Service Engine Soon and TPS code
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New User
Joined: Apr 2004
Posts: 12
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From: Forest, MS
Service Engine Soon and TPS code
Gentlemen/Ladies,
I have a '99 f150 with 102,000 trouble free miles..until now. I am getting a code for the Throttle position sensor. The Service Engine Soon light came on and for the last year every so often it will "rev up" like it had a stuck choke (of course I understand it doesn't have a choke...but acts like it does).
Anyway, i've been putting it off and it's becoming more frequent. Also, the battery light flickers on and off...especially at low throttle. Is this tied to the TPS problem or do I have other issues like alternator/battery?
I'm really needing to do a service on this truck, but I'm hesitating due to 100,000 trouble free miles.......only oil and coolant changes...that's it! Still has the original battery in it!
Oh yeah..if it matters..this is a five speed.
I have a '99 f150 with 102,000 trouble free miles..until now. I am getting a code for the Throttle position sensor. The Service Engine Soon light came on and for the last year every so often it will "rev up" like it had a stuck choke (of course I understand it doesn't have a choke...but acts like it does).
Anyway, i've been putting it off and it's becoming more frequent. Also, the battery light flickers on and off...especially at low throttle. Is this tied to the TPS problem or do I have other issues like alternator/battery?
I'm really needing to do a service on this truck, but I'm hesitating due to 100,000 trouble free miles.......only oil and coolant changes...that's it! Still has the original battery in it!
Oh yeah..if it matters..this is a five speed.
Hotshot
Joined: Jan 2004
Posts: 19,768
Likes: 1,082
From: St Louis
Need:
1) EXACT fault code (not some lame description)
2) Specific engine
If the flickering battery light corresponds to a drop in idle speed, ie, below 700 RPMs or so, the idle needs to be corrected. If the light is coming on at higher speeds, either the alternator or the battery is getting weak. At 8 years and over 100K miles, your battery is on borrowed time anyway and it is far more likely to suddenly leave you stranded at a very inconvenient time and place. I'd strongly consider replacing it.
Steve
1) EXACT fault code (not some lame description)
2) Specific engine
If the flickering battery light corresponds to a drop in idle speed, ie, below 700 RPMs or so, the idle needs to be corrected. If the light is coming on at higher speeds, either the alternator or the battery is getting weak. At 8 years and over 100K miles, your battery is on borrowed time anyway and it is far more likely to suddenly leave you stranded at a very inconvenient time and place. I'd strongly consider replacing it.
Steve
Hotshot
Joined: Jan 2004
Posts: 19,768
Likes: 1,082
From: St Louis
Originally Posted by bigredneck47240
yeah i would change the battery and try resetting the computer by pulling off the positive battery cable for about a min while the engine is off
BTW, the positive cable should be left alone. ALWAYS disconnect the NEGATIVE cable first...
If you don't know why this is important, it's due to the possibility of your wrench accidently making contact to ground while putzing with the positive terminal. Have you ever arc-welded anything??
Steve
Hotshot
Joined: Jan 2004
Posts: 19,768
Likes: 1,082
From: St Louis
Originally Posted by bigredneck47240
yes i have arch welded and out of 11 yrs of workin on vehicles i have always just undone the positive cable to reset the battery and never have had a problem
The factory service manual is quite explicit in the order in which cables are to be disconnected and reconnected. For a good reason.
Steve
Senior User
Joined: Nov 2006
Posts: 252
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guys, chill.
who cares which cable you take off first, just dont touch the wrench to anything. they do make a battery wrench that is insulated... wow! Anyway...
I would probably just shotgun a throttle position sensor, they get open spots in them and they dont read, then when you hit the gas a little more it reads all the sudden and the PCM is like whoa we're revvin up so here we go. if you had a scan tool theres a few minor tests you could do to condemn the TPS, but i doubt you have a wiring problem, its probably just an issue with the potentiometer(TPS) where an open exists somewhere.
who cares which cable you take off first, just dont touch the wrench to anything. they do make a battery wrench that is insulated... wow! Anyway...
I would probably just shotgun a throttle position sensor, they get open spots in them and they dont read, then when you hit the gas a little more it reads all the sudden and the PCM is like whoa we're revvin up so here we go. if you had a scan tool theres a few minor tests you could do to condemn the TPS, but i doubt you have a wiring problem, its probably just an issue with the potentiometer(TPS) where an open exists somewhere.
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Posting Guru
Joined: Oct 2005
Posts: 2,209
Likes: 1
From: Louisville, Kentucky
I have to agree with Project. Negative cable is disconnected first for any electrical work to minimize the risk of electric shock and potential explosion of battery gasses. 
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