Before I tried to fix this, I got just a code 14. Now I'm getting a code 14 AND 15. This sucks.

Just for reference, here are the code explinations:

Code 14: Coolant sensor - High temperature fault
Code 15: Coolant sensor - Low temperature fault

So... like I said before, I was getting a code 14. Today, I tried to fix it by replacing the connector to the CTS because I broke it a while back and just never got around to fixing it.

I'm pretty sure my problem is the wiring. I connected to replacement harness wiring to the factory wiring through a little orange thing that came in the bag with the harness (not sure what it's called). However, the factory insulation was too big to fit into the tiny hole of the orange thing and I had to cut it off and expose the wires to get it to fit. That's where I think the problem is.

I basically just electrical taped the whole thing but I bet it came loose or something. However, I don't know what to do if that is this case.

Can someone please tell me how to hook up the wiring of the replacement harness to the factory wiring so I can finally fix this?

Here's a picture I made in paint to better illustrate what I am talking about (by the way, the replacement's wiring is noticeably thinner than the factory wiring... is this going to cause a problem too?):

 

You should generally use wire of the same gauge as what it is replacing. Where did you get the replacement harness from? Unless you disconnected the battery and cleared the codes, you will continue to flash both codes until the computer is reset.

 

The harness I obtained through a local Pontiac dealership and I bought it seperately from a kit that came with both the sensor and the harness (I already have a sensor and the kit was $46 versus $19 for just the harness).

I didn't disconnect the battery but I only had a code 14 at first. Now I'm getting 14 and 15 and the light is still coming on.

 

By the way, the part comes up at gmpartsdirect.com if that would help you at all.

The PN is 15306187.

 

Argh! I just looked it up through their catalog. It reads as "Speed Sensor Wiring Harness." Maybe that is the reason it's throwing a code?

 

That seems like a good possibilty.

 

Damn it. The guy at the dealership "assured" me it was the right part.

 

One more question. Are all these harness a universal fit? The harness I have now fits perfectly onto the CTS... just the wire is smaller then the factory wire.

 

Not all of them, to be honest about it. You would do better going to a junkyard and finding the harness you need there and it will be a lot cheaper.

 

There are literally NO thirdgens in any junkyards around here for some reason. My buddy and I have looked around and the few that are around have been picked pretty much bare.

Still, I'll have a look and see what I can find.


EDIT: By the way, thanks for your help, Trickster. I appreciate it.

 

As long as the connector physically fits the device, the connector shoudl work fine. The current level of the 5VDC signal in the CTS circuit is so small that the wire size just doesn't matter. However, since the voltage is relatively low, and the current is so small, good connectionos are essential. Forget about the crimp connectors supplied with the device. They are used as a temporary connection at best. Assemble up a line splice in the harness with a couple sleeves of heat shrink tubing, solder the connections, and shrink the insulation to fit. THAT is the way the factory intended splices to be done, and the way factory wiring harnesses are spliced at the factory (except for the heat shrink - in most cases they used tape).

Make sure you have the yellow on the 'B' terminal of the replacement connector, and the black wire on the 'A' terminal. You might also want to check for other grounds on your system, like the main ground node at the rear of the right head/intake area.

Other possibilities are poor connections at the ECM or stray AC voltage in the system being caused by a failing diode in the alternator rectifier bridge.

 

Incidentally, you can get a brand new connector from any place that has the Dorman/Motormite line, Standard Motor Products, or even NAPA. For about $4-5 you can have exactly what you need, new. The Dorman P/N is 85100.

 

If you pay atention to what you're buying, you could have gotten the harness for free.... most of the CTSs you buy for that car nowadays, will come with the harness in question, because the new CTS comes with a better plug than that stupid round thing the car came with originally (and the dealer will sell you duplicates of) that always falls apart, cevelops bad connections, and shorts together.

Another good example of something that should NOT be bought from GM, but rather from an aftermarket supplier. There are definitely things that MUST come from the dealer, things that SHOULD come from the dealer becausae they're the best place even though they're available elsewhere, things that COULD come from the dealer if you want, and things that SHOULD NEVER come from the dealer because they're overpriced or the aftermarket is just simply better. Unfortunately it can be hard to tell the difference sometimes, until you've made the wrong choice and found out the hard way.

 

Guess so. Well, lesson learned. I'm gonna try to solder the wires together when I get a chance. Thanks for the help.

 

I tried to reach you via PM, but it says you do not accept PMs.

Anyway, could you tell me which one is terminal "A" and which is terminal "B"? The sensor itself doesn't have any designation as to which is which.

 

It doesn't matter which is which. It's a variable resistance, totally polarity independent.

 

Oh, ok.

Thanks RB.

 

Have you even replaced the sensor yet? I was unclear of whether you did that or not.

First things first, clear the damn codes. Disconnect the battery for all of 30 seconds and reconnect it and see how it runs.

Next, if it still throws a code, check your wiring again.

If your wiring looks pretty good and the connections are solid (check with ohmmeter), replace the CTS itself..

 

Yes, it has been replaced since mid-April.

I cleared the codes a long time ago. I'm not getting 14 and 15 anymore; this question was asked in relation to another problem I'm having with a code 41 (right now the wires are connected via the "twist & tape" method and I believe the code might be being triggered by the bad wiring. I'm about to go solder the wires together now that I have obtained an iron and solder core).

 

hey, im getting trouble code 15 too! i was told taht i sohould check all the grounds and to also replace the sensor which i am going to do this afternoon. However, i was also told that if this does not work that i will have to trace the wire back to the pin itself. From reading and research i have found that the ecm pin that the coolant sensor connects to is pin 7. Hope that helps and anything will help me too.