mt_goat

Make sure you properly solder and wrap/heat shrink the wiring.

On the scanner, do you have a laptop? If so, you can get a connector/converter and use your laptop.

xrannie

installed the urd simulator. disconnected the battery first.
i soldered the wires good.
hooked battery back up and it barely started. didn't touch the gas. started up and it just bumbled at about 800 rpm.
let it run for about 30 seconds, went down the road and back getting it up to temp.
when i parked, i let it run and it idled normally. turned it off, waited about a minute- tried to start, and i have to give it gas to get it to start. CEL light is off & it wont run right- or start right.

any suggestions?

would that mean my catylitic converter might be stopped up?

THANKS

xrannie

ok.. been out playing with the taco.. she starts up fine with a pat on the gas peddal. with engine cold- i had to revv to about 1100 and hold it there for about 15-30 seconds. then she was good to go until i turned the key off. idled fine. ran great.

with motor warm, i just had to pat the gas and rev past 1500-2000 rpms and let off the gas, it idled back down and held normally.

mt_goat

Not sure but it could be the ECU relearning the fuel/timing maps after the memory being cleared (pulling the battery cable off for 10-15min clears the ECU memory of its fuel/timing maps).

vital22re

iTrader: (2)

perhaps the wiring is not done corectly. make sure you properly identify the factory wires before you solder them to the urd sim.

mt_goat

X2, if you say spliced into the front sensor unstead of the rear sensor you would definately have problems.

xrannie

yeah, i was super-anal about following the instructions/soldering. the pin #s and wire colors described in install sheet for my year/make were perfect.
i was so excited when i got done, i put everything back together before i tried starting thank goodness i did it right.
i let it run for about 20 minutes after i drove it again. left it sit overnight. got in to go to work this morning and she fired right up like she used to!!
100 miles-no code yet. Started right up on my lunch break and the two times when i worried so much i lied about having my medicine inside the truck... lol i drove pretty hard on the way home and she was begging for more...

Thanks a lot for the suggestions everyone.. i'll let you know how she does on the trip.

cool sticker from urd..




UTAH OR BUST!

X-AWDriver

Ok,bringing a thread back since it had no real conclusion.

After wheeling today my truck threw a PO420 code and tomorrow I plan on pulling the battery cable and see if it's a real issue or not but if it is I want to see if anybpdy had any new info on fixes or solutions. And my truck is a Cali emissions model.

BigBallsMcFalls

yes it is a either a real issue or the o2 sensor is just dead

best fix is a new oem front sensor and rear sensor. have an emissions test to
see if the cat is really doing it's job or not first

X-AWDriver

The truck runs fine (even my MPG was up) so for the immediate future I'll just try to reset the ECU and see if the CEL comes back on. I'm trying to be frugal at the moment and replacing both sensors would be pricey but if that's what I gotta do I'll do it.

TheDurk

Well, you can replace one sensor at a time to try to save $$. If you have service records, replace the older one first. If you have no records and 125k+ miles it's a crap shoot. Front sensors die sooner in general. However, rear sensors on a Cali. are cheaper and a solo P0420 (NOT PO420, if you are searching) is more likely due to the rear sensor. Take a look at the nuts on the sensors. If the front ones are in better shape, then I would definitely change the rear sensor first. The nuts tend to be pretty rusted up by the time the sensors fail and will usually need to be replaced.

The P0420 is two-trip detection and a lot has to happen before the ECU completes its test. So the CEL will go off at first and may take 50-100 miles to return. So don't get your hopes up until the second tank of gas.

AlexJet

I'm having this code for over 6 month now and keep cleaning with ScanGauge. The problem with disconnecting the battery is that it will get the light off, but your ECU has permament memory which only can be cleaned by "dealership" type scanner (very expensive, so not every shop has it). So the code will come back at some point if issue is there. It also affects your engine performance and give a bit richer mixture, so a bit more gas. I'd replace my sensors or cats under warranty, but having JBA headers cancells all my tries with the dealer.

Try to start with sensors as they are cheaper. Worst case it will be the cat. And yes, better stay with OEM if finance dept approves it.

mt_goat

So are you saying how the code is cleared makes a difference in how fast the CEL comes back?

AlexJet

It doesn't matter on "Check Engine" light as it only comes when you have a bad signal and system does checks every xxx hours. Then when it lights up. The issue is that permanent memory still has the code and may adjust your ECU accordingly. Meanwhile I know that physically light ON also makes a few changes to ECU program. So I'd say having just hidden code makes a small difference, but having light ON makes even bigger difference. Switching light OFF doesn't make error disappear, its like illness - you treat only results, but not the cause.

Ironmike4x4

Keep in mind I'm talking from GM experience but you are talking about hard vs. soft DTCs. Emissions DTCs will immediately set an CEL after certain criterias for a failure. After several driving cycles and the parameters are met the CEL will turn itself off but will set a hard code in the PCMs memory until numerous drive cycles where it passes. I will say from experience disconnecting the battery and then rechecking the PCM for a history or hard DTC will not appear, but keep in mind this is from GM experience. A soft DTC is usually a minor malfunction and will usually not turn on a CEL nor store a history code. Yes Alex is right about the ECU making corrections, for us it's called "Limp mode" where the vehicle defaults to certain parameters just to get the vehicle to safety. Some of GMs transmissions and AFM (active fuel management) codes will allow this. Toyota may do it differently so I'm not going to make a correction either way.

As far as the OP's problem. I'd get a good scan tool and check the O2 sensor parameters. The both B1 and B2 S1s (pre cat) should fluctuate rapidly 200mV to 800mV during closed loop compared to the S2s (post cat) which should remain steady usually around 600-700 mV. If the sensors look good then usually our diagnostic tree tells us to check vacuum to condemn or eliminate the coverters. 80% of the time for us in GM it's a bad converter though I've had a few fool me.

According to Alldata tree it says to inspect B1S1 O2 sensor, if okay then inspect B1S2, if okay then to replace converter. If not okay on either sensors then to repair or replace. I'd say you'd be better off using a scan tool and looking at the sensors to see what they are doing, it's quicker and easier believe me.

Edit: apparently our 4Runners only have 2 O2 sensors so disregard any references to bank 2 sensors.

X-AWDriver

Well,I disconnected the battery which got rid of the CEL but I expect it to pop up sometime but as long as my truck is running fine and still get's it's average MPGs I'm not going to worry to much right now.

mt_goat

I remember when congress was investigating the Toyota recall problems earlier this year, they said the ECU has info stored that was so secret there was only one special laptop in the US that could be used to access the info.

BigBallsMcFalls

well, 'mpg up' can mean the system has become running too lean and yes, engine performance gets better, mileage increases as a result. but BAD things
will happen if it continues running too lean

X-AWDriver

MPGs being up I mean a small 1mpg at the most and I was on the highway a bit more than usual.

wyoming9

iTrader: (1)

I had the same code replaced the exhaust system from the down pipe to the tail pipe with a stock Walker system. 2000 Tacoma 3.4

Got two new Denso sensors from URD the code cleared and has been good since about 5 months