Low Coolant and High Idle RPM's

[gamefanatic]

Hey all. I am having some troubles with my 97 Seville STS.
Last week my dad came home from a short trip to the store. On his way home the engine started accellerating on it's own to around 3000 rpm's. When he stopped in the driveway and the radiator busted open at that plastic tank. I am not sure if the 2 issues are linked, but now that I have replaced the radiator and filled the system with coolant we are still getting the "Low Coolant Level" message and once the engine get's about normal tempratures the engine steadily starts to increase RPM's to about 2800-3000 and stays around that range.

Anyone have any idea's? The coolant level is good, but we are still getting the message that it's not. Maybe the sensor is bad? If so would that make the engine idle high?

TIA!

[submariner409]

Go back to the main Seville thread page and look at the top 4 or 5 threads: the "stickys". There is one titled "How to pull codes". It will tell you how to use the car's built-in code scanner/reader system to inform you of problems. Read the entire thread, practice pulling the DTC's (Diagnostic trouble Codes), write them down noting whether each is Current or History. Then go back to the thread and click on the link with "obd2" in the URL. Then click on the lines for P, B, C, and U codes to decipher each.

C'mon back !!! Welcome Aboard !!!!

[Ranger]

The coolant level is good, but we are still getting the message that it's not. Maybe the sensor is bad? If so would that make the engine idle high?

Yes, most likely the sensor. It's in the surge tank and not serviceable. You must change the tank.

No, it won't cause a high idle.

[gamefanatic]

Hey guys. Thank's for the quick response. Unfortunately there are no codes to pull... I did have the inital ones telling me the battery was disconnected P0603 and KAM, but nothing else. I have cleared the codes and nothing has popped up.

[00 Deville]

Since you don't have any codes... try disconnecting the battery for 15 minutes then reconnecting. Maybe that will reset whatever is stuck on the high idle.

A couple of CF members have reported that they were able to "fix" the low coolant message by taking a long screwdriver and pushing the float up and down several times inside the surge tank.

[gamefanatic]

Sorry I did have the historical codes written down before I cleared everything. Keep in mind after clearning the "historical" codes nothing has returned:

PCM:
P0122 - Throttle Position (TP) Sensor Circuit Low Voltage (possible)
P0603 - Control Module Long Term Memory Reset

IPC:
B1552 - Keep Alive Memory (KAM) Error

SDM:
B1136 - Discr. Sensor Open or Short to Voltage

TCS:
C1255 - EBCM Internal Malfunction

PZM:
B1552 - Keep Alive Memory (KAM) Error
B1558 - BCM EPROM Checksum Error

IRC:
B1771 - Cassette tape slow
U1064 - Loss of Communications with DIM

MMM:
B2144 - Left Front Mirror Vertical Position Sensor Circuit Low

[gamefanatic]

Well my brother came over with his snap-on scanner and plugged it in. Not sure what changed but all of a sudden everything was working correctly. All of a sudden the idle was working again. He was able set the idle up and down with no problems. Grr...

Oh well, thanks for the tip on the coolant tank I will try to see if there is a problem with the sensor or just replace the tank with the one from my parts car...

BTW - I had disconnected the battery both before I started the radiator repair and couple of times trying to solve this issue. Unfortunately that didn't work this go around.

[N*Caddy]

Probably is a temprary "fix".
P0122 - Throttle Position (TP) Sensor Circuit Low Voltage (possible)
This is EXACTLY your problem.

[gamefanatic]

Thank's N*Caddy. That's what I was leaning towards. Even though the issue was so inter-twined with the temperature. Maybe they have something to do with each other...

I am going to finish flushing the system tomorrow, if the problem shows up again I will be sure to replace my TPS as well. I did do some cleaning around there so that might have loosened it...