Check Engine light on

The problem is diagnostic fault codes never say a part is bad or needs to be replaced. They only indicate the circuit that needs further diagnosis. When a part is referenced in a code, that part is actually the cause of it about half of the time. First you have to check the wiring and do some voltage tests.

Normally coolant temperature sensors have an extremely low failure rate, but Ford did have a lot of trouble with theirs in the early to mid 1990's. If you replaced one with a single wire, that is for the dash gauge and is not related to the fault code. It is the two-wire sensor that is for the Engine Computer.

Back-probe through the rubber seals next to each wire to take the voltage readings. The ignition switch must be on and the sensor must be plugged in for the readings to be valid. If you find 5.0 volts on one or both wires, there is a break that we will need to find.