JesLet

iTrader: (19)

I am getting a P0125 which is Insufficient temp for closed loop, and from what I read it also has something to do with oxygen sensors.

Can someone please help how to read this data so I know where to start. I think there is something wrong with STFT and LTFT.

JesLet

iTrader: (19)

I changed the timing belt and waterpump and flushed the coolant. New ECT sensor, OEM thermostat and new radiator/reservoir cap.

Brand new Denso O2 sensors, all 4 of them.

qewani1

When you got the code? after changing what u listed or before?

Did u used red coolant 50/50 with distilled water mixed?
Did u reset ECU? pulling battery negative cable and depress fully brakes

Am curious to know your current high way MPG?

Your ECT reading is fine, fuel trims are fine, despite of having LTFT <> zero, but total fuel adjustments is still within normal range +-10%

But IAT reading 57 is very low! but still it depends on outside temperature !

JesLet

iTrader: (19)

Code popped up after those parts are installed.

I am using Prestone green 50/50.. although i have Toyota Red which i also thought could be the issue. I dont know, ingredients are the same. Well, almost the same.

I just got this car, 1995 Ls400, i dont know where the gas mileage thingy on the cluster.

Car runs great... no hesitation or misfires. knocked on wood.

qewani1

Forgot about freeze frame data and start with below
Reset ECU by pulling battery negative cable and depress fully brakes m then reconnect cable and start the car, this will clear the trouble codes and will reset fuel readings...drive the car and check if CEL comes again or no!

Do u have any leaks in coolant?

If code re-appears then read live data when car idling and post them here..

when u changed thermostat...make sure you done it as shown in attached file!

dicer

Can you see real time data on that scan tool? Are the upstream O2 sensors both doing the fluctuating voltage deal? You may have a problem with one.

billydpowe

iTrader: (1)

I went thru po125 on my 99, checked all the water work systems and it turned out to be a leaking VCG on my o2 sensor that made is slow to work, cleaned it up and no more code..

JesLet

iTrader: (19)

all o2 sensors are new. As well as Valve cover gaskets,plugs, plug wires, PCV valve, distributor caps and rotors. Resealed all pans, all fluids are new.

JesLet

iTrader: (19)

I need to play with this scanner, i have no idea how to set it in real time. I should read the manual.

JesLet

iTrader: (19)

I believe its a wiring issue, does anyone know how to check voltage on each O2 sensor plug? Not the sensor itself but the terminal/plug where you plug the sensor.

I said wiring issue, just speculating because the wires on the injectors are really brittle, i rewrapped them with Super 33 electrical tape.

Yamae

Read the post #4 at below.
https://www.clublexus.com/forums/ls4...ure-yamae.html

JesLet

iTrader: (19)

Yamae,

The diagram on post number 4, when testing, are they only for pre-cat o2 sensors?

Thanks for the help guys!

qewani1

To read O2 sensor reading you can buy a cheap scanner which connects to PC like below one
http://www.ebay.com/itm/OBD-OBDII-Scanner-ELM-327-car-diagnostic-interface-scan-tool-elm327-USB-/121585673816?pt=LH_DefaultDomain_15&hash=item1c4f122658

Yamae

Yes, only pre-cat. Post-cat O2 sensors are not wired to the DIAG connector.