I got a code 15 the other day, so I replaced my cooling temperature sensor. Engine wouldnt even start sometimes, would run great sometimes (within 5 minutes of each other). Still got a code 15 a couple times when it would run. So I replaced the coolant temp sensor with a new one (again), and just put a new computer in. Same problem, wont start at all sometimes, but if i can get it going it can run great. So I plugged WinALDL into it and it is reading 255 for the temp sensor (which it converts to -37 degrees). This is obviously wrong, so I completely disconnected the sensor and the readings on the computer did not change. I tested both wires to the sensor a number of times. Almost no resistance between the sensor and the computer on the yellow wire, ground on the black wire, +5 volts at the sensor (yellow wire) with the key turned. So what could be wrong? I've tried 3 cooling temperature sensors, 2 computers, and tested the wires a number of times? Any Ideas?

- Mike

 

Instead of pulling the sensor and replacing it again, temporarily install a 270 ohm resistor (common value) in place of the sensor, then see what WinALDL reads. It should be in the range of 185°F or so.

Which sensor are you replacing? (Location?)

 

I tried the resistor and it worked as expected, except that i noticed that i had to fold the leads (double them over) to even get a connection. Looking closer it seemed as if the connectors had been 'expanded', so I bent them back to something reaonable. Seems to make a good connection now, and everything works. Thanks for the reply.