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Guest Message by DevFuse
 

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NEED HELP..code 21 (coolant tempsensor...-now starting..?


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9 replies to this topic

#1 bgambino

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Posted 02 January 2005 - 07:05 AM

After 2 hours ...went out and car starts fine...!wtf.....maybe I did not explain my problem this morning very well....you guys were suggesting thermostat...?...the car was NOT starting....7 fast flashes on the ECM with key in the on position--BTW:ANYONE KNOW WHAT THE 7 FLASHES MEAN?>>>NOTHING WRITTEN ABOUT IT THAT I CAN FIND....
Drove it ten miles and back...seems OK..but a little leary about what is going on---temp still is at about 1/4 on gauge like before but heat is ok

Dealer did not have a thermostat (figured I would change it anyway)--bought one from carquest----In 24 years owning many sub's, I never had a problem with non OEM thermostats----cant change it now...its a blizzard here in SE NY
*******************************
OK....seems you guys were right...ohm resistance reading on old thermosensor were non existent---got new one from 1st subaru (that place is a great find...thank you
went out to start car to move it...0 deg F out....stalled quuite a few times as it runs rough with bad sensor----took out old,,,put in new---(could wiring be any shorter...god)----turn key and she fires up quickly....and immediately dies....now cranks and will not even cough....ECM with key on is blinking 7 fast flashes (this is a 91 loyale non turbo auto 4wd wagon with SPFI)
Disconnected batt...and reconnected...nothing different
I read that to clear codes to connect two connectors by firewall in eng compartment by wiper motor (info I have says these should be green and other black...I have green and other is white)
connected both and still no start---engine is cold BTW

While green is connected with key on there is a rythmic click...on...off...on...off(somewhere on manifold and also on something on top of the ECM)
What the hell is going on?
Anyone???we got 12 " coming today



Just got this baby on the rode..was running great...check eng. lite comes on when I start it (idle is low and it hesitates) ---I drive it and lite goes off after 4-5 miles(after a mile or two, the idle is actually kind of high when I stop, 1800RPM.)..---when lite goes off ,she runs smooth

book says coolant temp sensor or circuit
I cleaned the connector blade on the coolant temp sensor (was a little green) hoping for an easy fix....no luck..lol

Anyone know a simple way to diagnose...hate to buy one if not the real problem

I am assuming the computer thinks the engine is warm and is sending the wrong fuel/air mixture

I had put a new theromstat in a few weeks ago when I did timing belts---funny that this car temp gauge reads about 1/4 high when at temperature where all my others ran at exactly 1/2---its got plenty of heat and the elec fan comes on and off OK---was thinking I should go in and push needle up a little (I think I had done that with the gas gauge needle years ago on another Sub. and it holds the new position--anyone ever try this?.....I am a little anal about the gauge reading where it should..LOL)
thanks

#2 Skip

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Posted 02 January 2005 - 07:50 AM

Sir there are two coolant sensors

One for the gage (the one you cleaned the spade terminal on)
and
One for the fuel injection ECU

The one that is giving you a engine check light
is the second.

On the goose neck housing where you found the first unit

there is another, this one has a pigtail going to a connector.

You could try cleaning the connections but a replacement
is probably in the cards

I'm sorry I do not know how much they cost.

#3 bgambino

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Posted 02 January 2005 - 08:05 AM

Skip..thanks...

but where exactly is this other sensor and what does it look like?
The one I know of is on the pass. side of the intake.
Are you saying it is a sure bet that it is bad?
Any way to test?
thanks...you are a real asset to the board!
Bill

Sir there are two coolant sensors

One for the gage (the one you cleaned the spade terminal on)
and
One for the fuel injection ECU

The one that is giving you a engine check light
is the second.

On the goose neck housing where you found the first unit

there is another, this one has a pigtail going to a connector.

You could try cleaning the connections but a replacement
is probably in the cards

I'm sorry I do not know how much they cost.



#4 Skip

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Posted 02 January 2005 - 08:32 AM

I'm sorry I did not describe the location in enough detail for you.

