P0141 And P0161 Simultaneously

[df2x4]

Some background info... The truck in question is my '97 K1500 5.7L Suburban. Factory exhaust, factory O2 sensors. Aftermarket Crimestopper remote start/keyless entry system which has been installed and relatively problem free for over 10 years.

For about a year now I've noticed that it will occasionally throw a SES light for a P0141, which signifies poor O2 sensor heater performance on bank 1 sensor 2. This only happens when I use the aftermarket remote start system a few times in a row. I thought that it might be a voltage drop issue (voltage is always lower than normal when started with the remote until the key is in the ignition) so I recently cleaned up my battery terminals and cables. That eliminated some voltage drop but unfortunately the P0141 popped up again tonight.

I recently purchased a clone Tech 2 scan tool so I connected that and noticed that there were also a couple of stored P0161 faults, which is the same deal but for bank 2 sensor 2. The P0161 doesn't pop up often enough to trigger a SES light like the P0141 does, but I can see it regardless with the Tech 2.

I already have one brand new spare OEM post-cat O2 sensor on my parts pile, so my instinct is to order another and replace them both. I suspect that the heating elements in both of them are just getting tired after all these years. I'm curious to hear if anyone else has any thoughts on this though, anything I'm missing or should check out?

 

[AK49BWL]

Could just be the sensors. But it's also possible, since the sensors are powered by the ignition switch usually, that the remote start relays or the wiring associated with it is not quite up to the task.

 

[F4U-1A]

Do not know if this helps. But once I had some O2 faults because I forgot to remove my rad air flow cover on my 96 5.7. Engine bay got really hot. Outside temp went from very cold to very hot one spring day. Once the cover was removed and I cleared the codes, all was good.

 

[df2x4]

Could just be the sensors. But it's also possible, since the sensors are powered by the ignition switch usually, that the remote start relays or the wiring associated with it is not quite up to the task.

I did think about this, but I would assume if this were the issue I would've seen one of these codes a long time ago right?

 

[AK49BWL]

Depends on how the wiring was done. I'd check for corrosion at the connections for the remote start unit before throwing parts at it. Also, both "Sensor 2"s are the farthest away from the power source, so any voltage drop is going to affect them the worst.

 

[df2x4]

Depends on how the wiring was done. I'd check for corrosion at the connections for the remote start unit before throwing parts at it. Also, both "Sensor 2"s are the farthest away from the power source, so any voltage drop is going to affect them the worst.

Good points, thanks!

Unfortunately the shop that did my remote start/keyless install is no longer in business (great sign, huh?) and I have no idea how they wired everything up or where the brain box even is. I'll take a look under the dash for anything obvious though.

I may just go ahead and throw both sensors at it and see if that fixes the problem. If it doesn't then that sounds like a good excuse to upgrade to a newer remote start/keyless system with a longer range on the remote.

 

[df2x4]

Current plan of action is as follows...

I cleared the codes and I'm going to keep driving it for the next week or so without using the remote start at all. Next weekend I'll plug the Tech 2 in again and see if there are any stored P0141 or P0161 faults. If they show up without me using the remote start (even if it's not often enough to trigger a SES light) then in my mind that points to the sensors themselves rather than a wiring issue.

 

[someotherguy]

Could just be the sensors. But it's also possible, since the sensors are powered by the ignition switch usually, that the remote start relays or the wiring associated with it is not quite up to the task.

Exactly what I was thinking and ya beat me to it.

I've noticed similar behavior (not the codes, just apparent lower system voltage) when my '06 is running in remote start mode - dash lights are a little dimmer than usual, for example. What I also noticed is not all the accessories are hot. Wipers would be one of 'em.

So here's my angle...on his truck, I wonder if it's an issue of simply lower system voltage due to poor quality relay / crummy circuit wiring on the remote start, OR, is the O2 sensor heater circuit even being powered when it's in remote start? Easy enough to check!

Richard

 

[df2x4]

OR, is the O2 sensor heater circuit even being powered when it's in remote start? Easy enough to check!

I would certainly think it is... As I mentioned the remote start system has been installed for nearly a decade and these codes have only started in the past year or so. Also the issue is very intermittent, sometimes I can use the remote start 10-15 times and not see a SES light, other times it triggers after only three or four uses.

I'm still leaning towards tired original sensors, but I'm curious to see the results of my testing this week.

 

[someotherguy]

I would certainly think it is... As I mentioned the remote start system has been installed for nearly a decade and these codes have only started in the past year or so. Also the issue is very intermittent, sometimes I can use the remote start 10-15 times and not see a SES light, other times it triggers after only three or four uses.

I'm still leaning towards tired original sensors, but I'm curious to see the results of my testing this week.

It's been a while since I've paid much attention to the conditions that must be met for the codes to set. There's an expected warm-up time before the O2 sensors begin generating current but I would imagine that's a shorter interval when they're heated sensors. It's either tired sensors as you are thinking, but don't rule out the length of time the truck is allowed to run in remote-start mode as a possible factor.

Hey; if they have a bunch of miles on them, no harm in replacing. If the codes persist then you'll know to look further.

Richard