cts circuit, code 21 info needed. 89 rx *issue resolved, duh!

[bluto5]

Since reinstalling my engine I have had a steady ecs light, o2 light blinking code 21.

 

I have been trouble shooting this problem abit but I dont have any idea what my known good values for the cts should be, there isnt any detailed info in the haynes manual. I also dont know if code 21 could be pointing in a another area besides just the cts.

 

I have also read through a few problems/solutions that I have found searching old posts. these seem to all be related to bad plug and contact issues.

 

The car iss usually about 30 deg. when I am working on it. I can get it to start with some pedaling/flooring of the gas pedal. It will run reasonably decent enough for a test drive but still not quite right. Idle is usually very high all the time. turbo was pretty cherry red after my last trip, timing has been checked( as near as possible with the idle where it is). The car never restarts when its hot.

 

With a dmm I am reading a short spike of 12ish volts to the cts when the when the ignition is turned to the on position. 12v returns once the engine is cranked. I get 12v if I am grounded on the engine or the other pin of the plug.

 

As for the grouund side, I have continuity to the engine and the neg terminal on the battery.

 

I have checked the wiring back to the engine harness plugs and found no resistance on the dmm.

 

 

 

I know on newer vehicles all sensor voltages are measured with a 5v current but I am a soob newb so this is all getting frustrating. any help or ideas would be greatly appreciated.

 

Thanks, Sam

 

ps for anyone who saw my thread dealing with my cv issue, After undoing the cv nut the joint popped onto the shaft with just a little effort. 1 problem solved, 1 to go.

[idosubaru]

if this is indeed a CTS code 21 issue then your contacts are at fault. dirt and corrossion is your problem, not the sensor. no need for any electrical measurements, this is a real easy fix. replacing the sensor is not the solution, though it may temporary alleviate it. i have a permanent fix to this recurring problem posted here:

http://www.xt6.net/forum/viewtopic.php?t=1767&highlight=coolant+temperature+sensor+fix

 

read through it and do as you see fit. i recommend the solder technique as there is no solid way to get the 20 year old stock harness connector back to acceptable condition on the ones i've seen.

[daeron]

i've been thinking about this... two ideas I have had about cleaning the female plugs on the harness..

 

The first is a simple dip with phosphoric or nitric acid. My landlord and I rebuilt our countertop stove about two years ago.. and we cleaned all the wires that went between the switches and elements with some nitric acid he had lying around.. takes copper from grease and rust stained, top bright pink.. kinda impractical, though..

 

the second idea I had was to find a piece of heavy gage wire used for wiring houses, and strip a small length.. peel back individual strands until you can JUST jam it into the plug, and then spin it, using the wire as a rasp or file of sorts to clean the inside of the female bullet connector..

 

since I think I may be having issues with mine, finally, i must try this, and report. any thoughts?

[bluto5]

grossgary,

I have voltage going into and coming out of the sensor, tested on the harness side of the plug, thats why I didnt feel that the plug and contacts are at fault. I am curious to know if you still feel that your fix is necessary, did your plug and harness test the same way?

 

I also pulled the leads out of the plug to check for corrosion in the wire itself and it was fine.

 

anyone else?

[idosubaru]

since i've owned about 15 XT6's and worked on others i don't need to test them. my newest daily driver i just picked up this summer is doing it too...so i'm off to do this YET AGAIN. i've seen it about 10 too many times in the past decade and this fixes it every time without buying a new sensor.

 

and to the question of cleaning the contacts - sure try it, but it's a waste of time. it will work temporarily for sure. maybe a month, 6 months, a year but it'll come back. that's what i did the first couple times i had to deal with this. tiny files, eyeglass screwdrivers...those really tiny microscopic kind work great at getting in there. there's no way to get it all out and if the system isn't sealed, it's going to happen again..just like it did the first time you needed to clean it. maybe you can grease it somehow and that will slow or stop the corrossion, but i like my current method it's the first and last time you'll ever do it.

[bluto5]

Sooo..

 

2 bosch injector female plugs about the same length at the same place on the engine harness. 1 has 12v+ and a grnd and goes to the idle control thing and the other has 5v+ and a ground and goes to the cts.

 

If you do not have these in the right place your car is not happy.

My car is now happy.

I am now happy.

 

After 2 months of waiting on parts, and dealing with frustrating silly problems my subaru is finally back on the road... and running on all 4 cyls.

 

now all I need is some snow.

 

Sam

[daeron]

Listen man, I REALLY don't want you to take this the wrong way...

 

But that was frickin hysterical.... Thanks for the laugh, sorry to be a jack@ss about it.

 

Come to think about it, go edit the subject line (please )to say coolant temp sensor rather than CTS.. the search function doesnt like three latter acronyms (go do a search on just cts and see how much you find. you think thats all we say about the CTS? or MAF, TPS, etc...) If someone else makes this mistake, it will help this thread show up in a search.

[idosubaru]

the same harness connector, interesting. that's a good one to know!