The housing where the upper radiator hose connects has two sensors

Both threaded into the housing and facing toward the outboard side of the car. .

one is threaded in at an angle.
this one is for the dashboard temperature gauge.
The FSM calls this the thermometer.

one is threaded in horizontally below and more towards the front of the engine
and has a set of wires permanently attached.
This is the FI coolant thermosensor

You can test it.
The readings should be as follows
H20 Temp (deg F)_______Res. (ohms)
14____________________7-11.5 k ohms
68____________________2-3 k ohms
122___________________700 - 1000 ohms


as for the dash gauge sensor it can also be tested in a similar fashion
but has different values.

Once again I am sorry for the lack of detail in my original post.
Hope this helps

May I add that since no fuel injection type was
mentioned I am assuming SPFI

#5 MilesFox

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Posted 02 January 2005 - 08:49 AM

the one with 2 wires going to a green clip.

#6 bgambino

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Posted 22 January 2005 - 10:49 AM

Guys please look at new development....HELLLLPPPPP

OK....seems you guys were right...ohm resistance reading on old thermosensor were non existent---got new one from 1st subaru (that place is a great find...thank you
went out to start car to move it...0 deg F out....stalled quuite a few times as it runs rough with bad sensor----took out old,,,put in new---(could wiring be any shorter...god)----turn key and she fires up quickly....and immediately dies....now cranks and will not even cough....ECM with key on is blinking 7 fast flashes (this is a 91 loyale non turbo auto 4wd wagon with SPFI)
Disconnected batt...and reconnected...nothing different
I read that to clear codes to connect two connectors by firewall in eng compartment by wiper motor (info I have says these should be green and other black...I have green and other is white)
connected both and still no start---engine is cold BTW

While green is connected with key on there is a rythmic click...on...off...on...off(somewhere on manifold and also on something on top of the ECM)
What the hell is going on?
Anyone???we got 12 " coming today



Just got this baby on the rode..was running great...check eng. lite comes on when I start it (idle is low and it hesitates) ---I drive it and lite goes off after 4-5 miles(after a mile or two, the idle is actually kind of high when I stop, 1800RPM.)..---when lite goes off ,she runs smooth

book says coolant temp sensor or circuit
I cleaned the connector blade on the coolant temp sensor (was a little green) hoping for an easy fix....no luck..lol

Anyone know a simple way to diagnose...hate to buy one if not the real problem

I am assuming the computer thinks the engine is warm and is sending the wrong fuel/air mixture

I had put a new theromstat in a few weeks ago when I did timing belts---funny that this car temp gauge reads about 1/4 high when at temperature where all my others ran at exactly 1/2---its got plenty of heat and the elec fan comes on and off OK---was thinking I should go in and push needle up a little (I think I had done that with the gas gauge needle years ago on another Sub. and it holds the new position--anyone ever try this?.....I am a little anal about the gauge reading where it should..LOL)
thanks



#7 Caboobaroo

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Posted 22 January 2005 - 10:55 AM

you could possibly have a bad thermostat. I've heard of new ones "working" but they have a mechanical failure to them. They work but not properly. I've heard from some people here on the board that its because its an offname brand of thermostat and to use OEM but usually OEM parts like those happen to be aftermarket brands. Might try replacing it or if you had a shop do the work, the possibly could have put it in upside down?

#8 mudrat79

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Posted 22 January 2005 - 01:46 PM

As Skip stated The Coolant Temp Sensor is Sitting directly on top of the Return Inlet tube for the Radiator.....If you follow the Passenger side Rad. Hose to the engine, it Will bolt to this Housing.....The Coolant Temp Sensor will have a Plug with a Wire keeper holding it in place......This Sensor is 99% chance Bad.....Replace it , and You should Fire right up properly.....

If you don't, Check ECM again for codes.....??

If you continue to have Issues, Call me.....I'll talk you through some things......# is in my Sig.....

John

#9 Phaedras

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Posted 11 June 2005 - 01:01 AM

Sorry to revive this, but what kind of tool do you use to unbolt the sensor? Socket won't fit because of the connector and wire, and I see no way of jamming my 17mm wrench in there with enough room to turn.

#10 bgambino

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Posted 13 June 2005 - 07:56 PM

Sorry to revive this, but what kind of tool do you use to unbolt the sensor? Socket won't fit because of the connector and wire, and I see no way of jamming my 17mm wrench in there with enough room to turn.


I did use the 17 mm wrench--mine was not very tight




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