Evolving CEL - P0171 to P0330

[tystaco]

Looking for help. 2000 Limited with 164k. CEL is burned out, so only started finding codes once I got Torque Pro.

Started with P0171 - Bank 1 lean. Got rid of that code for a week or so (not really sure as it is my wife's car and didn't drive it much after) by changing the MAF 2 weeks ago.

Today I just thought I'd just check on her rig while I was driving it, and now I have P0330, bank 2 knock.

I found write ups on changing the knock sensors and harness. But I am looking for opinions on whether or not I have something else triggering these issues? They seem to close together. The vehicle seems to run fine after the MAF change, do not think I am experience the "limp mode."

If I change the knock sensors, there is no reason I have to change the valve cover gaskets right, just the gasket on the intake? I just had the valve covers done a few months back.

 

[Rock_Rat]

Looking for help. 2000 Limited with 164k. CEL is burned out, so only started finding codes once I got Torque Pro.

Started with P0171 - Bank 1 lean. Got rid of that code for a week or so (not really sure as it is my wife's car and didn't drive it much after) by changing the MAF 2 weeks ago.

Today I just thought I'd just check on her rig while I was driving it, and now I have P0330, bank 2 knock.

I found write ups on changing the knock sensors and harness. But I am looking for opinions on whether or not I have something else triggering these issues? They seem to close together. The vehicle seems to run fine after the MAF change, do not think I am experience the "limp mode."

If I change the knock sensors, there is no reason I have to change the valve cover gaskets right, just the gasket on the intake? I just had the valve covers done a few months back.

I've had both codes. The P0171 was/is MAF related and the P0330 is definitely knock sensor related.

Unfortunately, I became pretty proficient at changing the knock sensors. I went almost a year or perhaps longer, resetting the code. Anytime it would come on, I would reset it and go for another 100miles or so. Eventually, it got to the point where I had to reset it every five miles.

To answer your question: Only three things will trigger the KS codes.

1. Knock sensor bad
2. Sub-harness bad
3. ECU and or associated wiring bad.

You do not need to change your valve cover gaskets. Just change your intake manifold and plenum gaskets. Replace the $25 sub-harness and ONLY USE OEM sensors!! This is so critical!!!! It goes without saying, change both of them at the same time.

It's about a 4 hour job.

 

[tystaco]

[MENTION=116467]Rock_Rat[/MENTION], Thanks for the advice. I found your write up about it yesterday and appreciate you taking the time to discuss your experiences. I got the CEL bulb replaced and reset the code by disconnecting the battery. Went for 20 miles with no issue, but I've never been that lucky.

I am wondering if this is at all related to a vacuum leak? It just struck me as odd to have two different codes related to running lean back to back and only a few miles apart. I'd love to not have to do the knock sensors if it is just a leak, but will obvious do what I need to.

Any idea why I am not seeing a reduction in performance? Limp mode must not occur every time you get a P0330?

 

[Rock_Rat]

[MENTION=116467]Rock_Rat[/MENTION], Thanks for the advice. I found your write up about it yesterday and appreciate you taking the time to discuss your experiences. I got the CEL bulb replaced and reset the code by disconnecting the battery. Went for 20 miles with no issue, but I've never been that lucky.

I am wondering if this is at all related to a vacuum leak? It just struck me as odd to have two different codes related to running lean back to back and only a few miles apart. I'd love to not have to do the knock sensors if it is just a leak, but will obvious do what I need to.

Any idea why I am not seeing a reduction in performance? Limp mode must not occur every time you get a P0330?

From my understanding, and experience, the P0330 fault is actually the ECM reporting a faulty sensor/wiring. Unfortunately, the sensor doesn't control anything. It's job is to just report the status of the bank to the ECM using a VERY specific (OEM ONLY) voltage wave pattern so it can adjust the timing accordingly.

When you get the code, the ECM will put your rig into max retardation to protect the engine. This is one of the nine DTC codes that forces the ECM to go into fail-safe mode. You're indication that you went into "limp" mode is your gas gauge goes down faster than your RPM gauge goes up.

I've attached two screen shots from the manual. I actually had mine scoped at Toyota and saw the faulty wave pattern. The ECM is looking for something very specific from the knock sensors, completely unrelated to the P0171.

(However, I wouldn't completely rule out a rogue input as we've seen that before on here.)

Just out of curiosity, try setting one of your Torque Pro App codes to read "IGN". I'm pretty sure you'll see a change when the P0330 code come on.

I'll be monitoring this thread closely...

 

[tystaco]

Just out of curiosity, try setting one of your Torque Pro App codes to read "IGN". I'm pretty sure you'll see a change when the P0330 code come on.

I am pretty well still learning Torque Pro, can you instruct me on how to do this and I will share results. Is this in the code reading area or under gauges? CEL is back on today for P0330...40 miles from reset.

 

[Rock_Rat]

I am pretty well still learning Torque Pro, can you instruct me on how to do this and I will share results. Is this in the code reading area or under gauges? CEL is back on today for P0330...40 miles from reset.

I have the Scangauge II and "IGN" is one of the parameters I can load to check my ignition timing.

It should be a gauge function for the Torque Pro and not a CEL code function. I don't know for sure as I don't have it. (Try doing a search on here or check out their manual.)

Bummer on the code coming back. You can keep resetting it until you have time and parts to do the maintenance. Seems inevitable... Kinda sucks but it's still drive-able safely thanks to the ECM.

 

[tystaco]

[MENTION=116467]Rock_Rat[/MENTION] :Torque does not seem to offer that. I think a scangauge is in my future....and I might save enough if these knock sensors look legit to you to buy one!

https://www.amazon.com/gp/product/B073MRBS13/ref=ox_sc_act_title_4?smid=A24ADCU0DF1K71&psc=1

 

[Rock_Rat]

[MENTION=116467]Rock_Rat[/MENTION] :Torque does not seem to offer that. I think a scangauge is in my future....and I might save enough if these knock sensors look legit to you to buy one!

https://www.amazon.com/gp/product/B073MRBS13/ref=ox_sc_act_title_4?smid=A24ADCU0DF1K71&psc=1

Man if those sensors are legit, that's a screaming good deal!! I'd be tempted to buy an extra set just for myself...just in case...

If you're close to a dealer, have them pull one at the parts dept and do a comparison.

 

[tystaco]

[MENTION=116467]Rock_Rat[/MENTION] , Did you ever see the code reset itself? Parked over night...no light this morning. I know some codes will, but I guess I assumed this wasn't one of them.

 

[Rock_Rat]

[MENTION=116467]Rock_Rat[/MENTION] , Did you ever see the code reset itself? Parked over night...no light this morning. I know some codes will, but I guess I assumed this wasn't one of them.

Yes, I believe this is actually one of the codes that is reset with the ignition off. In other words it's not latched. As soon as you start it and run up to 1700 RPM or higher and the ECM doesn't see 7.1kHz the CEL will come back on. While driving you MUST reset the CEL which takes it out of limp mode until the next time...whenever that may be...10 miles, 40 miles, 100 miles...(Hopefully never.)

 

[tystaco]

Also just ordered a new thermostat, gasket, and ECT sensor. Figure if I am in there, it is all getting done.