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Old 08-02-2010, 11:47 AM   #1
BTEliminatorII
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Help/Code P0068 Map/Maf Throttle Position Correlation

Well, I thought I was doing the right thing when I let my buddy drive the Goat home from a Pig Roast Sat. night, Wrong! He decided to get on it in 3rd and when he ATTEMTED to shift to 4th he grabbed 2nd gear instead Although he pushed the cluch back in pretty quickly, the car started running on what seemed to be 4 cylinders. I noticed a "Safe Mode" flash on the dash.

With the engine light on I limped it home. Gauges all read normal. I hooked up a Diablo Tuner on Sunday and it read "P0068" Map/Maf Throttle Position Correlation. Any help would be appreciated!!!
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Old 08-02-2010, 11:51 AM   #2
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unplug the battery, let it sit for a few minutes (10-15)
plug it back in. if it still runs like shit, your buddy owes you a motor.
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Old 08-02-2010, 03:27 PM   #3
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You might as well do a TPS relearn since you will be disconnecting the battery. Sounds ugly!
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Old 08-02-2010, 03:46 PM   #4
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I see bent pushrods in your future.
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Old 08-02-2010, 03:54 PM   #5
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Dtc p0068

The ECM compares throttle position to expected engine load based on MAF and MAP sensor inputs. If the ECM determines that the current load and throttle position are not consistent with the expected load and throttle position, DTC P0068 is set.

TPS sensor failure was common with 05 GTO's. When the sensor fails the ECM puts the engine in safe (reduced power) mode.
If it was a Toyota your friend might be dead.
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Old 08-02-2010, 04:28 PM   #6
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^^^ Yep...and that means you got broken hardware.
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Old 08-03-2010, 03:04 AM   #7
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Quote:
Originally Posted by GTOZZ...View Post
The ECM compares throttle position to expected engine load based on MAF and MAP sensor inputs. If the ECM determines that the current load and throttle position are not consistent with the expected load and throttle position, DTC P0068 is set.

TPS sensor failure was common with 05 GTO's. When the sensor fails the ECM puts the engine in safe (reduced power) mode.
If it was a Toyota your friend might be dead.

I'll Rp. the TPS sensor today and hope for the best. Oil pressure is normal and there is no banging, clicking going on. It went from what seemed to be running on four cyl. to a whopping six or so now.

On the bright side I have been talking with his brother who is an accomplished engine builder about doing a stroker for me one day.., just not Today!!!
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Old 08-03-2010, 03:10 AM   #8
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Quote:
Originally Posted by lanceygto...View Post
You might as well do a TPS relearn since you will be disconnecting the battery. Sounds ugly!

Uh.., How do you do that TPS is incorporated with the Throttle Body, only $561.00 + tax for a new one. Is there a test to make sure it's defective? I disconnected the TPS and turned the key on for 30 sec. then reconnected it to no avail. Also I have disconnected to battery for an hour.

Last edited by BTEliminatorII; 08-03-2010 at 05:14 AM.
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Old 08-03-2010, 05:21 AM   #9
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You've got the diablo right? Clear the code and see if it comes back up.
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Old 08-03-2010, 05:53 AM   #10
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Yes, I cleared the code but the engine light is still on. I just checked the trouble codes again and now it says 1) P0122 Throttle/Pedal Sensor A circuit low imput and 2) P0223 Throttle/Pedal Position sensor B circuit high input.

Last edited by BTEliminatorII; 08-03-2010 at 06:05 AM.
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Old 08-03-2010, 05:53 AM   #11
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Quote:
Originally Posted by BTEliminatorII...View Post
Yes, I cleared the code but the engine light is still on.

Is it still running like on 4 cylinders?
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Old 08-03-2010, 06:20 AM   #12
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Ya, still running like it's on six cylinders.
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Old 08-03-2010, 06:21 AM   #13
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Quote:
Originally Posted by BTEliminatorII...View Post
Yes, I cleared the code but the engine light is still on. I just checked the trouble codes again and now it says 1) P0122 Throttle/Pedal Sensor A circuit low imput and 2) P0223 Throttle/Pedal Position sensor B circuit high input.

