GS300 o2 sensor replacement.. now car won't start!
09-08-10, 04:35 PM
#1
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GS300 o2 sensor replacement.. now car won't start!
Hey guys,
My mom has a 2000 GS300 that recently threw a CEL for the front o2 sensor. Instead of purchasing an OEM replacement (or similar), I bought a universal heated 4 wire o2 sensor. While connecting the wires to the old plug, I accidentally touched two wires together, heard a "pop"- or something like a fuse blowing out. The car used to start up just fine, but now it doesn't start. Prior to this happening, I found the power wire (one of the four wires on the factory o2 sensor harness/plug had power) with a test light- and now it doesn't light up any more.
My OBD2 code reader keeps saying "error", and it seems like the car isn't sending any fuel to the engine. Additionally, the outside temperature reading on the head unit is blank. I know something shorted/grounded out- but the fuses look OK. Could it be the EFI relay?
It's likely something stupid/small that I'm not noticing with my own eyes... any ideas? Where else should I look? Thanks in advance.
By the way- I'm still rolling around in my 97 SC300. She's not boosted any more, but I still have it lowered, sitting on the LE37's, and rocking the w58 5speed tranny
. It's a head turner, but not too impressive in terms of performance 
My mom has a 2000 GS300 that recently threw a CEL for the front o2 sensor. Instead of purchasing an OEM replacement (or similar), I bought a universal heated 4 wire o2 sensor. While connecting the wires to the old plug, I accidentally touched two wires together, heard a "pop"- or something like a fuse blowing out. The car used to start up just fine, but now it doesn't start. Prior to this happening, I found the power wire (one of the four wires on the factory o2 sensor harness/plug had power) with a test light- and now it doesn't light up any more.
My OBD2 code reader keeps saying "error", and it seems like the car isn't sending any fuel to the engine. Additionally, the outside temperature reading on the head unit is blank. I know something shorted/grounded out- but the fuses look OK. Could it be the EFI relay?
It's likely something stupid/small that I'm not noticing with my own eyes... any ideas? Where else should I look? Thanks in advance.
By the way- I'm still rolling around in my 97 SC300. She's not boosted any more, but I still have it lowered, sitting on the LE37's, and rocking the w58 5speed tranny
. It's a head turner, but not too impressive in terms of performance
09-08-10, 05:20 PM
#2
Lets hope the fuses did their job and cut the power before you fried the ECU. Generally when connecting anything that even touches the electrical system you want to disconnect the battery. Wiring a powered sensor in while the car has battery power is best avoided... but I guess you figured that out already 
Sounds like the next stop will be checking all the fuses. (I believe) The GS has 2 locations for ECU fuses. One is just above the radiator on the right side, in a large black box, the other is a strip or another box just to the right of the drivers strut tower (if you are looking at the car from the front of the hood). use a fuse tester or look in the little windows at the top of the fuses. One (or more?) will probably be broken. Might want to use a nice flashlight. If you could hear the pop, you'll also want to check the fusible links in those boxes. They are very big fuses and normally don't come out like a normal fuse. They have bolts holding them in from the bottom.
Sounds like the next stop will be checking all the fuses. (I believe) The GS has 2 locations for ECU fuses. One is just above the radiator on the right side, in a large black box, the other is a strip or another box just to the right of the drivers strut tower (if you are looking at the car from the front of the hood). use a fuse tester or look in the little windows at the top of the fuses. One (or more?) will probably be broken. Might want to use a nice flashlight. If you could hear the pop, you'll also want to check the fusible links in those boxes. They are very big fuses and normally don't come out like a normal fuse. They have bolts holding them in from the bottom.
Last edited by tinman; 09-08-10 at 05:28 PM.
09-08-10, 07:18 PM
#3
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Lets hope the fuses did their job and cut the power before you fried the ECU. Generally when connecting anything that even touches the electrical system you want to disconnect the battery. Wiring a powered sensor in while the car has battery power is best avoided... but I guess you figured that out already
Sounds like the next stop will be checking all the fuses. (I believe) The GS has 2 locations for ECU fuses. One is just above the radiator on the right side, in a large black box, the other is a strip or another box just to the right of the drivers strut tower (if you are looking at the car from the front of the hood). use a fuse tester or look in the little windows at the top of the fuses. One (or more?) will probably be broken. Might want to use a nice flashlight. If you could hear the pop, you'll also want to check the fusible links in those boxes. They are very big fuses and normally don't come out like a normal fuse. They have bolts holding them in from the bottom.
Sounds like the next stop will be checking all the fuses. (I believe) The GS has 2 locations for ECU fuses. One is just above the radiator on the right side, in a large black box, the other is a strip or another box just to the right of the drivers strut tower (if you are looking at the car from the front of the hood). use a fuse tester or look in the little windows at the top of the fuses. One (or more?) will probably be broken. Might want to use a nice flashlight. If you could hear the pop, you'll also want to check the fusible links in those boxes. They are very big fuses and normally don't come out like a normal fuse. They have bolts holding them in from the bottom.
