I have a 2005 Mustang V6 Convertible w/ 5 Speed Auto trans and the wrench light keeps coming ON. The car has spent the last (2) weeks at (3) dealerships trying to diagnose the problem correctly and fix it.
Parts replaced so far:
(2) throttle body units - thought the TB sensor was bad in each case
(1) Accelerator pedal sensor
(1) Accelerator pedal assembly
(1) Wire harness to monitoring computer for main ECU
Diagnostic listing is too big to list for what has been done.
Symptoms:
1. Light comes ON at various speeds but seems to happen after car is completely warmed up and driven to speeds in excess of 70MPH. When ignition is turned OFF - the light resets itself. I also noted a slight LAG or feeling that the engine was turned OFF momentarily - split second in fact - and then the light comes ON. After the light comes ON - the car runs beautiful up to ANY speed without ANY glitches. I'm not bashful with the car and regularly take it to 90+MPH when I can. Has anyone had a problem with this or have ANY suggestions??
This is a shot in the dark, but try doing the computer reset thing. Disconnect the battery for 15 minutes, the reconnect and see if the problem still exists.
This actually reminds me of the joke where Bill Gates tells Henry Ford "If cars were like computers we have 1000 HP and get 100 MPG." To which Ford replies, "Yes and you'd be driving down the road and for no apparent reason the car would just stop running. Then you'd have to roll the windows down and then back up to get it to start."
The dealers have reset the computer, one said they "reflashed" the Eprom, and the third dealer is waiting for a tech from Detroit to come in and see what they can do. I will probably buy the new car tomorrow. Looking at (3) GTs - (1) 2006 GT Vert - loaded, (2) GT Coupes - California Style - (1) White & (1) Burgundy. I'll let you know how it goes
Sounds like you've got a good line-up of replacements.
Try and stay in touch with the dealership on your problem if you can. It would be a good thing to have a solution on it for the archives here in case anyone else encounters the same problem.
Talked to the Service Tech today about the status of repairs. Ford told them to go ahead and replace the main ECU computer since nothing else seems to be fixing the problem.
I gave up trying to buy a new one!! Ford is REAL proud of selling their Mustangs but they sure don't want them back. I bought the 2005 Mustang V6 Vert in 06/2005 for about $26K. They started out giving me a trade value of $14K and only came up to $16K once I went balistic on the Sales guy on a 2007 GT/CS Coupe!! I told them to get my car fixed ASAP!!
I'll go ahead a do some of the mods that I have been shopping around for. (ie GT Grille w/ fog lights, ground effects - if I can find a set that will fit the V6 Model, and maybe add a few amenities to the interior). Always open for suggestions.
Ok - the saga continues with the "Wrench Light ON" but with a few things starting to come together. First of all, FYI, I am an aircraft technician and inspector by trade and taught aviation electronics at Lewis University - big deal right??
Anyway, my dealer replaced the main ECU and test drove the car several times the last two days - the Wrench light stayed OFF - hurray!! I picked up the car this afternoon and drove it about 80 miles and didn't have the light come ON at all - thought it was fixed!! But - the car didn't feel like it was running right. It hesitated all the time at all different speeds and it just didn't "feel" right.
Went for a drive with my wife cuz it was such a nice night and the Wrench light came ON at about 30 MPH in city driving. The car bucked and hesitated the entire time we were driving. It was a warm day here in Chicago - 85 degrees and about 75 when this was happening. I also had pulled over into a parking lot and put the car in 'neutral' and let it idle for a couple minutes. I revved the engine up a little and then I tried to see how high the RPMs would go for grins and giggles - it topped out at 4000 RPM exactly and I had a lot of pedal movement to go to the floor!! I tried it several times and each time the engine would stop at 4000 RPM - like it had a governor attached to it. Not right!!
I read the Thread that was talking about resetting the throttle pedal to the ECU with a little interest and also the one about the fuel pump TSB. I went ahead and did the pedal reset and OMG - the car performed totally different - it was absolutely night and day!! I went and drove the car again and the car shifted better and now would shift at the 5500 - 6000 RPM when you really got into the pedal like it should. There was NO hesitation and NO bucking whatsoever. We went for another long drive and after about 40 minutes - the light came ON again. I pulled into another lot and performed the pedal reset again and drove for another hour. I covered all the parameters - city driving - stop and go - over 100MPH and back to city driving. The light didn't come ON at all!!
I'm thinking that the problem is possibly a combination of the fuel pump vapor locking as stated in the TSB (city driving and stop and go)and a mismatch of voltage readings between the gas pedal movement and the voltage reading that is necessary to make the throttle body plate to move in conjunction with the gas pedal.
Does anyone know where I can get the wiring diagram and test point voltages for the throttle body system. I could also use a comparison graph of performance vs voltage for throttle plate vs gas pedal movement. My service tech said he didn't have that available - bull!! Some engineer had to be able to show that he could operate the throttle plate electrically by moving the gas pedal.
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2005 V6 Premium Vert, Satin Silver, GT Body kit upgrade, Dark Charcoal Leather, Shaker 500, 17" Dark Bullet Wheels w/ Conti Pro Contact P235/55ZR17 Tires, Street Scene Fog light wiring harness
69Stang - thanks, that makes me feel a little better
stlwagon - the codes that are listed are as follows:
P2104
P2123
P2126
P2127
P2132
Ford had the last dealer run TSB050301 on the car too.
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2005 V6 Premium Vert, Satin Silver, GT Body kit upgrade, Dark Charcoal Leather, Shaker 500, 17" Dark Bullet Wheels w/ Conti Pro Contact P235/55ZR17 Tires, Street Scene Fog light wiring harness
Sorry about that - those are the EEC tests that were run as a result of the codes. I will call my service tech and ask him for the list of codes that came up.
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2005 V6 Premium Vert, Satin Silver, GT Body kit upgrade, Dark Charcoal Leather, Shaker 500, 17" Dark Bullet Wheels w/ Conti Pro Contact P235/55ZR17 Tires, Street Scene Fog light wiring harness
Stopped over at AutoZone and had them plug into the car. The light has been coming on quite a bit this morning and when I turn the car off, the light resets and stays off for a little while. Anyway, when the light came ON again, I stopped by at AutoZone and plugged into the car - there were NO codes locked in or showing at all!!
This car is driving me nuts!!
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2005 V6 Premium Vert, Satin Silver, GT Body kit upgrade, Dark Charcoal Leather, Shaker 500, 17" Dark Bullet Wheels w/ Conti Pro Contact P235/55ZR17 Tires, Street Scene Fog light wiring harness
Wrench light is ON!! 
