Resolved 98 Spyder GST P0115 and P0325 check engine codes just popped up

[and1chewy]

i have had a couple check engine codes pop up recently. a p0115 ( coolant temp sensor malfunction) a p0325 (engine knock sensor malfunction) and a p1105 ( a dsm specific fuel pressure solenoid malfunction). Basically my question is are these codes completely unrelated? i think the knock sensor and the fuel pressure soleniod could possible be related but i dont think that the coolant temp sensor would be related to any of the above. i have read that the coolant temp code could be caused by a bad pcm but the car is actually running fine at the moment. I just ran the codes havent dug into anything as far as freyed wires or looked at any connections as of yet i was going to start at the fuel pressure solenoid issue first as i think that could be causing the knock issue as well. thanks for the info. the car is a 98 gst spyder.

 

[Mrdocprofessor]

the coolant temp might be unrelated but if your fuel pressure is low you will get knock

 

[Paulie D]

It is possible for a bad pcm to give 1 or all 3 of the codes, but is very uncommon. If all 3 codes came on at the same time, there's a high probability that they're all related. The coolant sensor could be reading incorrectly and telling the computer that its too warm, so its not supplying enough fuel or too much fuel which would cause the fuel pressure code along with the knocking code. It's hard to say exactly what the problem is if you can't see what the sensors are reading. Do you know anyone with a snap on scan tool or anything so you can get some graphs of whats happening?

 

[99talongsx]

start with coolant sensor relatively inexpensive and easy to fix

 

[Geier]

You need a logger or at least some sort of scan tool that will tell you what values your ECU is seeing. Your coolant temp should rise to about 185-195. A bad coolant temp sensor will sometimes prevent a car from even starting. The knock sensor and FPRS will more than likely be related to the coolant temp sensor.

However, with my 3000GT, I did have to replace the FPRS in order to pass emissions. It was a dealer only part too BTW.

 

[and1chewy]

i cleared the codes that day only one came back on after about 20 miles (coolant temp sensor) so i cleared it again drove it came back on. went to the parts store and your right relatively inexpensive $16 my cost $25 list i believe. took my intake tube off reached down to unplug the sensor and it just fell off aprently somehow it unplugged itself or it never clicked in and over time wiggled itself off. so i plugged it back in have been driving about 200 miles no check engine light. kinda stupid but no way of telling till i looked down there.