did you just replace (splice in) a new piece of wire or did you run a new ground wire?

Hello Guys, thanks to all for your help.

Finally the problem of the ignition was in the main valve, that comes of the cylinder, this valve had a bad electric contact, when this was should open, it was flashing, the problem was solved when i replaced this wire

These unit have a "known concern' relating to the wire harness for the throttle body, and a fuse that does not show in earlier schematics, for the throttle body. That fuse being blown or removed will set an e-23 code, as well as if the wire harness is pulled apart or the pins pulled out of the connector right near the throttle body. Often near where it bends into the rest of the harness.
There is also the concern of the changes to the throttle body and where/and the type of the pressure sensor mounted to the throttle body.
I would point out (swoop) that MCFA did not have a Nissan K21-k25 powered tier 1 truck, (tier 1 was 2003, and a 4g63-4g64 powered truck) but that the 2004 version was indeed a bit different from the 2005 and newer units as to where the diagnostic connection is found (among other changes).
It is also worth noting that not all MCFA trucks had an OBD2 connection in/under the cup holder, and I am pretty sure I have seen some that had a different style of connection that was not shaped with the OBD2 style angled sides.
I guess It should also be pointed out that swapping of the ECM from a slightly later serial number (or different model) is not recommended as they will plug up but then throw errors as they use differing schemes for the throttle body fuel pressure sensor, and ratios in the transmission sensor.
Yansteven, the legality of sharing copyrighted information is done by each country, so what is of concern to someone in the USA or Australia, may not be the same concern for someone in some other country.

ey? Language barrier... Ey? 'nations separated by a shared tongue' Ey?

Now I get to throw in my own $.02USD W.A.G.:
in the relay box that you find in the engine compartment, swap the relays around (or replace all the relays) and see if it changes. if you have an all LPG truck, the fuel pump relay is a 'spare', as LPG does not need a fuel pump.

Swoop these systems will not operate the butterfly in the TC without running if i am remembering correctly. But you can get a good idea behind what is happening through software. I do know on the woodward fuel system the butterfly will track with KOEO but Nissan will not ( please correct me if i am wrong). I do know if the system has eco/power selection that you will get only 30% throttle read on service screen in eco mode. These are pretty simple systems to figure out but it makes it so much easier to diagnose if you are there hands on and doing the diagnosing. Language barrier with yangsteven doesn't help but we try ey?

Thanks for all, my friends

Tomorrow, i will try make some calibrations to the throttle body, as in the moment, i dont have the software and scanner for review, cant access to information of the ECU. If the problem is not solved, i contact with a caterpillar or nissan technician.

I didn't know about legal implication of shared this information, sorry

yep, there are 2 connectors underneath the cup holder
a small black square one for the diagnozer cable, and also another larger OBD connector , they are usually wrapped in blue tape.(this is on late tier2 and later models, tier 1 the diagnozer connecter is on the ecm behind the right foot step cover)
Now as far as testing the TBS against the PPS both should progress relativly together with both reaching the 100% mark when the PPS is fully depressed. Most of the time when there is an issue with the TB sensors it will not achieve the 100% mark due to linkage binding or lack of lubrication which leads to the binding inside the box. This would ultimately keep the TB from reaching its expected position and the % range would be anywhere from 30% to 70% which is till not enough when using diagnozer. I have tried removing the cover and lubricating the mechanism and gears inside and cleaning the butterfly and chamber but to no avail the TB would ultimately fail with only a small amout of 'borrowed time' after the attempt. Replacement was inevitable even after the repair attempts in the long run.
You can try cleaning it if you like but i'm afraid you will be replacing it shortly down the road as it will start coding out again sooner or later.

and like as been said, passing out manuals is not my first choice due to the legal ramifications behind doing so. If forum users would read the TOS here they will also come to realize that this site does not condone it either even thought it happens. I'm not prepared to be made an example of either... sorry. I'll help you any way i can other than that ;o)


good luck

If you have a better quality OBDII code reader you can even look at some of the engine data such as throttle angle and such,mine I use is an ACTRON Is one of the better ones they sell model 9175 or something like that.......I use it to clear codes and I can use it on some Trucks with the K21/25 engine to look at engine parameters while it's running,not all trucks will do this but have found some that will

The OBDII connector should be located under the cup holder,pull it out and will find it taped to the wiring harness.

Lately as more manufacturers are cracking down on trade secret info and I living in the law suit country known as USA, I will not send any printed material to another but i can tell you that the main lpg injector is is PWM and with injector removed and GLP purged from system that injector should pulse when unit is turned over with starter. But you said that ETC would close when when depressing the accelerator pedal which tell me something is wrong with either the ETC or accelerator unit. Not sure if this unit has OBD2 connector which can give the EPA P code I inquired of in earlier post. If it does, possible it is located under dash panels/ dash wiring. Perhaps Swoop can chime in and can give you some areas to look for the generic scanner connector on this unit if equipped.

