codes P0117; P0125; P0711 ?

[nmcarguy]

I have a 1998 SW2 I'm working on and have these multiple codes. P0117 is "engine coolant temp circuit low input". I changed the Temp Sensor 2 months ago with an AutoZone part and now the code is back. The car wont start unless I hold accellerator to the floor and then runs ruff. I noticed someone posted to use only a true Saturn Dealer Temp Sensor, could this be the problem here?

Next codes are P0125 "insufficient coolant temp for closed loop fuel control" & P0711 "transmission fluid temp sensor circuit range/Performance" - this one really worries me. These 2 codes were not present last time when I replaced the temp sensor so I'm affraid I got more of a problem.

Any help will be appreciated.

Thanks.

[mysatilac]

if you bought the ECT (Engine Coolant Temp) Sensor from an auto parts store then yes, the part has now probably cracked like the original because it was a plastic composite tip instead of the new brass tip sensor,

The other coolant temp code was probably thrown because the computer is getting a bad reading from this sensor,
Replace with this one from saturnparts
It will outlast your car,

The tranny fluid code, I dont know, Check the condition of the fluid and get back to us, replace this sensor and see if it throws the code again, or take it by a shop to see what they say,

[nmcarguy]

Thanks, I'll get back to you.

[sierrap615]

its possible that the trans temp code was caused by ECT, but don't count on it.

replace the ECT, check the connectior for gunk that leaked from the bad sensor. if you have a multimeter, check for a galvanic charge(SP?) in the coolent, set on voltage place one lead in the coolant and the other to ground. techinally, above 0.500 volts is bad, in my mind, i wouldn't even give it that much. if you find a galvanic charge, flush the coolant.

[mysatilac]

galvanic charge, Never knew that, now I do,
Thanks to the ever flowing fountain of knowlage, Sierrap615!

Sierrap's fan club --->

[sierrap615]

its a sign of a high acid level in the coolant IIRC, dissimilar metals generate a electric charge, this is how your O2 sensor works too. as a kid i even had a small LCD clock powered by the citric acid in two oranges(i wish i still had that thing)

i normally wouldn't consider this as a possible cause of failure but with the extra codes and the short failure time(2 months) i just want to rule out one more thing.

[nmcarguy]

Hmmmm.. well the galvanic charge was only 0.268 so I disconnected the battery and unplugged the wires to the ECT sensor and it was pretty clean but I used brake cleaner on the plug just to be sure. Lo and behold, when I put battery back in the car started and as the diconnect cleared the codes..... the engine lite was off. I drove the car and so far not engine lite. I notice the wires to the ECT are a little taught so maybe the plug just lost connection. I'll try to open the wire loom and release some tension on the wire.

I'll let you know if any codes come back as the P0711 trany code still has me concerned. I'm leaving in the AZ temp sensor as it seems to be OK but if problem reoccurs that is where I'll go next.

Thanks for the help.

[mysatilac]

Not a problem, you can check to see if the ECT is good or not by testing the resistance,
Use a multimeter set to Ohms on the two posts on the ECT

Originally Posted by MySatilac

Here are the resistances for the ECTS or IAT in various tempertures
-20 degrees F________39K-53K OHMs
0 degrees F__________21K-27K OHMs
60 degrees F_________3.9K-4.5K OHMs
120 degrees F________1.0K-1.1K OHMs
160 degrees F________430-480 OHMs
200 degrees F________215-235 OHMs

[sierrap615]

if the wiring is bad the connectior itself and a few inches of wire are sold in a repair kit. part #12117087 i think