PCM reprogramming

[Fadi]

Hello my friends , I have Ford fusion energi 2013 , I had an electric problem with my car any and the mechanic fixed it , and he said that he reprogrammed the PCM , after I took the car , the maileage dropped from 4.4 L/km to around 5.5 L/km , and I feel that there is something wrong with the acceleration , anyway I took it 3 mechanicals and all of them confirmed that there is nothing wrong with the car and it's in perfect condition .

My question , does reporgarming the PCM , cause this ? As I have heard that when you reprogram the PCM , the need 1000 mile to learn your driving style again , is that correct ?

 

[KrisZ]

Sounds more like your mechanic reset the PCM.
If the PCM was actually reprogrammed (which I highly doubt), then there is nothing for it to learn, it will operate under the new parameters that were programmed in.

 

[Fadi]

Thank you , and resetting it can affect car mileage ?

 

[MolaKule]

Originally Posted By: Fadi
Thank you , and resetting it can affect car mileage ?


Until the car is driven and the PCM learns your driving habits again, then yes it may lower gas mileage than before.

In most PCM's there is a default subroutine that kicks in until the PCM has learned again.

 

[The Critic]

Originally Posted By: KrisZ
Sounds more like your mechanic reset the PCM.
If the PCM was actually reprogrammed (which I highly doubt), then there is nothing for it to learn, it will operate under the new parameters that were programmed in.


PCM programming is a very common procedure nowadays. Many repairs require updated software or coding. A J2534 interface is the most common method used. Dealers use IDS for Ford and some independents may have invested in that tool as well.

 

[Bottom_Feeder]

Originally Posted By: MolaKule
... until the PCM has learned again.

 

[spasm3]

Unless you are calculating fuel mileage by tank and mileage and averaging several tanks, you really don't know what your mileage is. I don't think any of the dashboard fuel mileage numbers are very accurate. It the pcm was reset, it will take 60-70 miles or so for the pcm to settle in, measure fuel mileage after this distance.

 

[The_Jeff]

Remember also this is a hybrid, so it might be playing with its own battery to "get to know it" after the reset or reflash. Give it time.

 

[hpb]

I'm hoping you mean 5.5 litres per 100km...

 

[Fadi]

Originally Posted By: hpb
I'm hoping you mean 5.5 litres per 100km...


Yes , 5.5 liters per 100km

 

[Fadi]

I will perform a hard reset again by pull the negative cable , the technician drove the car aggressively after he reset it so maybe it learned this bad habit