TPS Guffaw

[spectre6000]

I took the scenic route down into town this afternoon, and was engine braking down some of the steeper stuff in 2nd gear (didn't let it get above 3K RPM). Not far into my otherwise leisurely drive, the check engine light came on.

When I got into town, I headed into O'Reilly and had them pull the code. It checked out P0120 (as I recall) indicating something amiss with the throttle position sensor. The O'Reilly guy told me it needed to be replaced, and he had one right here along with some tools to get down to it.

Unfortunately, but not surprisingly, the tools were crap and there wasn't much to work with. I've had this truck for less than a week and it's some 40 years newer than my previous ride, so I had lulled myself into some sort of sense of security and haven't yet felt the need to load a full compliment of tools in the back...

I pulled the EFI fuse to scrub the code, then got to work. I wasn't able to remove the lower screw using the cheap tools available to me, and managed to strip it quite badly. I put everything back together and went to the hardware store (my original destination) to get a screwdriver with a low enough profile (speaking of, I'm pretty impressed with this Doc Allen's Versatool and in no way affiliated) and some replacement screws in a harder alloy.

Since the code had been scrubbed, it hasn't come back on (with the original TPS). I'm new to cars with computers in them, so that may be temporary, but given that, I replaced the screws (having completely removed the original TPS and then just putting it back in).

My questions are:

1) Is it just a matter of time until the code throws again?

2) Did I screw up any sort of adjustments by removing the original TPS/are there any adjustments that should be made regarding its install? I see on earlier 4 cylinders, some adjustment is necessary, but from the FSM it looks like the thing either works or it doesn't (again, new to computers in my cars)...

3) Are issues with TPS typically rectifiable with some electronics cleaner? It looks like it's just your run o' the mill rheostat, and since there's really not much that can truly go wrong save getting a little dirt built up between the arms and the plate, it seems some electronics cleaner would do wonders. Again, new to cars with computers, there may be things involved that I'm not aware of in this particular system.

 

[athlon450]

Make sure the connections are clean in the plug. Check all your ground wires.

 

[spectre6000]

So, to answer the question, it's a plug and play affair?

 

[athlon450]

yes, on the newer models. My older truck with 22RE has some adjustment to it.

 

[tylerbaird]

Yes, the code will come back. When my TPS went bad, the code would come on for like half a day and then not come back for about a week. Also you'll want to use a Toyota TPS from the dealer, not one from a parts store.

 

[spectre6000]

yes, on the newer models. My older truck with 22RE has some adjustment to it.

How do you define "newer models"?

Yes, the code will come back. When my TPS went bad, the code would come on for like half a day and then not come back for about a week. Also you'll want to use a Toyota TPS from the dealer, not one from a parts store.

Why's that? Is there that significant a difference in quality? It's certainly not difficult to imagine, but I'd like to know if there's something to know. I've not been able to really just go out and get parts at a parts store until now (my newest car until recently turns 50 in June), so I was sort of excited at the prospect...

 

[zacattack20]

I got that code a couple years ago. Truck shut off on me on the freeway and check engine light came on. Started the truck back up and finished driving to work, checked the code and was for the throttle position sensor. Removed it and sprayed some electrical contact cleaner on the sensor and where it plugged in. Cleared the code and hasn't come back since. I would try just cleaning it first before going and buying a new sensor.

 

[98Base4R]

If you install a Scan Gauge, you can display the TPS value. When it starts jumping, the CEL will come one and the engine will stumble.

I got a CEL that would return after clearing. Went through the same issues with stripped screws. I installed two O'Reilly's BWD TPS. Each lasted a matter of hours before making the engine stumble harshly on the highway. When I returned the O'Reilly's defective parts, the counter guy peered at each of them and said, "Looks like it was installed incorrectly." Ummm... it only goes in one way.

Money in hand from O'Reilly's, bought a Toyota TPS from these guys: Toyota Parts - Genuine OEM Toyota Auto Parts and Accessories

Two morals to this story: Get a Scan Gauge, so you know what is going on. Don't buy electronics for your Toyota from O'Reilly's.

 

[spectre6000]

The CEL light came on while I was going through some back country roads. You can't get above 2nd gear, all loose stuff, and lots of down hill. Being used to old air cooled cars where up hills make your engine temps go up, and engine braking down them cools you back down, I was engine braking down the steep stuff (my understanding is that the 4Runner discs tend to warp). I braked when it got up to 3K RPM or so, but it was during this engine braking practice that the CEL came on. My immediate reaction was that it ran a bit lean due to the lack of throttle and threw a code for that; ignore it. I wonder if the throttle being forced open by the engine braking could have tripped the sensor when the throttle plate was opened by the air flow rather than the accelerator pedal. Again, new to fuel injection and computers and such, so I could be completely off. Just curious if any of the techie types have any insight on the function here.

Another trip into town (40 miles round trip for a total of approximately 60 miles since the light went off) resulted in no CEL.