[Jaison]

My Deville just recently went over 100,000 miles and now the "service engine soon" light comes on. Not only that, but the car started like stalling anytime I accelerate from a complete stop. Then the "service engine light" starts blinking. ( Keep in mind I'm not mashing it). I took it to the shop and got the following codes:
Po141-o2 sensor bank 1
Po154-o2 sensor bank 2
po155-heated o2 sensor bank 2
po3000-random misfire
po507-Idle speed high

I got the spark plug replaced, but I didn't get the car scanned again yet. Do the o2 sensors need to be replaced? Or is something causing them to get a bad reading? Where are the fuses for the o2 sensors located? Is all of this related?

 

[jimsbox]

Sounds like you may have CCCCC (Classic case of constipated catalytic converter). A bad cat won't exhaust sufficiently and becomes more obvious at higher throttle settings, ie may idle ok but may load up when you give it gas. I know the PCM compares the downstream O2 sensor to the up streams but don't know what code it would throw. Have you used any kind of solvent around the throttle body? If it contained silicone it will ruin your O2 sensors. You may also need to clean your throttle body using O2 sensor safe throttle body cleaner.

These are thoughts I would have but you may want to post more complete descriptions on the DTCs (codes), hopefully Ranger or Sub will respond, they have forgotten more than I will ever know.

 

[Jaison]

Sounds like you may have CCCCC (Classic case of constipated catalytic converter). A bad cat won't exhaust sufficiently and becomes more obvious at higher throttle settings, ie may idle ok but may load up when you give it gas. I know the PCM compares the downstream O2 sensor to the up streams but don't know what code it would throw. Have you used any kind of solvent around the throttle body? If it contained silicone it will ruin your O2 sensors. You may also need to clean your throttle body using O2 sensor safe throttle body cleaner.

These are thoughts I would have but you may want to post more complete descriptions on the DTCs (codes), hopefully Ranger or Sub will respond, they have forgotten more than I will ever know.

Thx for the quik response. They put some type fuel system cleaner in there not sure about the brand or whether it contained silicone or not. I know that it was pretty high stuff at 160 a bottle (dealership). I was told that would remove any water, deposits, ect from my fuel system. Here are more descriptive descriptions of my codes:
"P0141 - Heated Oxygen Sensor (HO2S) Heater Performance Bank 1 Sensor 2"
P0154 - Heated Oxygen Sensor (HO2S) Circuit Insufficient Activity Bank 2 Sensor 1

P0155 - Heated Oxygen Sensor (HO2S) Heater Performance Bank 2 Sensor 1

P0507 - Idle Speed High
PO3000- Random Misfire

Could a clogged catalytic converter cause the o2 sensors to go bad?

 

[jimsbox]

No, cat can't damage the sensors that I am aware of but the computer compares the up stream O2 sensors to the down stream sensor to determine the efficiency (whether it is producing too much back pressure) of the cat. The one thing that will surely kill an O2 sensor is the use of non sensor safe chemicals that can get into the exhaust system. That being said, did they out the chemical in before or after you started getting the O2 sensor codes? If after it was not the problem and if it was a dealer I doubt they would introduce an inappropriate chemical cleaner. Two of the codes ihdicate a problem with the heater portion of the sensors. The heaters are there for cold start up to decrease emissions until it warms up. As I understand it the sensors don't need to be heated once the exhaust has heated them. Do you have a factory (not Clymer or Haynes) service manual? You can subscribe on line to Alldata for an online searchable version or get a set from Helms or ebay. They have trouble shooting procedures for the DTCs, right now I don't have time but maybe later I can see what it suggests in my 00 Deville manuals. It sounds like the heateer circuits are compromised but I doubt both sensors and/or both cables are bad. I would look at the fuses under the hood (passenger side fender well in front of the coolant surge tank and see if there are any fuses or relays associated with the sensors there. I will be working on my car this evening and I will check as well.

I also was thinking about this a little more and it seems that if the heater circuits are the real problem, then once the car warms up if you clear the codes through the DIC the car may run fine until you shut it off again and let it cool off. The instructions for getting the codes and clearing them sould be in a sticky post at the top of this forum page.

I sent a private message to Submariner409 asking him to look at your thread, he is the most knowlegable person I know of on Cadillacs in general and is well versed in things automotive in general.

Keep us posted.

 

[Jaison]

Unfortunately I currently do not own a service manual. Initially I received the following codes when I took it to the shop:
"P0141 - Heated Oxygen Sensor (HO2S) Heater Performance Bank 1 Sensor 2"
P0154 - Heated Oxygen Sensor (HO2S) Circuit Insufficient Activity Bank 2 Sensor 1

P0155 - Heated Oxygen Sensor (HO2S) Heater Performance Bank 2 Sensor 1

P0507 - Idle Speed High
PO3000- Random Misfire

After that the following has been done:
Mechanic checked for any air leaks (forgive my description but I'm a noob at the mechanic stuff) by spraying some type of aerosol spray over the engine
Cleaned the fuel system out with some high end cleaner (name unknown)
Changed all the spark plugs
Checked the fuse ( which seems to have a little give (wiggles) when touching compared to the other fuses)

Today I used that sticky on how to get codes and I recieved the following codes:
PO 140 Circuit insufficient activity Bank 1 sensor 2-History

PO 154 Circuit insufficient activity Bank 2 sensor 1-History

P0155 - Heated Oxygen Sensor (HO2S) Heater Performance Bank 2 Sensor 1-Current

P0300- Engine Misfire Detected- History

I cleared the codes out and I'll drive it tomorrow to see what happens.