RCAV8TOR Thanks for yours recommendations, take this into account

RCAV8TOR and swoop223, any of you have the technical manual of this machine?

The throttle butterfly should sweep from about 70 to 80 degrees open then close and back open approx 1/4 when key switch is cut off. if throttle isn't sweeping when cutting key off and is giving e-23 then you have a possible ETC that has gone south. As i said earlier, this might be a job best suited for a CAT dealer as parts could get costly in a hurry. Let me repeat that. COSTLY! This problem is not for a parts changer as an injector holder can be as high as 1000.00 US. With proper software and interface, the dealer tech can check sensors and make quick diagnosis of unit. What we really need to know is the P code to narrow things down even further. With PC a tech can compare accel angle to throttle angle, fuel pressure reading, engine timing, stoichiometric mixture mass airflow voltage, O2 readings ect. Good luck and let us know what you find.

thanks for the information, the monday, i will go to make this test and define if problem is solved

this code E-23 is for the throttle sensor
this sensor is inside the throttle body
what is happening is when you turn on the key the ecm automatically sends a check signal to the accelerator and throttle body circuits to check them. This is what you hear when you turn on the key, you hear the throttle body calibrating or checking itself against the accelerator sensors to make sure all is ok. If during this check mode the ecm see's any of the sensors in the throttle body or the accelerator being off it will set the code E-23 and put the truck in limp mode and the dash MIL light will turn on.

If you have already checked the wires at the throttle body connector and they are good then run some calibrations first before replacing the TB.

There is a hpk document out from mfca about this code
it says to run the following 3 tests
Accelerator Released Position Learn.
Throttle Valve Closed Position Learn.
Idle Air Volume Learn ( TAS Fast Normal )

to do the accelerator released position learn do the following:
Accelerator released position learn:
a) Turn key switch to the ON position and count out 2 seconds.
b) Turn the key switch OFF and count out 10 to 12 seconds.
c) Turn the key switch ON and count out 2 seconds.
This learn is completed. You may key off now.

to do the throttle valve closed position learn do the following:
Throttle Valve Closed Position Learn:
a) Turn the key switch ON and then OFF.
b) Count out 5 seconds after turning the key switch.
c) Listen for a movement sound at the Electronic Throttlebody. It must operate.
If so, this learn is completed.

next the Idle Air Volume Learn needs to be done (this can only be done using the diagnostic program from laptop).
Air Idle Volume Learn (Fast TAS Normal)
a) Open diagnostic program version 3.1 or higher.
b) Start the engine and let it warm up to 76 to 84 degree C.
c) In the diagnostics program select model.
Select Connection: VCM1 and then
Select Target : ECM.
Select Active Test: Page 1 will open.
This will be identified with Fast TAS Normal.
To the right of the screen push the EXECUTE button.
The ECM will perform a self learn. It should complete in 15 seconds.

If this does not fix the problem and the code returns you should replace the throttle body. DO NOT try and repair it, replace it!

good luck

Hello RCAV8TOR.

i checked some important wires and connector, fuses and relays and are well, When the key pass of on to off position, the throttle rotates slightly

Hello Friends, Thanks for your answer. The display show the code e-23.
the serial number is AT3500048


The past thursday, i tested on the machine some things,

i retired the pipe that go of the air filter for see the behavior of the throttle acelerator, and try starter the motor, when see of surprise the motor run, but i should drop the pedal of acelerator for that the motor follow running, when i drop the acelerator pedal, the throttle too is go to close, and the motor is off.

i was Making some attemps, but the motor is ON only for five seconds, i was think that had a problem with the low revolutions, and in the vaporizer i looking for the duct of low rpms, but i dont find this

Then i revised the reductor and find a valve near of the injector, and i think this control the gas that get into the motor at low rpm. I measure the voltage in the wires of this valve when the key is ON position and have 12 volts, but when i connect the valve the voltage drop to five volts, i retired this valve of the motor and see it behavior, when the key is ON position the solenoid is atracted and when the key is OFF position the solenoid is released, some times the solenoid not is atracted although the valve have five volts.
How works this valve?

I have other question, when the acelerator pedal not is push, the throttle should close?
I was think that the body throttle work how to carburator on gasoline car, but i detailed that the duct dont have any holes, then this throttle is with a valve, control the pass of glp and air, this is right?

What do you think about this? i dont see what is the problem

Thank for all and sorry for my bad english