Error codes P0141 and P0420

[bnichols19]

Car keeps dying while driving doesn't matter if I'm running 75 on interstate or stopped in a driveway. It died when it chooses too, and starts the same. Sometimes it will crank and start right back up other times it will crank until I run the battery dead and have to get a jump.
I no nothing about cars and need help. please and thank you

 

[Rainman21]

How many miles is on it? Sounds like it could be a bad crank position sensor. The codes you listed are related to the downstream O2 sensor, which just detects the exhaust after it has passed through the catalytic convertor, I have never seen a bad downstream oxygen sensor cause a 3800 to quit running.

 

[DrivenDaily]

First off, welcome to here...

Second, most of us tend not to treat you differently due to your gender. Telling us you are not all that savvy lets us know that we just need to spend a little extra effort to explain things instead of assuming that you are familiar with things.

How many miles are on your car?

How often is maintenance performed? Who does it?

How many keys are on your keyring? If there are a lot, it could be acting like a slide-hammer over every bump. That will eventually damage the locking part (the tumbler) and possibly make it easier for it to rotate when it shouldn't, which would turn the engine off.

When it cranks but won't start, turn the key off, open the door, then turn the key to ON (but not Start) and listen for a click and a gentle "whirr" sound. That should be the fuel pump. If you don't hear it, try asking a friend to turn theirs to ON while you listen for it. Then you'll be more aware of what you're listening for. Also, while your car is acting like it should, start listening for the pump before each time you start it so you will have it in your memory for those times it doesn't start.

If the pump does not whirr, then it could be a fuse that is intermittently making/breaking contact (from burned or corroded terminals), a bad relay (which actually provides the power to the fuel pump), or a fuel pump that works only sometimes. It could also be damaged or chafed wiring or a plug connector for the fuel pump.

 

[bnichols19]

First off, welcome to here...

Second, most of us tend not to treat you differently due to your gender. Telling us you are not all that savvy lets us know that we just need to spend a little extra effort to explain things instead of assuming that you are familiar with things.

How many miles are on your car?

How often is maintenance performed? Who does it?

How many keys are on your keyring? If there are a lot, it could be acting like a slide-hammer over every bump. That will eventually damage the locking part (the tumbler) and possibly make it easier for it to rotate when it shouldn't, which would turn the engine off.

When it cranks but won't start, turn the key off, open the door, then turn the key to ON (but not Start) and listen for a click and a gentle "whirr" sound. That should be the fuel pump. If you don't hear it, try asking a friend to turn theirs to ON while you listen for it. Then you'll be more aware of what you're listening for. Also, while your car is acting like it should, start listening for the pump before each time you start it so you will have it in your memory for those times it doesn't start.

If the pump does not whirr, then it could be a fuse that is intermittently making/breaking contact (from burned or corroded terminals), a bad relay (which actually provides the power to the fuel pump), or a fuel pump that works only sometimes. It could also be damaged or chafed wiring or a plug connector for the fuel pump.

It has 146,409 miles on it the oil and things have always been maintained by my husband and done so every 4000 to 5000 miles. We recently replaced the fuel pump around 6 months ago. And this stalling out and dying around 2 months ago. My husband was thinking maybe the erg valve or the send unit on the fuel pump? He wanted me to ask your opinions about that possibility.

 

[bnichols19]

How many miles is on it? Sounds like it could be a bad crank position sensor. The codes you listed are related to the downstream O2 sensor, which just detects the exhaust after it has passed through the catalytic convertor, I have never seen a bad downstream oxygen sensor cause a 3800 to quit running.

It has 146,409 miles on it the oil and things have always been maintained by my husband and done so every 4000 to 5000 miles. We recently replaced the fuel pump around 6 months ago. And this stalling out and dying around 2 months ago. My husband was thinking maybe the erg valve or the send unit on the fuel pump? He wanted me to ask your opinions about that possibility.

 

[RD_Atlanta]

Here is something quick, easy & 'free' that your husband could try. Tug each wire (one at a time) on the ICM connector while the car is idling to see if one has poor connection and causes the engine to die.

Attachments​

• 
  ICM connector wires

 

[DrivenDaily]

@bnichols19

It has 146,409 miles on it the oil and things have always been maintained by my husband and done so every 4000 to 5000 miles. We recently replaced the fuel pump around 6 months ago. And this stalling out and dying around 2 months ago. My husband was thinking maybe the erg valve or the send unit on the fuel pump? He wanted me to ask your opinions about that possibility.

It has 146,409 miles on it the oil and things have always been maintained by my husband and done so every 4000 to 5000 miles. We recently replaced the fuel pump around 6 months ago. And this stalling out and dying around 2 months ago. My husband was thinking maybe the erg valve or the send unit on the fuel pump? He wanted me to ask your opinions about that possibility.

Above you see what appear to be duplicated replies. Actually, they are replies to your responses to me and then @Rainman21.