I heard a Pop, but can't seem to find a popped fuse
09-08-10, 07:27 PM
#4
heres why i love living in michigan( no emissions testing)CEL came on
1. turned out it was the cat and it was clogged up and needed replaced, so what i did was cut them suckas out and put in some straight pipes.
2. light came on again. for an o2 sensor, hell i didnt replace nothing i just removed the bulb lol, that was 40k miles ago, its got150k on the clock on it now, it gets about 100 miles on a quarter tank purrs like my cat rocky and drives smooth as hell. i looked under the car today when i did the back brakes and the o2 sensor thats the farthest back the wires on it are cut in half lol. i could care less car runs and drives perfect neve game me a problem in 4 years/80k miles
1. turned out it was the cat and it was clogged up and needed replaced, so what i did was cut them suckas out and put in some straight pipes.
2. light came on again. for an o2 sensor, hell i didnt replace nothing i just removed the bulb lol, that was 40k miles ago, its got150k on the clock on it now, it gets about 100 miles on a quarter tank purrs like my cat rocky and drives smooth as hell. i looked under the car today when i did the back brakes and the o2 sensor thats the farthest back the wires on it are cut in half lol. i could care less car runs and drives perfect neve game me a problem in 4 years/80k miles
09-08-10, 07:42 PM
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heres why i love living in michigan( no emissions testing)CEL came on
1. turned out it was the cat and it was clogged up and needed replaced, so what i did was cut them suckas out and put in some straight pipes.
2. light came on again. for an o2 sensor, hell i didnt replace nothing i just removed the bulb lol, that was 40k miles ago, its got150k on the clock on it now, it gets about 100 miles on a quarter tank purrs like my cat rocky and drives smooth as hell. i looked under the car today when i did the back brakes and the o2 sensor thats the farthest back the wires on it are cut in half lol. i could care less car runs and drives perfect neve game me a problem in 4 years/80k miles
1. turned out it was the cat and it was clogged up and needed replaced, so what i did was cut them suckas out and put in some straight pipes.
2. light came on again. for an o2 sensor, hell i didnt replace nothing i just removed the bulb lol, that was 40k miles ago, its got150k on the clock on it now, it gets about 100 miles on a quarter tank purrs like my cat rocky and drives smooth as hell. i looked under the car today when i did the back brakes and the o2 sensor thats the farthest back the wires on it are cut in half lol. i could care less car runs and drives perfect neve game me a problem in 4 years/80k miles
CA is tough/annoying when it comes to smog checks- which is due in 2 weeks for my mom's GS300.
09-08-10, 07:46 PM
#6
i totally understand, there is so many people here with muscle cars none of them have cats, half of the cars in michigan woudlnt pass inspection because they are all modified, the first thing you do to a mustang for example is get rid of the cats before you even put gas in it lol
09-08-10, 07:55 PM
#7
OP, just a little hint, if you bend down and look to the left side of the drivers foot rest, you'll notice a little door that pops out. Take that out and tell me what you find..
I'm pretty sure one of those fuse will be blown which is why it's not sending a signal to the fuel pump ECU.
I'm pretty sure one of those fuse will be blown which is why it's not sending a signal to the fuel pump ECU.
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09-08-10, 08:48 PM
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OP, just a little hint, if you bend down and look to the left side of the drivers foot rest, you'll notice a little door that pops out. Take that out and tell me what you find.. I'm pretty sure one of those fuse will be blown which is why it's not sending a signal to the fuel pump ECU.
I'm pretty sure one of those fuse will be blown which is why it's not sending a signal to the fuel pump ECU.I'll report back tomorrow with any updates. Thanks for the tips.
09-08-10, 09:01 PM
#9
dang, Alexus_300 beat me to it. Yup, there is a second (or third?) fuse panel. Based on the fact you heard a popping noise, i assumed it would have popped one of the fuses under the hood, but it could have popped one inside the cabin. Interesting that you specifically said you didn't think the engine was getting fuel; if the ECU isn't getting power or is broken (as evidence by your OBD II code reader showing error), then the ECU won't activate the fuel pump relay. But if the ECU is not working, you won't be getting spark either. 
If all the fuses check out ok, you'll probably have to test to see if voltage is getting to the ECU. This is easy to do, but I'll be damned if i can remember which pin you are supposed to test. *sigh*
If all the fuses check out ok, you'll probably have to test to see if voltage is getting to the ECU. This is easy to do, but I'll be damned if i can remember which pin you are supposed to test. *sigh*
09-10-10, 07:08 PM
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I checked all the fuses with a test light- they all seem OK.
The obd2 reader still shows ERROR, and the temperate gauge shows "--". The starter is spinning and I hear the engine crank, but it doesnt start up.
Does anyone know how I could check to see if the ECU is working/damaged/fried?
The obd2 reader still shows ERROR, and the temperate gauge shows "--". The starter is spinning and I hear the engine crank, but it doesnt start up.
Does anyone know how I could check to see if the ECU is working/damaged/fried?
09-10-10, 07:33 PM
#11
Check voltage coming into the ECU by checking pins 1 and 7 on the ECU, C connector (see colors on diagram which were supposed to be red but ended up pink). This is the 2JZ-GTE version, but i think it's the same pinout for the 2JZ-GE.
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