Hello all, looking for some help. I have a trouble code 624 epc failure with engine misfire condition. I was returning from a weekend trip when this occurred and had to drive about 150 miles in this condition. Could I have hurt the trans driving home? Trans temps were normal.

When we returned home I found a loose battery ground, and after cleaning and tightening connections all symptoms have gone away.

Is there two different conditions of this 624 code? one that causes a closed loop (low line pressure) and an open loop (high line pressure)?



Thank you for any help with this.
Robert Pearson

 

There are two 624 codes, one is from the Key On Engine Off self test and the other is from the Continuous Memory stored code from while running on the road.

You did not say what the codes were generated from so I am going to guess that they were from the Continuous Memory stored codes.

DTCs 624 indicate an Electronic Pressure Control (EPC) circuit failure.
Possible causes
-- Damaged harness connector.
-- Damaged EPC solenoid.
-- Damaged TR sensor.
-- Intermittent harness continuity.
-- Damaged PCM connector pins.

When the EPC is loses connection from the PCM the pressure will go to maximum to prevent damaged to the E4OD.
So I do not think it hurt the E4OD but I would look at the TR sensor.
Was it raining when you were driving?

 

Thank you for the reply. Yes it did occur while driving and yes it was a CM code. It was not raining on the trip.
I have read that there is an open or closed loop epc condition with this code. the closed loop condition causes a low line pressure and the open causes a high line pressure condition. Any experience or can confirm these two scenarios?

 

I think you are talking about open circuit and short circuit and not loop.

Here is a page from the E4OD manual.

/

 

Thank you subford, yes this is it exactly. how would i determine which failure i have? I did have the major misfire condition so i would guess i had the "closed circuit" low pressure. If this is the case would it still go into a maximum pressure "limp mode".
Trying to determine if i hurt the trans with the travel back in this condition.

Thank you again, i appreciate your help with this.

 

No if it has a short circuit to ground it be like you are in "N" (max slipping) and no it would not go into the so called limp mode.

Here is a link to Test "E" as noted in the code chart.
https://www.ford-trucks.com/g/album/7426647

/

 

Thank you subford this is very helpful. Do i understand this correctly that if it was a short circuit condition i would experience more slippage or non movement of the vehicle?

 

Yes you understand it correctly. A short circuit to ground condition you would experience more slippage or non movement of the vehicle.



/

 

Thank you subford for your help. Although new to this group I have seen that you support many of these ford communities and appreciate your helpfulness to those of us in need.
I was concerned as to weather or not is hurt this trans and believe i may have been lucky in this instance.

Anything with this code 624 that I should continue to monitor or need to watch out for?

Once the battery ground was fixed i have not experienced any more symptoms.

 

The 624 code in CM will last for 60 or more start-up unless you clear it so it needs to be cleared so you will know if you get a new code.

I do not see how the battery ground would have caused this but stranger things have happened with a loss of battery ground.
With it running the chassis battery should have been running in parallel (+ side) with the coach battery(s) and they should have supplied a good ground.

 

Originally both positive and negative were loose, must have forgoten to tighten after winter storage. Sorry i did not communicate that correctly on original post. Thank you again for all your help.