Engine light on / Revs limited to 1000

So the engine light on my 2004 LC100 4.7 v8 came on today, accompanied by loss of power in that no matter what I did with the gas pedal, revs wouldn't go above 1000. Am I right in thinking the car has put itself in "limp mode"?
The same thing happened when my wife was driving it a few weeks ago.

After stopping the car and turning it off and on again, the problem was resolved.. so far. Engine light is off and revs normal.
I do feel in the last week or so my gas consumption has been noticeably higher than normal by about 10-20%, though of course it's hard to compare exactly given varying driving conditions.

I should add that just over a month ago I had a case of contaminated fuel (gas had some kerosene mixed in it) that necessitated draining the fuel system and replacing the fuel filter, though I've no idea if that is related. I had similar loss of power then but without the engine light on, and after draining and replacing the filter the car was fine. Also the difference back then was when I completely floored the pedal, the revs did go up, whereas this time they didn't. I am certain though that I have had clean fuel during the last month so I don't think it's a case of that happening again.

Also I should add that the weather here has been extremely wet/stormy the last week, if that might be relevant, though it wasn't for at least 36hrs before the problem occurred.

So my question is...

- Any ideas as to likely cause?

- I'm taking it to my (independent) garage tomorrow. Does anyone know if the 2004 LC100 uses OBD or OBD-II diagnostics? It's a Japanese Domestic Market version. Assuming there is some record of the engine light going on in the diagnostics, can anyone direct me to a list of OBD/OBD-II codes for this particular model?

Apologies if a similar question has been asked before, feel free to direct me to a relvant previous thread...

Thanks

OBD2 and betting it's a coil pack.

Mechanic was busy today, will have to wait to take the car in. One other question, if the engine light goes on and an error code is registered in the ECU - does it stay in memory when the car is switched off and on?

Yes, they are stored.

Check out coolant sensor.

don't start replacing anything until you get the codes read.

So my mechanic plugged in his OBD-II reader and.... nothing... the reader wouldn't connect. It works fine on his 2001 LC100 V8, all the other cars he's tried it on, but not mine. Is it possible that the connector is OBD but that Toyota has not implemented the OBD-II protocol on this particular car? I seem to remember reading somewhere here that some OBD ports on older Toyota's only used Toytota's own protocol. That said it seems odd it would work on his 2001 and not my 2004. Could it be because it's a JDM (Japanese Domestic Market) model? Attached is pic of the connector. Thanks....

The OBD questions was getting a bit off-topic for this thread so have moved them to a new thread.

Not sure what you have in the way of auto parts stores in Kenya but you may want to see if a local store or possibly even a dealership could read the codes for you.

Yeah we have a Toyota service center here. I was hoping to avoid taking it there though, I wasn't impressed when a few months ago they quoted me US$ 700 for a duplicate key (!). On this occasion I may have to, they charge $100 for a diagnostic though.

So I have an update on this. The problem happened again and lasted for an hour or so. Turning the car on/off didn't correct during that time. The next day it was OK though and has been for the last couple weeks.

But I gave in and took it to my local Toyota service centre, where they listed the problems as follows:

ENGINE:
1. Throttle body assembly needs cleaning
2. Air flow meter requires cleaning

ELECTRICAL:
3. Error code P2121 "Throttle/pedal position sensor (TPS)/switch "D"
circuit range/performance"
4. Throttle position sensor assembly "tampered with"
5. Throttle position sensor connector modified, wires not soldered.

OTHER:
6. Left and Right body ECU requires service/cleaning due to "invaded with small insects which might cause damage to the ECU) / overhaul dashboard
7. Front disc brakes noisy

Insects aside (!!! I think they mean ants, which is possible), it seems the problem is related to the pedal position sensor. So I took it to my own mechanic to have a look and he also noticed that the pedal sensor didn't look right. We read the part number (89281-47010, 198300-3011, 07F12A) and it appears that some previous owner had replaced the unit with an incorrect one, I think this one is from a Toyota Corolla or something, probably due to lack of parts here in Kenya. Welcome to Africa....

I have read the whole TPS/APPS thread but I am still not clear on the difference between the TPS sensor and the APPS sensor, as most of that thread relates to '98/'99 models. Mine is a 2004 Japanese specification, GH-UZJ100W-GNAGK, Engine 2UZ-FE. in this model are the TPS & APPS sensors BOTH by the pedal? Or is one in the engine by the throttle? Which is the one by the pedal? And which is the one that error code P2121 relates to?

