I just bought a F150 with 103,000 on it. The engine is a 4.6. I get a P0605 code every now and then which doesnt effect performance. I erase the code and it doesnt appear again for maybe another 100 miles.

I suspect a loose connector but not sure. Looked up the code and it reads PCM READ ONLY MEMORY (ROM) ERROR. My question is what does the PCM operate? And wheres a good place to start troubleshooting?

 

The PCM runs the show. Generally if a tuner is installed it might cause issues. Either the memory in the computer, or low batter voltage, or a bad flashing of the computer. Bad or incomplete flashing.

The first thing I'd check is the battery and battery voltage.

 

Start your trouble shooting with grounds , then powers . The ECM operates the complete powertrain , engine and trans ( if auto ) . If all grounds and powers are good , no shorted sensors , you may need a new ECM .

 

Thanks for the info. I forgot to give the year of the truck which is a 2006. 1979 ford mentioned PCM and JWC mentioned ECM Are they the same thing in this vehicle? Also I have always worked on my own vehicles and only took them to a garage for big issues like rebuild transmission, but I have to admitt this is the first time I heard of a tuner, so can you tell me what this is? Because I read other post on this code and tuner was mentioned as a culprit. One other thing I dont know if they are tied intogether but the parking brake comes on often, and goes off by itself I checked the parking brake switch with a ohm meter and it checked good also checked the master cylinder fluid which is good wiggled wires to the master cylinder and the E brake and found nothing. There is also an after market remote starter installed on this truck which Im wondering could this be culprit?

 

The remote starter could be a suspect. I would check battery, then the ground for everything.

 

Got tired of looking at the check engine light after a year, and took the truck to the ford dealer and had the computer flashed and its been 2 weeks now and no check engine light

 

Hey. Check this out may be this would help you

Possible causes
- Engine Control Module (ECM) may be faulty
- ECM harness power supply circuit is open or shorted
- ECM harness ground circuit is open or shorted

Tech Notes
Try erasing the code first, if the light comes back ON you may have to replaced the ECM to repair the problem.

Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Engine may not start

P0605 Ford Description
The Engine Control Module (ECM) continuously monitors its own internal memory status, internal circuits, and output signals transmitted to the throttle actuator. This self-check insures that the ECM is functioning properly. If any malfunction is detected, the ECM sets the P0605 code and illuminates the MIL.

 

Been over a month and after taking the truck to the dealer to get reflased the code didnt return.