When you reply the same to different ones, you can always just reply to one and mention the other using the @ symbol (without a space). This way, you're not repeating yourself. This way, you're not repeating yourself. LOL. Don't worry, it takes time to learn how to use forums.

And if you want to include multiple people in your reply, just start a new line and click the "Reply" icon in their post, such as I've done here:

Here is something quick, easy & 'free' that your husband could try. Tug each wire (one at a time) on the ICM connector while the car is idling to see if one has poor connection and causes the engine to die.

Attachments​

• 
  ICM connector wires

That is a great idea!

 

[Homer Jay]

Could be a faulty MAF sensor, which is a common issue.
Next time it stalls, disconnect. If that helps, replace with a OE equivalent (Hitachi)

 

[bnichols19]

@bnichols19


Above you see what appear to be duplicated replies. Actually, they are replies to your responses to me and then @Rainman21.

When you reply the same to different ones, you can always just reply to one and mention the other using the @ symbol (without a space). This way, you're not repeating yourself. This way, you're not repeating yourself. LOL. Don't worry, it takes time to learn how to use forums.

And if you want to include multiple people in your reply, just start a new line and click the "Reply" icon in their post, such as I've done here:


That is a great idea!

I will let him know. Thank you to everyone for the kindness and ideas. Hoping something works out. I'll let everyone know if something solves the problem.

 

[bnichols19]

It has 146,409 miles on it the oil and things have always been maintained by my husband and done so every 4000 to 5000 miles. We recently replaced the fuel pump around 6 months ago. And this stalling out and dying around 2 months ago. My husband was thinking maybe the erg valve or the send unit on the fuel pump? He wanted me to ask your opinions about that possibility.

So my husband crawled up under the car and found that the wiring on the down stream O² sensor are missing completely as though someone cut them off would or could that make the car shut down? he then realized it's not the downstream sensor because it's on the catalytic converter itself. What is it?

 

[ulycyc]

That's the downstream O2 sensor. If the wires are missing/broken it will not cause the car to stall. It will set codes, effect gas mileage and emissions and may run rough at times. As said earlier check the MAF sensor, that will cause stalling/cutting out

 

[DrivenDaily]

So my husband crawled up under the car and found that the wiring on the down stream O² sensor are missing completely as though someone cut them off would or could that make the car shut down?View attachment 49631 he then realized it's not the downstream sensor because it's on the catalytic converter itself. What is it?

That cat looks not too good. Is that oil all over it, and the O2 sensor? If so, find the source of that leak and fix it fast!

 

[weilandjason]

Consider "ignition control module" and coil packs, very common problem with 3.8 v6. Try to use AC Delco parts, yes expensive, but the others are even more expensive in time, sweat and tears.

 

[02LTD2.0]

The downstream O2 sensor only monitors the condition of the Catalytic Converter. It has nothing to do with driveability. From that picture it looks like the O2 sensor is not sitting right. It's supposed to be perpendicular to the pipe that is after the Cat. It looks like a universal Cat was welded in. You have other things that are causing your problems.
How long have you owned this vehicle and do you know ANY of the service history?

 

[Buick City Bert]

When it will not start, determine if it is one of 2 conditions:

1) No fuel, check the fuel rail on top of the engine, trace it back from the injectors if necessary, there is a Schrader valve (like a tire valve) with a plastic cap on it, take a rag and a small screw driver, place the rag to intercept any fuel and gently push the valve in so that the pressurized (60 PSI) fuel is caught in the rag. If it does not come hissing out, you have a fuel delivery issue, think maybe intermittent bad connection to the pump. Personally I had a bad connector in the tank on the pump / sender unit one time. Check the connectors under hood and in the trunk first.

2) No spark, do this only if there is good fuel pressure, remove a spark plug wire, put a snug fitting screw driver or other steel round stock in the terminal boot and place the shank near (~1/8") a good ground, head bolt, spark plug, bracket, etc. While a helper turns the key to start monitor the gap for a spark.

One of these 2 conditions exists, No fuel, or no spark.

This will tell you which way to pursue a solution, intermittent issues are the worst, but often indicate loose connections.

A scan tool that will let you monitor, or initiate the sensors and servos (ie fuel pump) is a great help on OBDII cars.

 

[bnichols19]

Could be a faulty MAF sensor, which is a common issue.
Next time it stalls, disconnect. If that helps, replace with a OE equivalent (Hitach

Turns out it was the wiring on the crankshaft position sensor were loose, the husband replaced the sensor. Car is doing fine now. Thanks for all your suggestions and help. Truly.

 

[DrivenDaily]

Turns out it was the wiring on the crankshaft position sensor were loose, the husband replaced the sensor. Car is doing fine now. Thanks for all your suggestions and help. Truly.

Thanks for coming back and sharing the solution. It helps us fee like maybe we helped a bit, and it could easily help the next person.