SES and Digital Temp Gauge
Thread Starter
Burning Brakes
Joined: Jun 2004
Posts: 919
Likes: 7
From: Aurora CO
SES and Digital Temp Gauge
For the past couple of days, about 5-10 minutes after I start the my 93, I get Service Engine Soon light. I watch the coolant temp on the digital gauge jump all around. It goes from 192 to 140 to 101 to 130 and so on and so forth. After a couple of minutes, the SES light goes off, the tempature gauge returns to normal. What do you think might be up with the car?
Pro
Joined: Feb 2006
Posts: 688
Likes: 0
From: Concord NC
Yea another problem diagnosed on my vette is that the WHOLE digidash is on the fritz. When im in park, the speedometer says im doing 25 MPH at 800 RPMs. New sensors and grounds need to be checked also a possible bad relay switch may be the culprit. Time to take the dash off and start checking
Best of luck with this.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
I would get the code or codes out of it. Ground on this circuit is shared with the TPS and MAT. If you get codes for two or more of these sensors, that's an easy way to determine that you have a bad ground.
Sensors are cheap enough - about 9 Bucks - but it may still be the PCM or wiring. Disconnect and verify the 5 volt reference on the Yellow Wire. Jumper the pins and that should give you about 300 on the Digital Display. Clear any 14 or 15 Codes after you do these tests. You can take the new one and check it's resistance cold and compare that to the resistance of the one installed after it's sat overnight. Should be close. You can also just plug the new one in and if the problem is gone, then replace it. If not and the wiring checks out, it's the PCM.
Sensors are cheap enough - about 9 Bucks - but it may still be the PCM or wiring. Disconnect and verify the 5 volt reference on the Yellow Wire. Jumper the pins and that should give you about 300 on the Digital Display. Clear any 14 or 15 Codes after you do these tests. You can take the new one and check it's resistance cold and compare that to the resistance of the one installed after it's sat overnight. Should be close. You can also just plug the new one in and if the problem is gone, then replace it. If not and the wiring checks out, it's the PCM.
