Confused... P0118

Im at 118k now, had my oil done at 116k by BMW, coolant flush and fill at 116k by BMW and a LI inspection at 116k by BMW. 2001 330ci Auto/Step.

I searched before posting and my problems, although similar are not related to OP's in other threads. (outside of similar code)

Moving on, I noticed I was throwing a P0118 (with my temp gauge always buried in the red and giving me a read out of -128, Occasionally it would right itself and give me a proper read out of anything between 90-96 when the engine warmed and anything between 30-50-70 when I started it up and was building temp/getting up to op temp... Anyways I decided that I would do a full coolant overhaul. I replaced upper/lower hoses, expansion tank, thermostat, water pump, and temp sensors in tank and hoses, oh and I picked up a K&N since my dry filter needed to be replaced.

P0118 - Engine Coolant Temp (ECT) Circuit High Input MOD$12

Bled/rebled/filled/checked oil and drove ~15 miles. Erased code... Yada yada... Great install, went as planned and everything worked, for about 10 miles and while I drove to work.
Anyways I start my car tonight after work and it starts great, idles fine and shows it at 34*C, warms fine and sits at 90-96, well before I got on the tollway, boom, buried in the red and showing -128 again... WTF? I scan when I get home and Im throwing P0118 all over again. New Thermostat/housing/hoses/tank/sensors... Did I miss something? I noticed that it's a "high electrical input" error. Am I having an electrical issue at this point? I would like to fix it myself but am half tempted to take it to the stealership and see what they say.

What do the gods think? Electrical? Faulty thermostat? Bad sensors? I really wanted to have this cleared up after the whole walk through.

I've read and googled anything from faulty sensors, faulty thermos, faulty gauges to bad wiring and electronics/ecu/vanos... I just dont know what to think and Im trying to save myself from the $500 LII @ BMW although I think it'd be a good idea to do before 120k regardless. Ugh... Decisions decisions.

I am stumped.

Originally Posted by TampaE46

Im at 118k now, had my oil done at 116k by BMW, coolant flush and fill at 116k by BMW and a LI inspection at 116k by BMW. 2001 330ci Auto/Step.

I searched before posting and my problems, although similar are not related to OP's in other threads. (outside of similar code)

Moving on, I noticed I was throwing a P0118 (with my temp gauge always buried in the red and giving me a read out of -128, Occasionally it would right itself and give me a proper read out of anything between 90-96 when the engine warmed and anything between 30-50-70 when I started it up and was building temp/getting up to op temp... Anyways I decided that I would do a full coolant overhaul. I replaced upper/lower hoses, expansion tank, thermostat, water pump, and temp sensors in tank and hoses, oh and I picked up a K&N since my dry filter needed to be replaced.

Bled/rebled/filled/checked oil and drove ~15 miles. Erased code... Yada yada... Great install, went as planned and everything worked, for about 10 miles and while I drove to work.
Anyways I start my car tonight after work and it starts great, idles fine and shows it at 34*C, warms fine and sits at 90-96, well before I got on the tollway, boom, buried in the red and showing -128 again... WTF? I scan when I get home and Im throwing P0118 all over again. New Thermostat/housing/hoses/tank/sensors... Did I miss something? I noticed that it's a "high electrical input" error. Am I having an electrical issue at this point? I would like to fix it myself but am half tempted to take it to the stealership and see what they say.

What do the gods think? Electrical? Faulty thermostat? Bad sensors? I really wanted to have this cleared up after the whole walk through.

I've read and googled anything from faulty sensors, faulty thermos, faulty gauges to bad wiring and electronics/ecu/vanos... I just dont know what to think and Im trying to save myself from the $500 LII @ BMW although I think it'd be a good idea to do before 120k regardless. Ugh... Decisions decisions.

I am stumped.

http replace
xxxx://www.obd-codes.com/p0118

CausesA code P0118 may mean that one or more of the following has happened:

A bad connection at the sensor = check plug
An open in the ground circuit between the ECT sensor and the PCM =broken ground cable

A short in the voltage feed between the sensor and the PCM=a power cable hitting ground
A bad PCM (less likely) = your fk just kidding
A bad temperature sensor (shorted internally)=if integrated in thermostat thermostat might be oppening correctlly but sensor is reading a different temp.

if it goes all the way to the red area but the car doesnt over heat that tells me thermostat is fine! however the gage going all the way up tells me either your sensor is bad or the feedback cable hitting ground!!
a sensor works by adjusting its resistance!
on the pic. where am touching both probes the resistance is .1 which mean there is direct contact= strong signal
on the other pic. you see a big number 7.51= less contact the higher the number the less the contact that is making!!
so having said that your feedback adjusts as the water changes temperature so if your thermostat is not over heating your car either the sensor or cables are acting up! turn on the car and try moving the wires but have someone check d cluster while u move it!
am not sure if you have a 2, 3 wire sensor or 4 if you have a 2 wire sensor it works with ground only see sketch i'll load it in a bit my pc is acting up!!

Did you ever get this issue resolved? I have the same problem but have not begun replacing parts yet. The issue points to the coolant sensor in the head but it appears you may have to remove the intake manifold to replace. Hope I can gain access to it by removing the cabin filter housing and side panel. Amazing so much labor to replace a $20 sensor.