Code P1233


Waldo

GT Owner
Mark IV Lifetime
Sep 7, 2005
756
Fort Worth, TX
Could a bad relay also throw a P0611 code? My GT was throwing an intermittent P0611 code during a dyno session yesterday.

Is there an easy way to check and confirm a bad relay?

Best Regards,
Waldo
 
Last edited:

tmcphail

GT Owner/Vendor
Mark IV Lifetime
Apr 24, 2006
4,002
St Augustine, Florida
Totally unrelated. As I stated yesterday I believe that was a fluke :

P0611 FUEL INJECTOR CONTROL MODULE PERFORMANCE

Possible causes
- Open or short fuel injector control module circuit
- Fuel injector control module power or ground circuit
- Failed Fuel Injection Control Module (FICM)
 

STORMCAT

GT
Mark IV Lifetime
Le Mans 2010 Supporter
May 25, 2006
7,408
Ft. Lauderdale
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.
Hello Clinton. The tech who looked at my car told me the primary pump runs all the time. The secondary pump only come on when the demand is required. Which made sense to me as far as the relay failing . The primary relay would pull in and stay contacted. If you are in the upper power band and in and out of the throttle the secondar relay would pull in and out and that would cause more where and tear on the relay. Torrie would probaly know... Torrie are you listening ??
 

STORMCAT

GT
Mark IV Lifetime
Le Mans 2010 Supporter
May 25, 2006
7,408
Ft. Lauderdale
Brian,
The first step I did was to replace the relays, which did not fix the problem I was having. In my situation, it appears that the fuel pump was the culprit.
Thanks for sharing your issue and cure.. It sounds like I got off easy !!
 

STORMCAT

GT
Mark IV Lifetime
Le Mans 2010 Supporter
May 25, 2006
7,408
Ft. Lauderdale
Ha right. I was on site for all of it so that helps as well. 6 years ago wow. Actually this is about the weekend I lost my mind in that car. The initial dyno work was done on 4-22-06, Joe was kind enough to throw me into the passenger seat for a ride that night and I completely lost my mind and picked up my car on 4-28-06.
And now you know the rest of the story !! or and please clarify post 25 please .. :biggrin
 

BlackICE

GT Owner
Nov 2, 2005
1,412
SF Bay Area in California
Hello Clinton. The tech who looked at my car told me the primary pump runs all the time. The secondary pump only come on when the demand is required. Which made sense to me as far as the relay failing . The primary relay would pull in and stay contacted. If you are in the upper power band and in and out of the throttle the secondar relay would pull in and out and that would cause more where and tear on the relay. Torrie would probaly know... Torrie are you listening ??
That is why I don't go to a Ford dealer to work on my car. Look at the wiring diagram both relays are always powered as long as the key is on and the inertial switch is not tripped. I studied this before installing the BAP. I never heard my BAP relays turning on or off other than when the ignition is turned on and they are triggered by the regular fuel pump relays. Constantly turning relays on and off is a good way to wear them out.
 
Last edited:

Wwabbit

GT Owner
Mar 21, 2012
1,259
Knoxville, TN
So what happens to the instantaneous mixture when a pump goes intermittent due to poor points? At high power settings (manifold pressures) sudden lean conditions are serious issues in the combustion chamber. Has anybody seen what their exhaust is doing when this happens?
 

Wwabbit

GT Owner
Mar 21, 2012
1,259
Knoxville, TN
...is the ECU and throttle body fast acting enough to manage a sudden drop in fuel flow at high power?
 

jcthorne

GT Owner
Aug 30, 2011
792
Houston
That is why I don't go to a Ford dealer to work on my car. Look at the wiring diagram both relays are always powered as long as the key is on and the inertial switch is not tripped. I studied this before installing the BAP. I never heard my BAP relays turning on or off other than when the ignition is turned on and they are triggered by the regular fuel pump relays. Constantly turning relays on and off is a good way to wear them out.
You are both right, sort of. The PCM only runs the primary pump normally and low throttle. Look again at the wiring diagram. The PCM controls the GROUND side of the circuit (most transister based controls do). The fuel pump is pulse width modulated output to control fuel pressure in the fuel rail. There is a pressure transducer there to provide feedback. Near 4000 RPM at WOT, the PCM runs out of effective pump capacity on one pump and begins using both. There is no pressure or flow spike, the pressure is still controlled at the fuel rail. Neither pump is at 100% output.

