Z07

Mini ELM327 V2.1 OBD2 II Bluetooth Diagnostic Car Auto Interface Scanner (or newer) eBay <$10 landed

Use the included software ($0) or the Torque app ($5) with an android phone/tablet

salimshah

Knock sensor error will lock out the overdrive. It starts out slowly and lets you reset with every switch off of ignition and then you have to use the scan tool to reset. But it comes right back if the sensors are bad or the wire or the ecu.

Salim

Carista

Uhm... I don't mean to toot my own horn, but we've made what we claim to be the easiest-to-use OBD2 app in the world... so if all you want is a code reader to check/reset your OBD2 system (and show you emission test status, etc.), then look no further than Carista. It's available both on iOS and Android (for free) and we now have our own hardware adapter, which also works with both platforms and is reasonably priced at $39.99. Check out the links in my signature. Ok, I'm out

fastnoypi

: your supported vehicle page states your app only supports RX 2010+. OP's RX is a 1st gen.

Carista

We do support basic OBD2 diagnostics (the check engine light) on the 1st gen RX and all other cars since 1996 in the US. We don't support customizations or Lexus-specific diagnostics for the 1st-gen RX. Sorry about the confusion.

Jacklalane

I checked the voltages at pins 3&4 of my ECU. I can only assume that the E6 connector is the 4th one from the top. I am making this assumption because I can't find a diagram of the 89661-48130 ECU (mine) and it is the only connector that has a blue and a green in the 3rd and 4th positions (also they are larger than the rest of the wires in the ECU which makes me think supply voltage). The way I am interpreting the info you gave me is: Since neither of them are between 9-14V with the key on, which would indicate ECU failure (#3 blue is 3.40V and #4 green is 3.37V), I am thinking the ECU is OK. Does it seem like this is a correct understanding of the provided FSM info?

Assuming for now that is correct, I am going on to testing the resistance on the A/F sensors. When doing the high-temp resistance portion of the process, since it states that the data should come from "the component side" rather than the connector side, I'm guessing this must be with the sensor installed and the engine running and warm to achieve the called for high temp of 1472°F while testing. Is that the way you read it? And is it OK to temporarily install the B1 sensor in the B2 position where I can more easily access the pins with my VOM probes to check the hot resistance?
Thanks again for all of your help. I really appreciate it. Russ

Jacklalane

I have to get some sleep now before I go to work tonite, but I did get the B2 sensor tested. There is no continuity at all between B+ and H (or any other combination either). I went by the illustration I found somewhere on the site that had an image showing which wires (black and black) to test. I will check out B1 tomorrow. I didn't check for resistance hot...I couldn't think of any reason to with no continuity at all cold (and the resistance only potentially increasing with temp according to the directions).
Then I'll move on to the maf and the knock sensors...
BTW Salim, that is exactly where I am at: The overdrive resets with a switch of the key...I'm not to the phase where it takes a scanner reset yet (and I will fix it before driving any more).
Thanks to all who have chimed in~*

Jacklalane

Well, the "immovable object" met "the unstoppable force" and I'm happy to report the unstoppable force won again...After much cussing, head scratching and cussing I got the B1 AFsensor off the vehicle and tested resistance between B+ and HT. The result was the same as B2: infinity again...no continuity whatsoever.
Now on to cleaning the VVT screens and the maf check. Then deal with the knock sensors and harness. Since I can't test them, I guess it's time to dig in and replace them. I'm also thinking there will never be an easier time to replace the spark plugs and coils. Any other suggestions while I have things open would be greatly appreciated. Thanks for everything~*

fastnoypi

yes, i would agree the the ECU is OK as well.

I've never heard of nesting the A/F sensors while running. I've only tested at the o2 sensor connector side.
You are supposed to test the resistance at between the indicated wire pins for each sensor per the FSM instructions. Not continuity.

If you want to test if there is sufficient power going to the o2 sensor, you would probe the harness connector and look for 12V when your key is in the on position.

Youtube has a bunch of videos with troubleshooting o2 sensors with a multimeter you can use as a guideline, but be aware the pin outs they use may be different.

Jacklalane

Should I be able to reuse the intake manifold gasket or should I order a new one? Thanks

salimshah

Recommendation is to replace. IMHO it is not worth taking the risk.

Salim

Jacklalane

Thanks Salim,
I am seeing intake manifold gaskets for sale containing anywhere from 1-5 pieces...What am I needing for this job?
At this point I have in hand: air/fuel sensors, knock sensors and harness, plugs and coil packs, oem timing belt kit (which I'm thinking about taking to my tech). Can anyone think of anything else I'm missing that should usually be replaced at this time (other than normal shop supplies)?

salimshah

Sorry I am missing the context of your question.

Each of the DIY's has a list of items and some are missing the part number. Every one is encouraged to add to the DIY.

I would highly recommend to get hold of the service manual (volume 2, for mostly mechanical things). You will have the torque specs and also a picture breakdown and the parts that are recommended to to be replaced during service. To me the service manual is worth its weight in gold.

Salim

fastnoypi

you will only need the intake manifold gasket..the one that connects the plenum to the block if you remove the intake manifold off with the throttlebody. FWIW, i chose not to replace my gasket and sprayed it with copper gasket spray upon re-installation. Replace the gasket if it becomes bent or witness any damage.

If you do remove the intake manifold and plan to do the spark plugs, you might as well inspect your rear valve cover gasket and replace it as needed. they often get brittle and often leak oil onto the exhaust.

Jacklalane

I was wondering if I will be able to remove the manifold w/out separating the throttle body. I am just to that point. That is good news. I just called and our local AutoZone has the valve cover gasket set with the spark plug tubes attached in stock, so I will definitely take your advice and replace them. It will never be easier...I couldn't believe what a hassle I had removing the support bar between the strut towers. In order to lift the bar off of the studs it is bolted on to, I ended up having to remove the windshield wiper mechanism so I could lift the tray it sits in. Is that just the way it is, or can it be removed w/out doing that? I also noticed that the front tube of the pair of rubber tubes of the component that connects the throttle body to the air box had a little oil buildup at the place where it bends up (though my air filter is clean). How do I check the maf sensor to decide if it needs replaced? Can it be cleaned and reused, or is it something I just ought to go ahead and replace since it seems to be pretty inexpensive. I noticed looking in at it the small metal rod on the left looks to have some brown build up (varnish?) on it. I was wondering if I could clean it with some Xylene or Acetone and be good. I'm not trying to be cheap, I just don't want to be buying if it is just a waste and can be good since it is a component that is an easy access.

Salim, I am thinking I will buy the Vol 2 service manual today as you suggested. Is it something I can buy an online version of and have permanent access to? Could you post a link to it?

Thank you guys for all your help. It is greatly appreciated. Russ (Jacklalanne)