Hi all, We have a 2001 F150 Supercrew (5.4L/V8, automatic) that had a problem with the P0300 misfire. It had a ruff idle when cold, but ran great after being warmed up. I had it in to a mechanic a year ago to fix a different problem and he told me that he thought it was a vacuum leak. My son found that the PCV elbow in the back of the engine had broken. We fixed that but the code or the ruff idle didn't go away. We couldn't find any other leak without a smoke machine. Anyway, the truck was parked in the driveway for many months while I tried to save up money to have it fixed. Can't smog a car here in CA with the check engine light on. Well, a week ago, I went out to move the truck and the battery was dead (we have a very small parasitic leak that I can't find). Anyway, we charged the battery, and then had the usual nightmare with the PATS system allowing us to start the truck. Once we got the truck starting we noticed the check engine light was off but the ABS light was on?? Checked and found out you can smog a car with an ABS light on. Drove the truck to a Pass or Don't pay station & they said I needed 1 last sensor to set and then they could test it. When I drove the truck to the smog place, the truck did not idle bad or run ruff at all. So i drove the thing all around, about 100 miles, and took it back to the smog place and it passed. Now, when I put my scanner on it says that the truck has a pending P0300 code, and it also has the following codes: B1342, C1222, C1115, U3FFF ,P1000. I know the first 3 codes are related to the ABS system but not sure what to check? I should also mention that this truck got hit by another car in the front right tire, but that was 4 years ago and the ABS code never came on until last week. I thought I did detect a slight brake pedal pulse a couple of times when driving it to/back to the smog place. What is bizarre is the truck ran great , before the battery died, with the exception of the ruff idle, which was/is probably due to the vacuum leak. It's weird that it would now have a ABS problem when it has been sitting for months.I should also mention that my son reminded me that for a few months last year, the rear window on the truck would leak and the inside of the cab would fill with moisture (enough to from condensation to the inside of the windshield).That was during the winter/rainy months. We had the rear window seal repaired before summer started ans so far haven't detected any leaks, but we won't know for sure until we have a few good rainstorms. perhaps there is corrosion somewhere caused by the rain getting inside the cab?? Any good places to check 1st? Anyway, sorry for the wordy description but i thought I would give all the facts that might be pertinent to the problem. Any and all advice and suggestions are greatly appreciated!

 

Put a couple bottles of Techron or Gumout with PEA in the gas to see if that helps the misfire. How old are the spark plugs? The ABS system may need some troubleshooting. Watch a few utube videos about how to go about that.

 

Only have about 40,000 miles on the plugs. As far as the ABS, I am thinking that since the truck sat for a while maybe a rodent got in there and did some chewing. Or perhaps some battery acid got onto the right side ABS lead (right under the battery).

 

The U3FFF is a communications issue between modules.
The P1000 is telling you the diagnostics have not all completed.
When they complete trouble free, the 1000 will clear.
You have 4 wheel ABS if there are front wheel sensors..
It is a different system that just rear ABS.

 

3rd brake light....common leak...abs stuff without my notes not sure what all you got there. I know the ABS modules are NOT what you would call GREAT. (PITA) I just did mine earlier this yr. Gave me like 3 or 4 codes....rear sensor was 1 of them... (also easiest to check ) so jack up truck plug in tester to sensor...run up to like 10 mph...sensor is GOOD but ecm/ABS module didn't think so.... short story was module was getting a "power relay" code C115 ....light would be out upon start up....then come on within 5 minutes of driving..like WTF. anyway module was jacked up..
sent it to
https://www.myairbags.com/

was maybe $100 turned around in 3 days and YES you can drive the truck with NO MODULE....its like driving an ancient car...you know..BEFORE ABS BRAKES!!!lol

 

Note this;
The wheel and rear speed sensor are not tested until the vehicle reaches over about 5 mph.
Reason is there would be no signal until the sensor could detect it and the module responds.
As a result, the power up test of the module would test ok, put the ABS light out if the module is good then it can detect wheel sensors output when the vehicle moves above a certain speed.
If a sensor is not outputting, the ABS light comes back on.
It's a logic decision in the system design.
Are there resistance reading to be looked at? yes but use the logic first, verify second as it may or may not show the fault as a first test..
Good luck.