicable to your engine and whether they have the time. Doing what was requested can be very tedious.

In the meantime, you can check fuel pressure DIY - (Do It Yourself) at the Schrader valve located at the rear fuel injector rail passenger side by the alternator and power steering pump. Use a standard auto fuel pressure tester. See pic below. Fuel pressure varies but look for something greater than 40 psi, preferably at least 48-55 psi.



As suggested monitor coolant level to help rule out possible flaky LIM gaskets which are a known issue on the 3.1L engine. An engine vacuum test may help. Always good to make sure engine vacuum ranges from 15 - 22 in-hg. You can use a standard 0-30 in hg auto vacuum tester connected at the lower intake manifold (LIM) vacuum ports.

On the crank sensors the main one is located behind the harmonic balancer located at the front crankshaft of the engine. The second 3X crank position sensor is harder to get to and located under the rear exhaust manifold on the engine block. You may need professional help to check and replace these items which could cause your symptoms (stalling). Do you ever get a SES/CEL light?

[wlkjr]

My advice would be to get the intake gaskets replaced asap. You are risking losing the engine.

[Firstymer]

How? Can you explain? Once I get expert advice from the service maintenance dept. at Pontiac dealership in my town then I'll get back at you on what they suggest.