2000 expedition o/d light flashing but still shift fine and has code p1746

The over drive light flashing is to tell you there is a problem with your transmission , an there are DTC's -diagnostic trouble codes stored . Take it an have the codes checked , you probably need a shift solenoid replaced .

run the fault codes to check for OD servo/solenoid problems or a problem TCM/ speed sensor unit.

Code means pressure control solenoids is open. If this is problem, you will experience harsh shifts like a bang into 2nd gear when accelerating hard. The PCM is not sensing the resistance the solenoid's coil should produce thus setting the code. You could have a bad connector, broken wire or bad solenoid. Please check or have everything checked before you start spending money. Remember, you did not fix the vehicle if you kept changing parts until it worked right. You merely spent too much money on a partial rebuild!

Generallry, codes P1746 and P1747 are both related to the EPC electrical circuits. These codes are only generted by and electrical fault. Inspect the wiring connector at the transmission. You may have have to use a mirror to inpsect the connector on the transmission itself. Disconnect both the transmission connector and the pcm connector and check the white/yellow wire (pin 11 at trans connector and pin 81 and PCM) check this wire for an open circuit, shorts to power or ground.
If the wiring checks ok the PCM driver for the epc has failed and the PCM will need to be replaced.

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CODE P1746 - EPC SOLENOID CIRCUIT MALFUNCTION. WHEN THIS CODE APPEARS THE ENGINE STARTED VECHICLE IN GEAR AND THE PCM DETECTED THE ELECTRONIC PRESSURE CONTROL EPC SOLENOID CIRCUIT INDICATED OPEN THIS FAULT CAN CAUSE HARSH ENGAGEMENTS AND SHIFTS. EPC MEAN ELECTRONIC PRESSURE SOLENOID.

With the light flashing ,codes are stored in the transmission control module . Have the codes check an this will tell you whats wrong . Probably a sensor or shift solenoid or line pressure solenoid .

My 2000 ford expedition XLT 4.2 L V8 overdrive lite is flashing as well took it in they said I need a new transmission so I are they can't put in a new overdrive thing my trucks rpm go high ones I'm over 45 it starts flashing and rpm go up but no power almost like it puts itself in neutral anyway I have to put in in drive 2 then switch back to drive to have power again as long as I stay under 42 miles an hour it drives fine over that speed overdrive light flashes and rpm are wakey lol I don't know anyone have a idea I don't want to put in a new transmission please help it's the only car my family has thank you

check for codes in trans thats what the light flashing means

need to check the wiring in the column to the od button it rubs the metal shorting it out in turn causing the blink with no mechanical problems

probably the vehcile speed sensor