Alkatrez

I have the following codes; P0171
1. System too lean *fuel trim*
2. System too lean *A/T Lean bank1*
P0325
1. Knock Sensor 1 Circuit *bank1 or single sensor*
P0330
1. Knock Sensor 2 circuit
P1351
1. Variable Valve Timing/ CMP Sensor Range / Preformance
2. VVT Sensor / Cramshaft Position Sensor Circuit Range / Performance *Bank 2*
P1354
1. VV System *bank2*
P0171
1. System too lean *fuel trim*
2. System too lean *A/T Lean bank1*
--------------------------------------------------------------------------------------------------------------------------
Has anyone else had this issue with the '99 Lexus ES300 6 cyl 3.0L motor?

nsghtbrwry

Pretty common issues. I'd address the VVT oil valves first, then the knock sensors, then the lean code.

1. OEM oil valves should run you $50-60 apiece from Amazon (I used the Dorman units, they're working fine but I would obviously prefer OEM)...keep in mind the right and left banks have different (chiral) valves. Most common failure mode is getting choked out by sludge, so check if your engine is sludged up. Easy to replace, take off the beauty cover, undo a few coolant hoses above the thermostat to get clearance and they're right there. Oh, there's a filter behind a large (17mm?) bolt-cap near each valve, which you should pull and check for sludge as well. Clean the filters, and replace the sealing washers.

2. knock sensors are a bit more involved. You need to remove the entire intake manifold (plenum/upper intake AND lower/wet intake, i.e., you have to drain coolant), and they are nestled in the Vee. You should replace both sensors while you're in there, along with the knock sensor harness and water bypass hose (that hose will fail sometime, and when it does you'll be sorry). I used:

- http://www.ebay.com/itm/301835362641...%3AMEBIDX%3AIT . I strongly suspect these are knockoffs, but they worked great and looked exactly like the OEM sensors. DO NOT use parts store knock sensors: the Toyota/Denso knock sensors are resonant at 7 kHz, and a lot of off-brand sensors will just be non-resonant, picking up a large range of frequencies. They will throw the code and put your car in limp more over and over. Toyota/Denso sensors will have a hole, and aftermarket crap will have the hole covered (with a plate).
- . That's the harness.
- . And that's the bypass hose.

You'll need a 27mm shallow socket to remove and install the knock sensors. Torque is 29 ft-lbs.

After all this, clear the codes and see if any return, especially the P0171. Then you can begin troubleshooting that...check fuel trims, you probably have a broken/torn vacuum hose. HTH

nikovdh

P0171 could be as simple as cleaning the Mass Airflow Sensor (this is what fixed my code).


If you read live data on a scanner, the LTFT characteristics of a dirty MAF could be:

normal (-5 - +5 i.e. close to zero) LTFT on bank1&2 at idle
LTFT 25+ on bank1&2 during acceleration

While something like a vacuum leak will be like:

LTFT abnormal i.e. +25 at idle
LTFT lowers to a more normal amount on acceleration

I used CRC Mass Airflow Cleaner and a few shots from canned air before I went to bed. Re-installed it after I woke up. (just wanted to guarantee that it was dry lol, you probably don't need to wait 8 hours)

Also, the VVT codes are easy and inexpensive DIY fix. I recently had that at 162k miles (original OCVs), and I replaced both the oil control valves (bank 1 and 2) even though it only showed the code for bank 2 (<- I meant bank 1. I had code P1349, so I can't guarantee your fix is the same)
*EDIT* I meant bank 1

tomf

Did you get these codes all at once or over a period of time? It's highly unlikely that all these codes would appear simultaneously. If the codes appeared over a period of time follow the advice above. If the codes appeared simultaneously I'd be looking for something else, possibly the ECM.

nsghtbrwry

Great info, I don't have any codes but the PO put a Pick-n-pull MAF in my '99. It does that, LTFT jumps to 25.8 under acceleration, stays around -9 at idle. Not to hijack the thread anymore, but I'm going to order a Denso 197-6020 to compare.