SES light and 70k miles?

Rusty · Post by **Rusty** » Tue Jul 11, 2006 2:11 am

Hi guys. Been a while, hasn't it?

Anyway, we just had the SES light pop on in the CC yesterday right as it turned over 70k miles or somewhere near that. Wifes not sure exactly when it came on. I seem to remember reading here something happening right around that mileage mark but I can't find it. I'm going to run the codes when she gets home tonight but wanted to ask if there's anything I can look for besides just the codes.

Thanks!

Post by **HenryJ** » Tue Jul 11, 2006 3:21 am

I think codes are the best answer. Check the gas cap as that is a common trigger for the MIL.

The old VW bus had a "switch" that was oxygen activated. Basically oxygen degraded it to the point it would activate. Kind of a time delay. We do not have anything like that as far as I know.

Rusty · Post by **Rusty** » Tue Jul 11, 2006 4:16 am

HenryJ wrote:The old VW bus had a "switch" that was oxygen activated. Basically oxygen degraded it to the point it would activate. Kind of a time delay. We do not have anything like that as far as I know.

I know mine doesn't. At this point, there isn't anything stock or original back there! Interesting though. I didn't know about the oxygen switch.

I called Sharon at work and told her to check the gas cap (she just recently filled up). I'm also thinking the CC still has the original plugs, wires, etc. I was waiting for you guys to work out the cap issue and then just forgot about it all. The way Sharon is racking up miles on the CC, I can't keep up with the maintenance. Oh well, the codes will tell.

Rusty · Post by **Rusty** » Tue Jul 11, 2006 2:19 pm

P0155. Something about O2 sensor heater, Bank 2. Guess I know what I'm doing this weekend.

Post by **HenryJ** » Tue Jul 11, 2006 2:28 pm

Don't rush out and replace it unless you really want to.

It is not a bad idea to replace the O2 sensors as you near 100k. The performance does degrade over time as contamination becomes deposited.

Personally I would clear the code and see if it returns. I have seen this code surface once and never return.

You are not looking at a critical function here. This preheats the sensor so it can begin working faster. It does not say it has failed, only the heater did not respond as expected.

What do you have to lose by clearing the code and waiting for the second failure?

Rusty · Post by **Rusty** » Tue Jul 11, 2006 3:44 pm

HenryJ wrote:Don't rush out and replace it unless you really want to.

It is not a bad idea to replace the O2 sensors as you near 100k. The performance does degrade over time as contamination becomes deposited.

Personally I would clear the code and see if it returns. I have seen this code surface once and never return.

You are not looking at a critical function here. This preheats the sensor so it can begin working faster. It does not say it has failed, only the heater did not respond as expected.

What do you have to lose by clearing the code and waiting for the second failure?

Sounds good to me. Personally, I don't know what the new sensor costs but with my luck, it ain't cheap! I'll try clearing the code and see what happens. Thanks!

killian96ss · Post by **killian96ss** » Tue Jul 11, 2006 4:35 pm

Rusty wrote:
HenryJ wrote:Don't rush out and replace it unless you really want to.

It is not a bad idea to replace the O2 sensors as you near 100k. The performance does degrade over time as contamination becomes deposited.

Personally I would clear the code and see if it returns. I have seen this code surface once and never return.

You are not looking at a critical function here. This preheats the sensor so it can begin working faster. It does not say it has failed, only the heater did not respond as expected.

What do you have to lose by clearing the code and waiting for the second failure?
Sounds good to me. Personally, I don't know what the new sensor costs but with my luck, it ain't cheap! I'll try clearing the code and see what happens. Thanks!

New sensors are usually $40-$50 each. I always replace mine around the 60k-70k mark. You can wait until 100k, but they will be very worn out by then and your gas mileage will have been suffering for the past 30k-40k miles also.

Changing the 02 sensors is probably one of the easiest things to do. The 2 pre-cat sensors are way more important than the post-cat sensor since they are responsible for keeping the engine running at peak efficiency. All the post-cat sensor does is verify that the catalytic converter is doing its job.

Steve

Rusty · Post by **Rusty** » Tue Jul 11, 2006 4:56 pm

killian96ss wrote:New sensors are usually $40-$50 each. I always replace mine around the 60k-70k mark. You can wait until 100k, but they will be very worn out by then and your gas mileage will have been suffering for the past 30k-40k miles also. Changing the 02 sensors is probably one of the easiest things to do. The 2 pre-cat sensors are way more important than the post-cat sensor since they are responsible for keeping the engine running at peak efficiency. All the post-cat sensor does is verify that the catalytic converter is doing its job.

