Code 543

I have a 94 Taurus with a 3.8L that I recently bought from a friend. When I got it, they told me that a mechanic told them that the hose from the fuel vapor valve to the PCV valve and crancase needed to stay disconnected, or it will die. It did die when connected, until I cleaned the throttle plate (gummed up really bad). It now runs better, but has slight miss. If I put it in neutral while rolling down the highway, the car will die. I took it to AutoZone, and it has a 543 code, which is a fuel pump circuit open, battery to ECA. Does anyone know what this code actually is or what the ECA is?

Are you sure of the code? Was it a P0543? If so, that is a generic OBD-II code defined as 'Intake Air Heater "A" Circuit Open.'

-Rod

I noticed you mentioned that you have a 3.8L. 1998 Taurus's came with 3.0L engines (except for the SHO) Perhaps when you went to reference your code you got the wrong definition?

Are you sure of the code? Was it a P0543? If so, that is a generic OBD-II code defined as 'Intake Air Heater "A" Circuit Open.'

-Rod


My bad. I did not proof read what I typed. It is a 1994 3.8L Taurus GL, not a 98. The code taken at AutoZone (they do it free) was a 543, which listed inthe Ford codes, is "fuel pump circuit open, battery to ECA".

Any ideas?

Do you know if your car has dual oxygen sensors?

From the factory service manual:
------------------------------------------------
Engine Starts:
-- HO2S short to power (dual HO2S applications).
-- Damaged Powertrain Control Module (PCM).


Does the engine start?
Yes
For dual HO2S applications:
GO to «J25».
All others:
REPLACE PCM. RERUN «Quick Test».

I believe that it does have dual O2 sensors. However, I am wondering if the PCM could be bad, because the AC won't turn on either, even though it is charged properly, and I swapped out the high pressure kick-out switch ont he accumulator just to see if that might be it's issue. ALso, driving it home from work today, it has a hesitation, almost a miss when I first take off and also when I put it in reverse. I also noticed that it is trying to stall when I decelerate quickly.

Any words of wisdom?

Ford PCMs are quite robust. So far your symptoms would not cause me to initially suspect the PCM. There are a lot of items that can cause the A/C to fail to work. How are you determining that it's properly charged? Over or undercharged can keep it from working, as can a bad clutch coil, bad sensor, bad relay, etc. Also, there are a lot of sensors that can cause the hesitation, and that could quite easily be related to the source of the diagnostic code.

-Rod