Code P1233

Colton74 · Oct 18, 2011

Started the car this morning in preparation for an evening appointment with it. Let it warm up and then decided I would take it into work instead of the truck. Warmed it up to operating temperature and then jumped in to back out of the garage.

I noticed the check engine light was on. Pulled back into the garage, plugged in the SCT tuner and codes were as follows.

P1000 which is typical and to be expected??

P1233 which I am having a little harder time with.

The car idles fine, seems to respond to light throttle fine, started with no problem and there are really no strange noises. It also is always on the battery tender. The fuel in the tank is below 1/4 mark, however still what I would consider fresh. It also has not been driven in about 2 weeks.

I did notice the last time I drove it that it seemed to be a little down on power even commenting to my passenger.

Any thoughts on what is happening? If so is it of major immediate concern or can it wait until I take it south for the winter?

Thanks in advance for any help.

Steve

BlackICE · Oct 18, 2011

This is a fuel pump driver module offline FPDM. The car has two so it will work in limp home mode with just one. The probable causes are a bad fuse or FPDM relay. Both are located under the trunk liner near the battery. A few on this board have had problems with the relay. I haven't heard of any FPDM failing yet.

NBD a simple inexpensive fix.

Read this thread.

http://www.fordgtforum.com/forums/s...will-not-go-into-boost-help-!&highlight=relay

tmcphail · Oct 18, 2011

I second this check and or replace the relays and fuses for the FPDM.

Superfly · Oct 18, 2011

Steve, if you're tackling the project this weekend, let me know. I might pop by to lend a hand (and toss about some smartass wisecracks if I can't help). ;-)

Colton74 · Oct 18, 2011

Pro - sounds good I will shoot you an email if I am going to have a go at it.

Thanks all for your help, I will have a look at the fuses etc.

Steve

paul b · Oct 18, 2011

Did you try to clear the code?

Colton74 · Oct 18, 2011

paul b said:
Did you try to clear the code?

I didnt try that yet, I will try that a little later tonight.

Steve

Colton74 · Oct 19, 2011

Tried to clear the code however they came back on right away. Car would not provide boost initially, however after a bit of driving the boost returned and felt like it normally does (which is awesome). I will check the fuses and the relay, however would it be possible for the belt to be slipping?

It didnt seem to be struggling for fuel at any throttle position. Does one pump kick in when needed or do they work together at all times??

tmcphail · Oct 19, 2011

I wouldn't beat on the vehicle until you have this solved.

Colton74 · Oct 19, 2011

Sorry, reread my post. By any throttle position I didnt mean "any" throttle position. Enough to cause little boost, not enough to induce a ticket. Car is parked until cause is found and repaired.

GT350H · Oct 20, 2011

I'm in the middle of dealing with a similar problem. Right at the conclusion of a recent Track Day, I noticed an immediate, significant loss of power. This same situation occured only once before during a Track Day about three years ago. In both cases, one of the two 15 amp fuses for the fuel pumps blew and the check engine light comes on and I pull a P1234 code. The first time it happened, we replaced the fuse and never had another issue with it until this last Track Day and this included several rack Days in between these two incidents. This time, I replaced the fuse and by the time I had driven the 10 miles home on the freeway, it had blown again. I consulted with Rich Brooks, Shadowman and Stormcat for their thoughts. Based on these discussions, I replaced two fuel pump relays and took the car out for a drive. The first 25 miles were fine, but toward the end of the drive I ran up to 105mph in third and the fuse blew again, so in my case, the relays were not the cause of my issue. It appears that when I'm accelerating with full throttle in excess of 3500-4000 RPM's, that's when the fuse blows.
The next step is to swap out the fuel pump drivers and see if that causes the other fuse to blow, hopefully isolating a specific driver as being the problem. If anybody has any other ideas on how to proceed, I'm all ears!

BlackICE · Oct 20, 2011

GT350H said:
I'm in the middle of dealing with a similar problem. Right at the conclusion of a recent Track Day, I noticed an immediate, significant loss of power. This same situation occured only once before during a Track Day about three years ago. In both cases, one of the two 15 amp fuses for the fuel pumps blew and the check engine light comes on and I pull a P1234 code. The first time it happened, we replaced the fuse and never had another issue with it until this last Track Day and this included several rack Days in between these two incidents. This time, I replaced the fuse and by the time I had driven the 10 miles home on the freeway, it had blown again. I consulted with Rich Brooks, Shadowman and Stormcat for their thoughts. Based on these discussions, I replaced two fuel pump relays and took the car out for a drive. The first 25 miles were fine, but toward the end of the drive I ran up to 105mph in third and the fuse blew again, so in my case, the relays were not the cause of my issue. It appears that when I'm accelerating with full throttle in excess of 3500-4000 RPM's, that's when the fuse blows.
The next step is to swap out the fuel pump drivers and see if that causes the other fuse to blow, hopefully isolating a specific driver as being the problem. If anybody has any other ideas on how to proceed, I'm all ears!