Steve

Thanks Steve. I'm going to try clearing the codes tomorrow, just to see what happens. I'll keep your advise in mind but I can't really afford to replace all the sensors right now. Money is just a bit tight for the next few months!

WVHogRider · Post by **WVHogRider** » Tue Aug 15, 2006 2:44 am

SES light came on this morning.

I noticed HJ told Rusty to check the gas cap. Since I've been out of town a lot, I had just switched over to an aftermarket Locking Gas cap.

Can I just stop by an Advance Auto/Autozone to check/clear the code?

Post by **HenryJ** » Tue Aug 15, 2006 3:19 am

They should be able to read and clear the code with a scan tool.

Another method is to disconnect the battery cable. Make sure the radio does not have Theftloc enabled first. Disconnect both ables for 3 minutes just to be sure. I can't say why both and why 3 minutes, but seem to remember something about the positive cable and capacitor discharge? Anyway it can't hurt.

WVHogRider · Post by **WVHogRider** » Tue Aug 15, 2006 3:50 am

Alright. I'll try the battery disconnect method tonight, as I have to remove the battery again anyway to flush the radiator cleaner/water out and put in the green stuff. I was able to flush the dex out, refill with cleaner & water, and install the Jet thermostat this past weekend. Now I'll just have to figure out how to disable the anti-theft feature on the radio.

Then if it doesn't go away or comes back, I'll go to the store to check the code.

Should I switch over to the original gas cap after I disconnect the battery? Just to see if it may be the problem.

Thanks HJ.

Post by **HenryJ** » Tue Aug 15, 2006 12:59 pm

WVHogRider wrote:...Should I switch over to the original gas cap after I disconnect the battery? Just to see if it may be the problem.

It is up to you. If you think that was the problem, it might be a good idea.

WVHogRider · Post by **WVHogRider** » Mon Aug 21, 2006 7:07 am

I removed the battery to do the radiator flush/refill, and put the OEM gas cap back on. SES light has been gone for almost a week now.

WVHogRider · Post by **WVHogRider** » Wed Aug 23, 2006 3:28 am

Must have jinxed myself, SES came back on last night. I will stop at the auto part store to get the code in the next day or two.

WVHogRider · Post by **WVHogRider** » Fri Aug 25, 2006 6:39 am

Got the codes cleared yesterday on the way home. The first code was for the locking gas cap that I had put on, which I went back to the using the original. The second and most recent code, PO141, was the O2 heater malfunction. I will wait to see if it relights the SES again and then replace the O2 sensors.

killian96ss · Post by **killian96ss** » Fri Aug 25, 2006 8:29 am

WVHogRider wrote:The second and most recent code, PO141, was the O2 heater malfunction. I will wait to see if it relights the SES again and then replace the O2 sensors.

If you do have to replace the 02 sensors make sure you use GM, AC Delco 02 sensors since most of the aftermarket sensors like Bosch only cause problems and reduced fuel economy.

Steve

WVHogRider · Post by **WVHogRider** » Tue Aug 29, 2006 2:12 am

Got the SES light again this morning coming to work. Will stop and get the code checked on the way home this afternoon. What auto parts store sells the AC Delco sensor, as I can't find one at Autozone, Advance or NAPA?

2kwik4u · Post by **2kwik4u** » Tue Aug 29, 2006 4:01 am

killian96ss wrote:If you do have to replace the 02 sensors make sure you use GM, AC Delco 02 sensors since most of the aftermarket sensors like Bosch only cause problems and reduced fuel economy.

Steve

Is this founded on personal experience or some reading somewhere? I've used Bosch sensors in just about every car I've owned, and also use a Bosch sensor in my wideband setups that I've had. They've all worked just fine, and I've had ZERO problems with them.

killian96ss · Post by **killian96ss** » Tue Aug 29, 2006 7:38 am

2kwik4u wrote:
killian96ss wrote:If you do have to replace the 02 sensors make sure you use GM, AC Delco 02 sensors since most of the aftermarket sensors like Bosch only cause problems and reduced fuel economy.

Steve
Is this founded on personal experience or some reading somewhere?

I thought it was well known that GM vehicles run best with GM AC Delco 02 sensors vs most aftermarket 02 sensors.