 

[jimsbox]

Jaison, check f 20 a red fuse in the under hood fuse block as described on previous post, it is Oxygen Sensors. Also, how did it go when you took it for a drive? You have a full set of spare fuses in the fuse block and inside the lid is the map to show where each one is, what size it is, and its purpose.

Let me know how it goes.

 

[Jaison]

Jaison, check f 20 a red fuse in the under hood fuse block as described on previous post, it is Oxygen Sensors. Also, how did it go when you took it for a drive? You have a full set of spare fuses in the fuse block and inside the lid is the map to show where each one is, what size it is, and its purpose.

Let me know how it goes.

I checked the fuse and the band wasn't broken. After driving it for about 15-20 minutes and checking the DTCs afterwards the only one I got was the P0155 - Heated Oxygen Sensor (HO2S) Heater Performance Bank 2 Sensor 1 (current). So this weekend I think I'm going to replace that sensor. While I do have instructions and a black and white picture I'm still not quite sure where the location is. From what I have been reading it is located on the underneath the car on the front passenger side along the exhaust pipe. Is this correct?

 

[jimsbox]

Here is a picture I took of the front HO2 sensor when I had the cradle out to stud the engine. The diagonal orange jack handle running diagonally at lower left is just below the sensor which is about midway up the jack handle. The aluminum block with the puddles of antifreeze is the ABS block. You can see from the top I think but if I recall you have to remove the air cleaner box and probably push the long radiator hose out of the way. Anyway, the ABS block is one the front driver side corner of the cradle so the sensor will be a little towards the center of the car above the front cradle cross bar. From underneath it looks to be above the point where the aluminum power steering return line crosses over the front cradle cross bar on the driver's side. Be aware that you are going to have AC lines, radiator fans, transmission connector, cradle cross member and numerous cables trying to occupy the same space as your hand when doing this, it will not be as accessible as it looks here.

Also, before you do all this, I would suggest you check the connector to the PCM (located inside the air cleaner box for cooling purposes) and the sensor pigtail to make sure that the connections are secure and undamaged. I would reseat the connectors on the pcm. Also, look for frayed wires from the sensor until they disappear into a wire bundle. The heater is controlled and monitored by the PCM.

Here is a close up of the sensor, I believe it is a 22mm socket or wrench. Be careful not to touch the business end (sensing bulb) when installing/handling the sensor. Don't forget to torque it if you can get a torque wrench in there. I did all 3 of my sensors while the cradle was in front of the car on jackstands, considerably easier than that which you are about to embark upon. Courage matey, there may be scraped knuckles and child inappropriate language ahead but you'll get it done. Before you embark on this I received a private message from Submariner409 that he would think about it and reply on this thread. I told him I wasn't certain I was on the right track (cat converter), you might want to give him a day or so to chime in. If you don't have the torque value I will try to look it up for you later today.

I think this is probably a 1 1/2 six pack difficulty level job when done in the car. May I recommend Heineken?

 

[Jaison]

Gulp!! I'm going to give it a shot anyways. Since I'm going to the junkyard this weekend I'll just practice on the one they got up there first. Hopefully Sub will chime in by then. I appreciate your help jimsbox especially the pics. I'll post an update this weekend.

 

[jimsbox]

Where do you live Jaison, I am in Kansas City.

 

[Jaison]

Where do you live Jaison, I am in Kansas City.

Virginia

 

[jimsbox]

Well, hopefully it will be nice and warm while you are working on it, beautiful country there.

 

[jimsbox]

How is it going?

 

[Jaison]

You were not exaggerating about it being difficult to access.:bonkers: It was a little to difficult to access from the top. So I ended up accessing to it from the bottom. The pigtail on the O2 sensor and it's connection seem to be good. The wires prior to the covering on the O2 sensor also looked good. In fact the wires looked so good not so sure they haven't been replaced before. But there is no way of me knowing though. I also checked the connection to the pcm and that seemed to be good.( Didn't reconnect it though) I'm actually going to replace it tomorrow. I was thinking while changing the o2 sensor may eliminate the po155 code and get rid of the service engine light. Will changing it stop my car from hesitating when accelerating? It seems like there may be two different issues going on here. Or are they related? Would a clogged catalytic converter or bad catalytic converter give me a DTC?

 

[Ranger]

Would a clogged catalytic converter or bad catalytic converter give me a DTC?

A clogged CAT usually won't. The engine just can't exhale so it will run poorly if at all. A bad (ineffective) CAT should set a DTC.

 

[Jaison]

I replaced the o2 sensor today and .......... it seems to have resolved my problem. Caught hell trying to take that thing off though. I let it run for awhile and I didn't get the P0155 - Heated Oxygen Sensor (HO2S) Heater Performance Bank 2 Sensor 1 message so it looks like all is well. I'm going to take it out this weekend for an extended cruise to make sure it doesn't come back. Thanks Jimsbox and Ranger for your help. Helping me resolve this problem was a hell of a introduction to the forum.

 

[jimsbox]

Sounds like you are home free. How many beers did it take? LOL. Imagine how it would have been without the forum, I really appreciate these guys and gals.

Jim

 

[Jaison]

I spoke a little too soon. The PO155 message came back.Help!!!!!!!

 

[Ranger]

A/C Delco sensor? Connector on tight?

 

[Jaison]

Bosch sensor, and the yes connector is on tight. The service engine light doesn't come on until the car pings and hesitates upon acceleration and then the light blinks on and off. According to the manual this a misfire, correct? In one of Jimsbox earlier post on the topic he stated it could be a clogged catalytic converter. Thoughts?