Still runs like its on six sylinders
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Old 08-03-2010, 06:22 AM   #14
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Id start looking at mechanicals.
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Old 08-03-2010, 07:02 AM   #15
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Gremlins ate your car. When you clear those codes, do they keep coming back?

And are you clearing the codes with the car on, or off?
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Old 08-03-2010, 07:10 AM   #16
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Quote:
Originally Posted by andrewzpsu...View Post
Gremlins ate your car. When you clear those codes, do they keep coming back?

And are you clearing the codes with the car on, or off?

Ha Ha, for sure. All of the codes were seen or cleared with the key on, engine not running. Have not cleared the P0122 and P0223 yet.
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Old 08-03-2010, 01:20 PM   #17
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Do a compression test....you will probably find a couple cylinders with unusual numbers...those will be the ones with bent pushrods/valves, etc.
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Old 08-03-2010, 01:32 PM   #18
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Just pulled the plugs and they are quite black. I'll do a comp. test right now before pulling the valve cover, Thanks!
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Old 08-03-2010, 01:35 PM   #19
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It's ok to crank the engine without any wires connected, right?
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Old 08-03-2010, 01:51 PM   #20
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Yeah...should be fine. Wouldn't hurt to unplug the fuel injectors....or pull the fuse for the fuel injection on the pass side inner fender fuse panel.
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Old 08-03-2010, 01:51 PM   #21
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or pull the fuel pump relay, whichever.
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Old 08-03-2010, 02:18 PM   #22
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Quote:
Originally Posted by mechanic58...View Post
Yeah...should be fine. Wouldn't hurt to unplug the fuel injectors....or pull the fuse for the fuel injection on the pass side inner fender fuse panel.

Ok, I'll pull the fuse, waiting for the comp. tester, Thanks
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Old 08-03-2010, 02:23 PM   #23
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Quote:
Originally Posted by 06GTslOw...View Post
You're talking about the same wire in these two posts correct? Spark plug wires I assume?

Yes, I need to learn to be very specific when asking for advice

Last edited by BTEliminatorII; 08-03-2010 at 02:25 PM.
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Old 08-03-2010, 06:03 PM   #24
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Quote:
Originally Posted by mechanic58...View Post
Do a compression test....you will probably find a couple cylinders with unusual numbers...those will be the ones with bent pushrods/valves, etc.

Ya, did the old finger compression test and #5 didn't show up to play, neither did #6, so I called it a day. Pullin' the valve covers tommorow to see what's wrong. The engine turned over very smoothly with no plugs in so we'll see. Thanks for everyone's replies! I'll let you know what I find..,
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Old 08-03-2010, 06:52 PM   #25
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Hopefully he just folded up a couple pushrods...but you could have some bent valves. When you get the valve covers off, remove the rockers on those cylinders and re-do the compression test...if you still get nothing then you got some bent valves.
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Old 08-04-2010, 02:54 AM   #26
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Took a vacation day to check the carnage. If I do a cylinder leak down test on each cyl. with the rockers removed that should that assure me the valves are straight, correct?

Last edited by BTEliminatorII; 08-04-2010 at 05:12 AM.
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Old 08-04-2010, 10:04 AM   #27
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The Bad and the Ugly aftermath= Cyl. #5 / #6 and #8 at 100% comp. loss. Time to pull the heads. I'm assuming the only way you bend valves is by them touching the pistons.., looks like I'll be saving for a stroker..,
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Old 08-04-2010, 01:33 PM   #28
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It could be that the valves are the only casualty. If it looks like there was a pretty hard strike, it might not hurt to do a rod bearing inspection...it could have also possibly cracked a piston skirt (worse case scenario)...but chances are that the shortblock was not damaged.
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Old 08-04-2010, 08:08 PM   #29
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Yep, Piston #5 looks like it went a few rounds with Joe Fraizer and #6 & 8 didn't fair much better. I'm not going to take a chance on the short block, time for a 404ci. My "friends" brother is going to hook me up, ya right..,
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Old 08-05-2010, 05:54 AM   #30
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Well that sucks. Thats why they call this the money shift.
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