I have personally had too many problems with Bosch and other aftermarket 02 sensors to ever use them again on any of my GM vehicles.

My SS runs like crap with Bosch 02's (surging, erratic idle, increased emissions).

I had a 98 Malibu that did almost the same exact thing with Bosch 02 sensors.

Most if not all the B-body and F-Body forums warn people about problems with aftermarket 02's and recommend only AC Delco sensors as replacements.

Steve

WVHogRider · Post by **WVHogRider** » Tue Sep 05, 2006 6:49 am

OK. So I got the codes cleared again, PO141 and the one for the gas cap again. So I bought the one Bosch O2 sensor cause I couldn't find the AC Delco O2. I noticed that the stock O2 sensor had 8 slits in the sensor cone, and the Bosch O2 sensor only had three slits in the cone. Truck ran fine since last Tuesday when I replaced the middle O2 sensor, and went back to the locking gas cap. And then last night, the SES light came back on. So I guess I'll be stopping at Autozone to get the code read/cleared again. Any ideas what else needs done? IE-Move the IAT?

F9K9 · Post by **F9K9** » Tue Sep 05, 2006 7:14 am

The code that relocating the IAT corrects is for low coolant temperature is PO128. I don't think that is gonna help you.

killian96ss · Post by **killian96ss** » Tue Sep 05, 2006 1:08 pm

WVHogRider wrote:I bought the one Bosch O2 sensor cause I couldn't find the AC Delco O2. I noticed that the stock O2 sensor had 8 slits in the sensor cone, and the Bosch O2 sensor only had three slits in the cone.

This is just one of the reasons why the Bosch 02's don't perform the same as original GM 02's.

When you can see an obvious difference in the way the exhaust gas passes over the sensor then that's just not good.

I wouldn't recommend running different brand 02 sensors in the right and left banks.

Take your Bosch 02 sensor and install it after the cat and replace your right bank 02 with the original GM 02 sensor that you just pulled from after the cat and see if that does anything.

If that doesn't work then try removing the left bank 02 and replacing it with the (right bank) GM 02 that you originally replaced with the Bosch 02.

One of your 02 sensors is faulty and the only way to find out which one it is without a scan tool is to replace them one by one or try switching them around.

Steve

Post by **HenryJ** » Tue Sep 05, 2006 1:50 pm

I have not had problems with Bosch O2 sensors. The design difference has not created issues with the ones I have replaced in the fleet.
I have found that when one fails the others may not be far behind. They seem to fail in a cascade. If it is a vehicle that has some time left to serve in the fleet I usually replace them all when one fails.
The newer heated O2 sensors have a much lower failure rate than prior models , so unless you have quite a few miles on your truck, don't suspect the sensor quite so quickly. Maybe look for other issues and carefully test the O2 sensor prior to replacement.

When I get a code from an O2 sensor, I clear the code and see if it returns before looking further. Sometimes they never return.

WVHogRider · Post by **WVHogRider** » Wed Sep 06, 2006 2:06 am

OK. I got the code cleared. The only code that showed this time was the gas cap. Eventhough I already bought a brand new locking gas cap, I now need to buy a replacement OEM gas cap, as I have gotten the code with both the origianl and new locking gas caps.

Post by **HenryJ** » Wed Sep 06, 2006 2:36 am

Have you checked the filler neck for a crack?

WVHogRider · Post by **WVHogRider** » Wed Sep 06, 2006 4:15 am

No, not yet. I will look after work, but it should be fine, as I have not done the body lift nor have I done any type of offroading to cause the filler neck to crack. Just normal road driving. The technician who cleared the code did say that it could be a vaccum problem instead of the cap. Actually, I filled up last night and there was no fuel leakage that I noticed.

Post by **HenryJ** » Wed Sep 06, 2006 5:21 am

Hows your heater controls and the transfercase switch?

WVHogRider · Post by **WVHogRider** » Wed Sep 06, 2006 6:35 am

Both have been operating properly.

killian96ss · Post by **killian96ss** » Wed Sep 06, 2006 9:45 am

HenryJ wrote:Have you checked the filler neck for a crack?

I don't think it is your gas cap either and like Brule already pointed out it seems like you have a leak ocurring somewhere else causing your problem.

I've been running an aftermarket locking gas cap for 80k + miles with no problems.

