I have a check engine light on, when engine is running! The codes are 117&118 which is coolant temperture high&low circuit input! I've installed a new thermostat , housing and sensor but the light is still on. With the sensor plugged in the fan will not start until the engine is almost to the HOT with the sensor unplugged the fan comes on when the engine is started! This tells me that the circuit is a normally open circuit when the sensor closes the fan comes on, is this correct? Why is the fan running with the sensor unplugged? unplugged?
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replace the coolant sensor unit as that is where the ECM gets the signal from to activate the relay that turns on the fan
check all fuses 2 or more in that circuit have the system checked by an accredited auto electrician before you do any thing so drastic
P0108 (M) MAP Sensor Voltage Too High, P0118 (M) ECT Sensor Voltage Too High Engine coolant temperture sensor input above the
maximum acceptable voltage, P0123 (M) Throttle Positon Sensor Voltage High Throttle position sensor input above the maximum
acceptable voltage range, P0522 Oil Pressure Sensor Low Oil pressure sensor input below acceptable voltage. Sounds like you have an electrical problem, either computer failure or bad sensors. It's hard to believe that you gained so many sensors just from replacing the cylinder head. Disconnect your battery for one minute, then reconnect. Try driving it down the road.
the "sensor " near the thermostat should have 2 ,3 or 4 wires to it
if it only has one wire , that is the temp gauge sender unit and not the coolant sensor the coolant temp sensor reports to the ecm and that unit then switches on the fan relay that spins the fan
if you unplug the coolant sensor and the fan starts to run you have a serious coolant temp sensor circuit problem
take it to an accredited service center and have it sorted
The car runs fine after it warms up? Is it running with the check engine light off? But it does come on with the key before the engine is started? If the coolant temperture senser is bad ( or disconnected someway) the check engine light will be on but the car might run OK at normal operating tempertures. Have the car checked for codes. It's OBDI so you might have to find a service provider that can ceck the codes on this pre OBDII car. If it turly runs good at normal operating tempertures and the transmission is'nt low on fluild then the coolant senser does'nt always turn the check engine light on if it's bad and still reading something but wrong. Truly running good and the coolant is full ( all the way). chage the senser and see what happens as thier cheap and easy to change with commn hand tools.
The radiator cooling fan relay in ford Tempo gl has been integrated into the CCRM (Constant Control Relay Module) this is the black box fixed to the left strut tower with the big cable harness on it.
This relay box is commanded by the PCM (Powertrain Control Module) it´s linked to every sensor in the car. (It's located behind the fuse panel next to the steering column.
The PCM supervises various conditions, including the signal that the ECT (Engine Coolant Temperature) sensor sends and power up the Fan Relay into CCRM to activate the Cooling Fan. -------------This should help.Thanks.Helpmech.
When my 94 Regal GS frequently wouldn't start for 30 minutes to an hour
after being driven, it was the crankshaft positioning sensor that
needed to be replaced. I also replaced the harmonic balance pulley. The car ran more smoothly and started everytime.
Check the coolant temperature with the car stopped. At idle with the hood up keep the thermometer in the coolant. Confirm if the coolant is not overheating but the engine is!!
Run the A/C keeping the thermometer in the coolant and allow the fan to kick on.
If with the A/C on the engine doesn't overheat then it confirms that the low speed on the fan motor is not working. Read the description of the Taurus where the low speed is used for normal operation when temperature is required but the high speed is activated when the A/C is on. The circuit is simple.
In your case the low speed has to be activated for the A/C to go into the high speed. The fact that the high speed is working and low speed is not indicates the low speed of the fan is defective.
Other problems such as the thermostat or plugged cooling system(radiator clogged) could be the root problem!