KyleW707

97 z28, iat sensor and coolant temp sensor were both reading -40 but no codes. Replaced both and no change. Tested voltage and cts is reading 5+, iat read zero. Replaced the iat pigtail and now it's reading right. Cts still reading -40 but showing 5+ volts. Tried to check resistance (ohm) in a cup of water and it read 3.xxk which is between 58-69F which was about right according to the thermometer I had in the water. Am I missing something on testing resistance in the cts?? No problems that are typically related to a bad cts besides plugs are fouling quickly. Car starts up whether I have the cts plugged it or not, and no change when plugging or unplugging while running. Also replaced cts pigtail even though it was reading right and still reads 5+ volts. Anyone have any ideas?

KyleW707

The pin for cts is #25 in the grey harness connector. Is there I way I can test that?

shbox

To check a wire, you disconnect it at both ends and ohm it end to end.

Have you also checked the ground that goes to the sensor?

KyleW707

Do you know which one is the ground for it? The chart I looked at only said "sensor ground" and there were several different ones

KyleW707

So to test resistance I need to put a lead on #25 and the other on one of the pigtail terminals?

KyleW707

Figured it out. 20amp engine sensor fuse was blown