Steve

WVHogRider · Post by **WVHogRider** » Wed Sep 06, 2006 10:10 am

I wonder if there could be a slight leak around the fuel filter, but I haven't seen any fuel spots under the truck after I shut it down. The fuel filter is the only thing I have changed in that system.

Now see what happens when I listen to you guys, I should have waited until 100K to change it.--J/K I'll try to take a look at the whole system tonight.

Post by **HenryJ** » Wed Sep 06, 2006 1:06 pm

I have been having similar issues with a couple of the trucks in the fleet. New caps worked the first time, but they are having problems again.
The first thing I check is the cap for signs of dust. When the pressure valve in the cap leaks. Dust is drawn into the filler neck via the leaking valve. It is usually pretty easy to see. These trucks run in a cloud of dust most of the day.

Now if the cap is good I have to look else where. A couple of them have received new fuel pumps, so I will have to go back and check all the connections to make sure they are tight.
The next suspect may be the vacuum solenoid, or perhaps supply. Much harder to trouble shoot.
I will let you know if I happen to find anything. I really hope you find something first though

border man · Post by **border man** » Wed Sep 06, 2006 3:31 pm

I had the same problem a while back, tried the gas cap and nothing. I ended up tightening the hose clamps on the filler hose(top and bottom) and voila!! no more SES light for over a year. My tank never leaked gas although both clamp were loose. Another place to check is the rubber O-ring in the cap itself. It may be dry-rotted( this may not be the cause in your situation since you have changed caps)

Post by **HenryJ** » Fri Sep 08, 2006 11:07 am

Borderman nailed it on the first truck I had the opprotunity to check. A loose clamp on the filler neck. :fingers crossed: That should fix that one.

WVHogRider · Post by **WVHogRider** » Mon Sep 11, 2006 2:23 am

I never got around to checking last week. I'll try to check it tonight.

WVHogRider · Post by **WVHogRider** » Mon Sep 18, 2006 3:25 am

OK, how in the world did any of you get to the bottom clamp to tighten?

I was able to get at the top clamp, but it was still tight. The only way I can even get near the bottom clamp is by looking at it from between the cab and the bed.

I can't get one of my big old paws near the clamp to try and tighten it. I may just make this a dealer item to fix/figure out. I will try to attempt tightening the fuel filter again tonight, ( I never got to try the filter yet as the neighbors and daughter are always interupting me or needing something).

WVHogRider · Post by **WVHogRider** » Wed Oct 25, 2006 2:30 am

For some reason, the SES light was not on today,

and I haven't touch a thing.

Post by **HenryJ** » Wed Oct 25, 2006 3:11 am

If the condition no longer exists and a set number of ignition cycles passes the light may go out.

WVHogRider · Post by **WVHogRider** » Thu Jun 14, 2007 10:28 am

killian96ss wrote:Take your Bosch 02 sensor and install it after the cat and replace your right bank 02 with the original GM 02 sensor that you just pulled from after the cat and see if that does anything.
Steve

OK, so I was reprogramming the truck to 93 a week or two ago, and the code PO141 showed without the light coming on yet.

So I cleared it. It's been nice so I've been on the HOG lately instead of in the truck.

This morning the SES light comes on. The codes turn up to be PO141 & PO442 again.

I think I'm going to take Steve's advice & switch the O2's around to put the Bosch past the cat. converter to see if the code switches. I now have 88K on the truck, So do you guys think I should just bite the bullet and get all three new O2s? (Previous sentence really means I'm low on funds, and still have to fund another OOPS that I will start a new thread on). I've also started to notice some weird variance when idling, but unsure if is due to the Bosch O2 sensor or not.

I'm not sure what to do about the Evap leak Code besides a new gas cap. I never did get a third new cap.

I was just using the original and the locking one stated previously.

Filler neck & fuel filter were tight last time, but I'll check again.

I haven't filled up in quite a while. I just put $20 in this morning, so I'll check for codes again once I get home.

killian96ss · Post by **killian96ss** » Thu Jun 14, 2007 10:54 am

WVHogRider wrote:I think I'm going to take Steve's advice & switch the O2's around to put the Bosch past the cat. converter to see if the code switches. I now have 88K on the truck, So do you guys think I should just bite the bullet and get all three new O2s?

At 88k miles those 02's are about done.

Try switching them around like I mentioned, but if that doesn't work then I would recommend replacing the 2 pre cat 02's with some Delcos and keep the newer Bosch 02 in the post cat position.

This will save you at least $60-$70 over buying all 3 new.

Steve