1997 F150
V6 4.2L
126,000 miles

Got a check engine light a couple of days ago.
Codes:
P1537 - Intake manifold runner control bank 1 stuck open
P1538 - Intake manifold runner control bank 2 stuck open
P401 - EGR related

Just today, air from vents is stuck between Defrost and floor setting.

1. Any suggestions for the codes?
2. Any suggestions for the problem with the vent airflow?
3. Could my two problems be related?

Thanks!

 

It is unlikely that the codes are related to the HVAC.

For the two IMRC codes, consult the PCED or try the SEARCH tool

For the P0401 code, try the SEARCH tool. Very commonly discussed.

For the airflow problems, check the vacuum line that runs through the firewall. Look for cracking etc between the battery and the firewall. Common location for vacuum leaks. Otherwise, possible vacuum leak, HVAC HU fault, or a faulty vacuum motor.

Steve

 

I had the same problem with my '97 F-150 when I put any load on the engine. It was a vacuum line. The problem went away when the line was replaced.

As for the codes, I am sorry I can't help anymore on that...

Good luck.

 

Well the egr and hvac are vac controlled so put a vac gauge on and make sure that system is up to snuff.

Adrianspeeder

 

You need to replace the dpfe for the 401. First, make sure that the engine idle will die out with vacuum applied to the egr valve. If so, replace the sensor. As for the other, I agree you have a bad vacuum line somewhere. The imrc valves are on the very rear of the intake and accessing them requires removal of the upper intake. Good luck.

Robbie

 

Even the P401 could be caused by a bad vacuum line. Start checking. I'd start at the PCV located on the passenger side valve cover. Notorious for crakcing where it attaches.

 

Look for the bad vacuum lines first. Then consider you could have 2 problems. I have personally seen both of the problems you describe at about the same mileage you are at now.

I agree that many times the P401 is the DPFE. But at the 126,000 mile range you really can start to see problems with the EGR itself. Many times you can clean it. In my experience it's best to replace it.

The IMRC is the air handler side of the fuel injection system, not the actual injectors. I've heard alot of technical explanations about the actual components. I'm no engine techie. I can only say I'm not surprised. When mine failed I found out that the IMRC has a lifespan between 100-150K. When the engine was designed by FORD, they knew this part would fail somewhere near the mileage you are at. It's simply a matter of wear and tear on the engine.