Last nite i was driving around and the check engine light came on so i went through the scanmaster and noticed the dtc was going from 15 to 45 and 15 to 45 and keeps doing it. I also noticed that the air feul ratio gage was staying in the green. Any ideas ?? Still seems to run great.

 

Here's a good link from Injuneer:

http://members.aol.com/InjuneerZZ/Sc....htm#step%2026

Code 15 - Coolant temp sensor, signal voltage high, low temperature
Code 45 - Bank 1 (left) O2 sensor, rich

 

opps its 15 and 43 not 45 and the check engine light comes on then off then on then off ??????????? hey thanks for the web site but i`m still confused.
43 = Knock sensor circuit so now what ?????????

 

The ScanMaster reads the stored DTC codes and scans through them repeatedly, as long as your are displaying the DTC screen. If you only had one code, it would only show one code. If you have ten codes, it will scroll through all 10 codes and then repeat as long as that the item you've selected.

You need to try clearing the codes. ScanMaster shows you both the "active" codes and the "stored" codes, with no way to differentiate which is which. See if either or both of those come back when the SES light comes on. Key off, pull the "PCM BAT" fuse for 30 seconds.

DTC 43 means either the nock sensor or the wiring is bad. Key on pull the harness connector off the knock sensor. Measure voltage from the single wire on the harness to the engine block. Should read 5V. If you have 5V, wire is OK. If not, wire is bad.

With harness still unhooked, measure the resistance between the single pin on the sensor and the engine block. Should read 4,500ohms +/-1,000ohms. Between 3,500-5,500ohms the KS is good, outside those limits its bad.

Then reconnect the harness wire and probe voltage from the wire to the block.... should be 2.5V +/-1.0V. If votage is between 1.5-3.5V, SES light will not be on. Outside those limits the SES light comes on.

DTC 15 indicates the coolant temp sensor in the water pump housing, or the wiring is faulty. The sensor shuold produce a specfic resistance at a specific temperature. Wiring harness off, probe the two contacts on the sensor. Measure the resistance. Compare the resistance vs. temperature to the table shown in my ScanMaster writeup, linked above.

 

WOW thank you for all the info and great web site its now in my favorites
ok now i just have 43 code up and i checked wireing and is good so it must be the knock sensor on the block it self right ?? if so can i get a couple from any auto parts or should i stick with gm ??? But dealers are not opened till tuesday
oh ya i forgot to mention this is a 95 396 impala
also the check engine light keeps comeing on for about a minite than go`s off for a minite then come on and keeps doing it ????????? when the light comes on the air feul ratio gage go`s to the green ?????"

 

On the sensor to block test i got a little under the low limit 3,400ohms
bad sensor ?? are these cheap ???

 

Check Shoebox's website, he has the parts list and prices there.

http://shbox.com/1/4th_gen_tech1.html

 

Hey thanks again i took the knock sensors off my other impala and put them on and i`m good to go