I would download the returnless fuel adaption table using your SCT 1st. That will tell you if your car is using more voltage and current to drive the pumps than usual which could be something as simple as a plugged up fuel filter. I doubt that you have two bad FPDMs. I can post the default table you can compare to later if you want it.

If it is not the fuel filter, my next guess would be bad alternator, low voltage increase pump current, then worn out pumps or a kinked fuel line like fubar had.

SteveA · Oct 20, 2011

Are these fuses and relays located in the passenger foot well?

2112 · Oct 20, 2011

SteveA said:
Are these fuses and relays located in the passenger foot well?

From an earlier post;

Both are located under the trunk liner near the battery

GT350H · Oct 20, 2011

No, the fuses and relays for the fuel pumps are located in the small fuse block located under the trunk liner under the front hood latch. There is another, larger fuse block located by the battery, but that is not where the fuel pump fuses and relays are located.

SteveA · Oct 20, 2011

Thanks guys, did read the thread but missed the location. Got a C- in comprehension.

Colton74 · Oct 23, 2011

I replaced the fuse for the pump and that seems to have done the trick. Is there anything in particular that could have caused this?

Thanks to all for your quick help.

GT350H · Apr 16, 2012

As a followup to my 10/19/11 post, the next issue I encountered was a p1238 code. At this point, the fuse was no longer blowing, but I had significantly reduced power all the time and the check engine light came on immediately upon start up. Our guess was the secondary fuel pump was no longer functioning and so we replaced that pump last week. The good news is I am back to full power, the check engine light does not come on and I am not blowing any fuses. It is also good news that the need to replace a fuel pump is rare and be thankful for that, because replacing a fuel pump with the tank in the car is a major PIA!
As always, thanks to the many contributors to this site for the tremendous amount of help they provide.

STORMCAT · Apr 18, 2012

GT350H said:
As a followup to my 10/19/11 post, the next issue I encountered was a p1238 code. At this point, the fuse was no longer blowing, but I had significantly reduced power all the time and the check engine light came on immediately upon start up. Our guess was the secondary fuel pump was no longer functioning and so we replaced that pump last week. The good news is I am back to full power, the check engine light does not come on and I am not blowing any fuses. It is also good news that the need to replace a fuel pump is rare and be thankful for that, because replacing a fuel pump with the tank in the car is a major PIA!
As always, thanks to the many contributors to this site for the tremendous amount of help they provide.

I had the same fuel delivery problems twice. It seems the relay problem may rigger more that one code. And the codes may differ if you have a tuner? Not sure just guessing on that.

I would have swapped out the relays before going to the pump. There have been lots of relay problems and very few pump failures. I am not saying your pump wasn't bad but if you incur the problem again go straight for the realys. I am not sure how hard you drive the car but this will only happen on hard pulls above 4000 rpm when the seconadry pump is needed

Here are my posts and if you see the relay contactor point it's easy to see why they seem to go away early. I wish there was a HD relay that would fit in the slot ..

Fuel Pump relays :

Detailed diagnosis post :
http://www.fordgtforum.com/forums/s...ble-Code-P1235&p=255925&viewfull=1#post255925

Photo:
http://www.fordgtforum.com/forums/s...ble-Code-P1235&p=255923&viewfull=1#post255923

Main Thread :

http://www.fordgtforum.com/forums/s...ble-Code-P1235&p=255923&viewfull=1#post255923

BlackICE · Apr 18, 2012

Brian, my understanding is that both pumps are always running, moving fuel in parallel. When one of the relays fail, one pump has to do the work of two and when you need higher fuel flow (under load, high RPM) one pump cannot maintain the pressure so the car probably misfires and loses power.

From looking at the wiring diagram both FPDM are always under power, but there are two different logic lines that tell each FPDM the duty cycle to run on each motor. It wasn't clear to me were the pump ran at the same duty cycle or different ones. TonyG (the man who tuned Joe's TT monster) was the one that told me that both pumps run the same. He also said in Joe's car he had to shoehorn into the tank in 3 pumps instead of 2.

Code P1233

GT Owner

GT Owner

GT Owner/Vendor

HERITAGE GT OWNER

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GT Owner

GT Owner

GT Owner/Vendor

GT Owner

GT Owner

GT Owner

GT Owner/B.O.D

Blue/white 06'

GT Owner

GT Owner/B.O.D

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GT

GT Owner