Help with codes please!!!

[Go Mifuni]

The pre-story:
A while back (much to the complete joy of a few here :P) I finally had my gears installed. Because it was an older mod package, it came with a chip (Diablo) programmed with all the goodies and the speedo correction.
Well, when I picked my car up from the shop (which was highly recommended, btw) my "Check Engine" light was on. I was told it might be due to the chip.
I got the car home and tried it with and without the chip. The results were the same. After reconnecting the battery and starting the engine, the light would be off. However, the next time I started the car the light would come back on.
One day, I was showing my car (which is still for sale, btw) and Courtmarshal reset the light with his Scangauge. This time, the light stayed off for TWO engine restarts.
Anyway, I need to get her inspected this month and I probably can't do it with the Check Engine light on so...
Can someone please tell me what these codes mean and what I need to replace?
The codes are:
P0406 (EGR flow Sensor A [not legible] high input)
P1451 (manufacturer control auxiliary emission controls)

Thanx a bunch :D

[RF Overlord]

Mike, I've recently obtained some much more detailed OBD-II diagnostic info from Ford than I had when you first developed the problem. Hopefully this will help.

P0406 is DPFE Circuit High
P1451 is Canister Vent Solenoid output circuit open.

DPFE is the Delta Pressure Feedback EGR transducer. On the 4V motor, this is part of the EGR valve module, not a separate part as in earlier years. The code you get means it is giving the PCM a voltage reading that is out-of-range on the high end (greater than 4.96VDC). Find the EGR valve module...it's bolted to the upper intake manifold on the passenger side, just to the left (or rear) of where the PCV valve hose attaches. Unplug the electrical connector and shoot some WD-40 in both halves and reconnect. If this doesn't fix it, the module itself may be bad.

For the CVS code (P1451), that refers to the Evaporative Emissions Canister, which is the flat black unit bolted to the underside of the truck floor. It's held on with 4 bolts. Pull that down and do the same for the electrical connector that you did with the EGR valve. If that doesn't fix it, then the Canister Vent Solenoid may be defective.

*EDIT* Mike, there are also a couple of wiring harness connectors that are right near the main connector for the PCM that could have been disturbed when the PCM was removed for installation of the chip. I have the factory wiring diagram and would be glad to help if you want to pursue it further.

[Go Mifuni]

Thanks Bob. As soon as things dry out, I'll climb under there.

[Paul T. Casey]

I believe you stated that the CEL was on when you picked up the car. If this is the case, it may be poor tuning in the chip itself. Do the stuff Bob says, and if the condition persists, it may be necessary to head to the tuner. I'm sure there are some good ones near-by, their names escape me at the moment.

[RF Overlord]

Paul, Mike said it does it even with the chip removed.

I was there when he had the work done (some of it anyway) and I'm thinking it's going to be "connector-itis". There's one right by the PCM connector that has the wiring for the CVS, and the harness for the EGR module runs right by there as well...

[Go Mifuni]

Paul, Mike said it does it even with the chip removed.

I was there when he had the work done (some of it anyway) and I'm thinking it's going to be "connector-itis". There's one right by the PCM connector that has the wiring for the CVS, and the harness for the EGR module runs right by there as well...

Bob, how tough is it to get in to check the connections by the PCM? I'm sure I'll need to pop the plastic cover off but is there anything else that would be in the way? All I'll need is a flashlight, right?

Oh, if I DO find some loose connections and fix them, will the light go out on it's own or will I need to reset it?

[BlownMerc]

There are no connectors in common between the two components except for the PCM connector itself. The evap canister vent solenoid is a two wire actuator, it gets Vpower from fuse F1.20 in the battery junction box on the red/yellow wire. If the PCM doesn't see 12V on the violet/white wire with the key on, it will set P1451. Check for power at the can vent connector and verify the shop didn't damage or disconnect anything while doing the gear since it is directly behind the differential. The EGR valve is probably the culprit on the other code, have seen quite a few since going to that design. Nowhere near as bad as the old DPFE sensor, but still have seen a few. Checking the connections as RF Overlord described is not a bad idea as it costs nothing and could save you some money. Good luck.

[RF Overlord]

BlownMerc, there is a connector (C268 I think...I'm not near my wiring manual) for the CVS that is right near the master cylinder. I was thinking that it could have been disturbed when the PCM was removed.

Mike, I'm not sure what plastic cover you're referring to, but I can e-mail you a copy of the picture in the wiring manual that details the connector I'm talking about above. This is in addition to the EGR connector, and the connector at the CVS itself, which is inside the evap canister unit under the trunk.

[Go Mifuni]

BlownMerc, there is a connector (C268 I think...I'm not near my wiring manual) for the CVS that is right near the master cylinder. I was thinking that it could have been disturbed when the PCM was removed.

Mike, I'm not sure what plastic cover you're referring to, but I can e-mail you a copy of the picture in the wiring manual that details the connector I'm talking about above. This is in addition to the EGR connector, and the connector at the CVS itself, which is inside the evap canister unit under the trunk.

Pictures are worth a thousand words. Thanks Bob. :D