The relays only supply the +12v power and cut off on loss of ignition switch or inertia switch. The speed of the pump is controlled by the PCM. Hope this helps.
 

Colton74

GT Owner
Mark II Lifetime
Aug 4, 2010
152
Edmonton, Alberta
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

GT Owner
Nov 2, 2005
1,412
SF Bay Area in California
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/showthread.php?6539-Got-a-P1238-code-car-will-not-go-into-boost-help-!&highlight=relay
 
Last edited:

tmcphail

GT Owner/Vendor
Mark IV Lifetime
Apr 24, 2006
4,002
St Augustine, Florida
I second this check and or replace the relays and fuses for the FPDM.
 

Superfly

HERITAGE GT OWNER
Mark II Lifetime
Jun 23, 2008
2,210
Edmonton, Alberta
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

GT Owner
Mark II Lifetime
Aug 4, 2010
152
Edmonton, Alberta
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

GT Owner
Nov 2, 2006
810
Did you try to clear the code?
 

Colton74

GT Owner
Mark II Lifetime
Aug 4, 2010
152
Edmonton, Alberta
Did you try to clear the code?
I didnt try that yet, I will try that a little later tonight.

Steve
 

Wwabbit

GT Owner
Mar 21, 2012
1,259
Knoxville, TN
You are both right, sort of. The PCM only runs the primary pump normally and low throttle. Look again at the wiring diagram. The PCM controls the GROUND side of the circuit (most transister based controls do). The fuel pump is pulse width modulated output to control fuel pressure in the fuel rail. There is a pressure transducer there to provide feedback. Near 4000 RPM at WOT, the PCM runs out of effective pump capacity on one pump and begins using both. There is no pressure or flow spike, the pressure is still controlled at the fuel rail. Neither pump is at 100% output.

The relays only supply the +12v power and cut off on loss of ignition switch or inertia switch. The speed of the pump is controlled by the PCM. Hope this helps.
Now there's a good class in GT fuel systems. Thanks for that. I'm just starting to study it, but the use of a fuel 'buss' is interesting and makes sense. But what about any sudden loss of pump output due to pump drop out for any reason at high manifold pressures? What protects the engine from sudden lean conditions. This occurrence and condition seems pervasive. Please tell us.
 

STORMCAT

GT
Mark IV Lifetime
Le Mans 2010 Supporter
May 25, 2006
7,408
Ft. Lauderdale
That is why I don't go to a Ford dealer to work on my car. Look at the wiring diagram both relays are always powered as long as the key is on and the inertial switch is not tripped. I studied this before installing the BAP. I never heard my BAP relays turning on or off other than when the ignition is turned on and they are triggered by the regular fuel pump relays. Constantly turning relays on and off is a good way to wear them out.

I never studied the diagrams.. There are relays in for the turn signals and wipers. The points are like the old distributor points they are a weak link but are designed to cycle in and out. From what jcthorne describes I am not going to bash my dealer tech.. :biggrin

You are both right, sort of. The PCM only runs the primary pump normally and low throttle. Look again at the wiring diagram. The PCM controls the GROUND side of the circuit (most transister based controls do). The fuel pump is pulse width modulated output to control fuel pressure in the fuel rail. There is a pressure transducer there to provide feedback. Near 4000 RPM at WOT, the PCM runs out of effective pump capacity on one pump and begins using both. There is no pressure or flow spike, the pressure is still controlled at the fuel rail. Neither pump is at 100% output.

The relays only supply the +12v power and cut off on loss of ignition switch or inertia switch. The speed of the pump is controlled by the PCM. Hope this helps.
Thank you for the further detail. That's sound closer to what the GT tech described to me. I guess the fuel pump driver modules are an additional controller and control the pumps like a VFD
 
Last edited:

BlackICE

GT Owner
Nov 2, 2005
1,412
SF Bay Area in California
I don't know for sure how the pump are driven could be one at a time. I just relayed what Tony G told me and I haven't tested it myself. That would require monitoring either the signal into or preferably output of the FPDM. The ECU has the control wire to run each pump independently. However I wouldn't be suprise if he is right, it saves the designer from using another output line from ECU that isn't needed. The relays are always on and only cycle with the key.

The fuel pump motors driven using pulse width modulation, or PWM. Usually the control signal is a fixed frequency square wave of varying duty cycle used to drive a MOSFET or IGBT which gates a high current load to the pump motors.
 

GT350H

GT Owner
Mark II Lifetime
Mar 3, 2006
67
Portland, Oregon
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.