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  #1  
Old 01-23-2013, 07:47 PM
EdWindows's Avatar
EdWindows EdWindows is offline
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Lightbulb Addendum to checking TCU error codes

The following should be added to the check TCU error code how-to:
The last step in the error-checking (pressing the pedal) may not register if you have a bad TPS that throws a CEL, and therefore you will not be able to retrieve TCU codes!

I noticed this because when I first bought my car, I had the 16 power flashes and tried and tried and tried checking TCU codes both ways with no avail. Everyone I asked here was convinced I was doing something wrong, or they didn't know why it didn't work.
After replacing my TPS, I was able to check my codes with both methods on the first try.

PS: A bad TPS also causes the power mode light to be intermittent when a Power Mode switch/button is activated.
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1992 Dark Teal LS-L w/ 165k+ miles (traded )
Mods: Power Slot front rotors, polyurethane sway bar bushings, window scratcher fix, SPD hood struts, Outlaw Engineering phenolic spacers, Bontrager Works 22mm rear sway bar, R-134a conversion, 93 Legacy SS 5 speed swap, Ceika coilovers, ARP head studs

2001 Black Toyota Sequoia (hauler/daily)
1992 Blue Toyota Cressida (drift car)
1992 Red Toyota MR2 (weekend/track day car)
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  #2  
Old 01-23-2013, 08:17 PM
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Re: Addendum to checking TCU error codes

That makes sense actually. The TPS would be expected to sweep from open to closed, which might not happen if it's worn or has dead spots.

The easiest way I have found to test the TPS is using the ecutuner select monitor program. Because it gives you real-time data of what the ECU is reading from the TPS, you can slowly press the pedal, and watch the % throttle change. If it doesn't change linearly, then you will be able to see it.
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  #3  
Old 01-23-2013, 08:54 PM
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5spd + coilovers = win :D
 
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Re: Addendum to checking TCU error codes

Quote:
Originally Posted by icingdeath88 View Post
That makes sense actually. The TPS would be expected to sweep from open to closed, which might not happen if it's worn or has dead spots.

The easiest way I have found to test the TPS is using the ecutuner select monitor program. Because it gives you real-time data of what the ECU is reading from the TPS, you can slowly press the pedal, and watch the % throttle change. If it doesn't change linearly, then you will be able to see it.
I've been meaning to make one of those OBDI to USB cables to check various stuff.
EDIT: Also, during the method to check for previous problems, my TCU showed code 31 which is for a bad TPS.
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1992 Dark Teal LS-L w/ 165k+ miles (traded )
Mods: Power Slot front rotors, polyurethane sway bar bushings, window scratcher fix, SPD hood struts, Outlaw Engineering phenolic spacers, Bontrager Works 22mm rear sway bar, R-134a conversion, 93 Legacy SS 5 speed swap, Ceika coilovers, ARP head studs

2001 Black Toyota Sequoia (hauler/daily)
1992 Blue Toyota Cressida (drift car)
1992 Red Toyota MR2 (weekend/track day car)

Last edited by EdWindows; 01-23-2013 at 09:25 PM.
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  #4  
Old 01-24-2013, 09:05 PM
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Re: Addendum to checking TCU error codes

You don't have to make a cable (the instructions out there for diy cables may work a lot of the time but they aren't really correct by the by. They don't use the right line driver that's why they have the "92 problem" they try to work around with a comparator). I sell the correct select monitor interface with select monitor harness. Check out my page on the ecutuner aplication and select monitor interface. Like icing was saying it's by far the easiest way to do diagnostics and to adjust your new tps.


Quote:
Originally Posted by EdWindows View Post
I've been meaning to make one of those OBDI to USB cables to check various stuff.
EDIT: Also, during the method to check for previous problems, my TCU showed code 31 which is for a bad TPS.
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