Toyota quoted me about $550 for "#78010 - Pedal Assy, Accelerator".

That said, they also quoted me $1100 for a new throttle assembly when their own mechanic said all it needed was cleaning - when I questioned it they admitted the error - so I'm not sure how much I trust them.

If anyone can help me identify what the exact problem is, and what are the correct replacement part numbers, I'd be most grateful. I'll be travelling to the UK soon, so could maybe pick up the correct part there.

Thanks!

PS - On the OBD-II issue, it seems my vehicle is not OBD-II. I bought a bluetooth OBD-II reader which worked fine on my friend's UK VW Golf, but didn't work on my car. My mechanic's reader didn't work on mine either. But Toyota's Intelligent Tester did, which makes me think mine must be OBD-1 or M-OBD or other such protocol.

occamsrazor said:

I have read the whole TPS/APPS thread but I am still not clear on the difference between the TPS sensor and the APPS sensor, as most of that thread relates to '98/'99 models. Mine is a 2004 Japanese specification, GH-UZJ100W-GNAGK, Engine 2UZ-FE. in this model are the TPS & APPS sensors BOTH by the pedal? Or is one in the engine by the throttle? Which is the one by the pedal?

Click to expand...

Hi, Gently bumping this thread as still haven't worked it out. Particularly interested in the above quoted question. My mechanic says that in my model the TPS and APPS sensors are integrated into the pedal assembly - and neither sensor is in the engine compartment. All the info on this board relates to '99 era models and says they are separate and the TPS in by the pedal and the APPS next to the throttle, right?.
Can anyone with a 2003+ model confirm if what he says is the case? Many thanks...

On the US trucks, the TPS does not measure the pedal or linkage at all, it measures the actual position of the throttle butterfly. The APPS is the "accelerator pedal position sensor" it is located on the throttle body and the throttle cable connects directly to it. It creates and mechanical connection that allows the pedal cable to move the butterfly just a bit allowing for limp mode. In normal operation the APPS signal is used by the computer to position the throttle butterfly using the throttle butterfly motor (and the plate motion is verified/measured by the TPS).

What part number is your throttle body or could we have a picture of the throttle body?

Observing your photos it looks like yours is completely drive by wire without a throttle cable. Is that correct?

Correction, on older US trucks the APPS is on the throttle body. On the newer ones that have no cable and are completely wired the APPS is on the pedal. I BELIEVE this change was made in 2003 along with the rest of the major changes however it could have been sooner.

I think you have found the issue here - it seems that later models adopted a fully drive by wire (no cable) solution. I need to check the throttle area of my actual vehicle, but this is from a 2004 Landcruiser 100 series service manual I found on the net (can't tell which region though):
The document goes into great detail about how to diagnose problems with the sensors, including wiring diagrams and "normal" voltages from the sensors. It also provides a nice explanation of the APPS and TPS fail-safe modes:
So I think this clears up the issues as far as my model is concerned and explains the confusion over sensor location.

Now my only problem is finding a replacement. It seems that someone fitted the APPS of a different model vehicle to my truck, and because the wiring connector was incompatible they cut it out and connected the wires directly, which is probably the cause of my limp mode problems. The problems haven't reoccurred (fingers crossed) but I'd like to get the proper sensor installed. I've found a secondhand pedal assembly, the problem is I can't find a replacement for the wiring connector part on the vehicle that it is supposed to plug into, which seems to have been removed.

I am starting to see why people in Africa advise to buy a 4x4 with the least possible electronics... parts are a nightmare.

But I love my v8

While I long for an A750, one nice thing about the 2000 is the mechanical throttle backup. While difficult to modulate, I have verified almost full power with both APPS and TPS unplugged.

I'd trade my cable for an A750, but I sure as heck couldn't deal with two of those horrible dashes.

1loudLX said:

Correction, on older US trucks the APPS is on the throttle body. On the newer ones that have no cable and are completely wired the APPS is on the pedal. I BELIEVE this change was made in 2003 along with the rest of the major changes however it could have been sooner.

Click to expand...

Ahh yes, thanks for the clarification, I tend to get focused on my junk and forget the rest.

Glad the OP was able to differentiate between the two systems, pretty hard to identify which system we are talking about in the various threads.

OP, have you checked out the connector and wiring real well?

Hall type sensors are generally not failure prone but I could see it getting kicked or contaminated in that position.

Best of luck