code 21

[jetjock]

Meh, it happens. The procedure is otherwise pretty creative. Course all of this would be simpler if he had a meter and knew how to use it.

 

[IBoughtASupra]

Thanks. I have heard that from long time electrical guys. I once traced a broken wire as to why the car was not getting pulse, but spark, this way. It is actually easier than it sounds.

 

[Late]

I will try this but I'm assuming it won't show a good ground seeing as when I use my test light to check the wire for o2-ecu groud it doesnt light up. Is the pin I'm looking for on the ecu labeled sensor ground and in the bottom corner, possibly e1? Currently don't have the pin out sheet next to me to check.

Thanks for all the help so far

 

[jetjock]

Assuming you have an 89 or later it's labeled HT (for heater). Pin 10 on connector R:

http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=48

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=50

 

[Late]

yes i have an 89, but after being confused multiple times from that diagram i thought that pin 10 was the power wire for the o2 sensor and not the ground, and pin 6 is the signal wire for the o2. does that mean +b and +B1 is power? i just got home and am going to check the wire shortly

 

[Late]

Actually I just found a digital multimeter, is there a better way I can try now?

http://i.imgur.com/m3BWy.jpg is what it is but i have no idea how to use it already blew up a few fuses attempting to follow the tsrm

 

[jetjock]

If you follow the other wire (B-R) from the sensor to the previous page you'll see it goes through the main relay to the EFI fuse. That's the power wire. You should have 12 volts on it at the sensor. The other wire from the sensor (B-L) going to HT is the ECU supplied ground.

Btw if you're going to use that meter move the red lead from "10A MAX" to the other side because if you try to measure voltage with it as shown in the photo you're going to blow stuff up...

 

[3p141592654]

JJ, the ECU reads HT current, so grounding the sensor HT line is going to set a code.

 

[jetjock]

Oops, that's right. Since I'm used to fooling it with a resistor I know better. Even alluded to it in post 27. Doh. Guess I was too focused on getting his heater working. Edits in place...

 

[Late]

is the ht line always supposed to have a good ground, or only when the car is warm? because i ran a new wire to it and it still doesnt have a good ground. ecu problem? i took it apart to look inside again and everything looks fine throughout the entire unit.

 

[3p141592654]

The HT line can be controlled by the ECU, so it can be either grounded and open-circuit depending on what the ECU commands.

There is a 0.56ohm resistor in series with a transistor (usually called T713) that controls the heater current. The line ultimately grounds to pin E01. With ignition on, you should see around 0.5-1.0 V on the HT line if everything is working properly.

 

[Late]

The HT line can be controlled by the ECU, so it can be either grounded and open-circuit depending on what the ECU commands.

There is a 0.56ohm resistor in series with a transistor (usually called T713) that controls the heater current. The line ultimately grounds to pin E01. With ignition on, you should see around 0.5-1.0 V on the HT line if everything is working properly.

wait. so it was working right when i first tested it and both heater wires lit up the test light showing power?

 

[3p141592654]

No, with the ignition on and the engine not running the HT line should be 0.5-1.0 V.

 

[87Burg7mgte]

did you ever find your problem here? i got the same issue going, but my code only activates when hitting higher speeds in the highway..(just replaced O2 sensor with a denso also)