code 15? What to check for.
Thread Starter
Junior Member
Joined: Mar 2001
Posts: 39
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From: Detroit
code 15? What to check for.
I got code 15 today and was wondering where to start checking. code 15 says low temp at coolant sensor (correct me if i'm wrong).what is the most common problem related to code 15. any help would be appreciated.
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1985 Camaro Iroc Z
305 Tuned Port Injected
Planning for a 350 swap soon!!!
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1985 Camaro Iroc Z
305 Tuned Port Injected
Planning for a 350 swap soon!!!
Moderator
Joined: Jan 2000
Posts: 19,679
Likes: 316
Motown,
The "Code 15" is for an impossibly low temperature reading from the CTS, as you describe. Usually this means either a failed or disconnected CTS. The CTS that signals the ECM on your TPI is located at the front of the intake manifold, in the coolant crossover passage.
It is just visible at the extreme lower left edge of the photo. There are actually two sensors located there. They are the CTS and cold start injector control. You are looking for the one with a two-wire connector with a yellow and a black wire.
I'm not sure what your source is, but if you want a fairly complete listing of DTCs, check this file:
GM Error Codes.pdf
You'll need Adobe Acrobat Reader to view/print the file.
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Later,
Vader
------------------
"Get UP - Drop the bombshell!"
Adobe Acrobat Reader
[This message has been edited by Vader (edited August 18, 2001).]
The "Code 15" is for an impossibly low temperature reading from the CTS, as you describe. Usually this means either a failed or disconnected CTS. The CTS that signals the ECM on your TPI is located at the front of the intake manifold, in the coolant crossover passage.
It is just visible at the extreme lower left edge of the photo. There are actually two sensors located there. They are the CTS and cold start injector control. You are looking for the one with a two-wire connector with a yellow and a black wire.
I'm not sure what your source is, but if you want a fairly complete listing of DTCs, check this file:
GM Error Codes.pdf
You'll need Adobe Acrobat Reader to view/print the file.
------------------
Later,
Vader
------------------
"Get UP - Drop the bombshell!"
Adobe Acrobat Reader
[This message has been edited by Vader (edited August 18, 2001).]
Thread Starter
Junior Member
Joined: Mar 2001
Posts: 39
Likes: 0
From: Detroit
Thanks for the link Vader.
In the morning im going to check the wires going to the sensor because a while back i posted a problem and you told me to check the yellow wire and sure enough that solved the problem.
But anyways if all the wiring looks good how do you test to see if the sensor has failed. I've been told to test the resistence but im not exactly sure how could someone please explain that process to me. Thanks
------------------
1985 Camaro Iroc Z
305 Tuned Port Injected
Planning for a 350 swap soon!!!
In the morning im going to check the wires going to the sensor because a while back i posted a problem and you told me to check the yellow wire and sure enough that solved the problem.
But anyways if all the wiring looks good how do you test to see if the sensor has failed. I've been told to test the resistence but im not exactly sure how could someone please explain that process to me. Thanks
------------------
1985 Camaro Iroc Z
305 Tuned Port Injected
Planning for a 350 swap soon!!!
Moderator
Joined: Jan 2000
Posts: 19,679
Likes: 316
Motown,
Almost all GM temperature sensors use a resistance element to signal temperature to the controls. As the temperature increases, the resistance decreases. When the temperature hits 285°F, the resistance is effectively zero ohms. At -40°F, the resistance is about 100,000 ohms. At that poointm the ECM refuses to believe that the sensort is accurate and sets the error code. Obviously, a broken connection would present a lot more than 100,000 ohms, and cause the same error.
The resistances ar various temperatures should be as follws:
Test the resistance with an ohmmeter and compare it to the approximate temperature at the sensor tip. A cold engine at 75°F air temperature should cause a resistance of around 3,000 ohms. If your sensor isn't dead-on accurate with the table, it isn't a big problem. As long as it is close, it should be fine. Any major problems should be readily apparent with the meter.
In case your sensor is failing, a replacement can usually be found at most auto parts stores for about ten bucks. Just use a good thread sealant on the new sensor if you get to that point (Loctite PST is a favorite of mine).
------------------
Later,
Vader
------------------
"Get UP - Drop the bombshell!"
Adobe Acrobat Reader
Almost all GM temperature sensors use a resistance element to signal temperature to the controls. As the temperature increases, the resistance decreases. When the temperature hits 285°F, the resistance is effectively zero ohms. At -40°F, the resistance is about 100,000 ohms. At that poointm the ECM refuses to believe that the sensort is accurate and sets the error code. Obviously, a broken connection would present a lot more than 100,000 ohms, and cause the same error.
The resistances ar various temperatures should be as follws:
Test the resistance with an ohmmeter and compare it to the approximate temperature at the sensor tip. A cold engine at 75°F air temperature should cause a resistance of around 3,000 ohms. If your sensor isn't dead-on accurate with the table, it isn't a big problem. As long as it is close, it should be fine. Any major problems should be readily apparent with the meter.
In case your sensor is failing, a replacement can usually be found at most auto parts stores for about ten bucks. Just use a good thread sealant on the new sensor if you get to that point (Loctite PST is a favorite of mine).
------------------
Later,
Vader
------------------
"Get UP - Drop the bombshell!"
Adobe Acrobat Reader
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