Archived Help me!! Can't safely drive truck..codes P0642..and

[TheWolf]

Sorry it is long, but hard to explain



Here is the problem. . was driving the truck a couple weeks ago and it started acting up. was running smarty at the time. truck started bucking and not taking throttle. went back to regular stock software and it acted the same. Thought my lift pump went south.

I have codes P0483 fan speed

P0642 sensor reference voltage 1 circuit low

Drove it today to my grandmothers garage to try changing lift pump, and figured out a little more on how it is acting. It will start and idle fine. But, if you give it throttle it will actually cut the engine out a bit. If you hold the pedal down for a few seconds then it will eventually take some fuel rev up to around 2400rpm and then fall off again. Here is the kicker. If you just touch the pedal ( i mean just touch it enough to very slightly move it) it will take off and rev to around 2400 rpm and take fuel as if nothing is wrong, except it will rev by itself that high with the feather touch of the pedal. Pedal position is probably where you would be normally be around 1000 rpm, but goes to 2400.

I tried unplugging the sensor on the air filter intake to see if it made a difference but it did not. just gave me 2 more codes.



Can anyone help me figure this out and what is the P0642 code??

Thanks in advance

 

[Missouri Mule]

Seems to me that you need to check out all sensors related to the engine running. You would need to check the input and output since it doesn't state which one is low.

The input if it is like the 12 and 24 valves should be 5 volts (supplied by the computer). The output would be less. You mite have to research the voltage for the out putof the sensors.

The map, crankshaft/camshaft, crank speed sensor, Apps maybe even your coolant temp sensor. I'm not sure which others you would have on a 3rd generation.

A multi-meter is what you need to use.



Of course I could be way out in left field.

 

[JApol]

P0642 is popped with 2 conditions.
Low Voltage at #2 sensor supply circuit
Sensor reference voltage 1 circuit low.
Let me do some looking and I will repost with what I find

Sensor Reference Voltage 1 circuit low -Gasser
Low voltage at #2 sensor supply ciruit - Diesel and fan related.
This is some hard troubleshooting.
Did Code P0483 set?
yes> replace fan clutch.

 

[TheWolf]

yes,

P0483 fan speed was the other one to show up. But, I belive I had that show up before with my TST when I first got it.



So possibly look toward the fan clutch?



Thanks for your help so far.

This seems to be puzzling eveybody. No one has seemed to come across this before.



If/when I find out the problem I will post it. Any other ideas??

 

[JApol]

another part of the trouble shooting was to makesure all aftermarket wiring was correctly installed but I didn't put that down since the other code popped also.

 

[TheWolf]

Well, it is completely stock right now. Sold TST and getting newer one with adjustable settings(has been off truck for a month or so). Smarty is set back to stock. It happened when smarty was loaded.

 

[blacksheepdiesel]

Did you read codes with key on/off cycle or with the Smarty? Sometimes codes show up on code reader when they don't show up on odometer readout.

Accelerator pedal position sensor? Find a buddy with same year and transmission as yours and swap his APPS for yours and see what happens.

Godspeed,
Trent

 

[TheWolf]

thought about apps , but wasn't sure how to test that.





Read codes with smarty, not key cycle



Are there any known apps to go bad or reason. Would the decreased tq mgt of the smarty cause any probems with the electronics with the apps?

I guess mine is under the battery(it is not mounted on the intake horn)

 

[TheWolf]

update,

Just got off the phone with the service center. It turns out the fan is shorted. they came up with a code for 5 volt reference signal(dont know if it correlates to the circuit 1 low voltage code for sure. But, if it is unpluged the truck runs normally. Can't really drive it like that though.

Heres the kicker, the fan runs around $350 and is not in stock(backorder?) for them to order. It says may be available in a day or two though. If not does anyone know of something aftermarket that wi work and plug into the factory harness and mount correctly?



Thansk for your help

 

[Missouri Mule]

TheWolf, do the 3rd generations have a electric fAN or electric thermal viscous fan drive?

 

[TheWolf]

MM

Sorry, not sure, the service dept just told me it was the fan shorted out. Motor was probably bad . Just called them back and told them to order me a fan, hopefully it will not be long. I can try to remember to ask them about it though.

 

[Elite1]

update,

Just got off the phone with the service center. It turns out the fan is shorted. they came up with a code for 5 volt reference signal(dont know if it correlates to the circuit 1 low voltage code for sure. But, if it is unpluged the truck runs normally. Can't really drive it like that though.

Heres the kicker, the fan runs around $350 and is not in stock(backorder?) for them to order. It says may be available in a day or two though. If not does anyone know of something aftermarket that wi work and plug into the factory harness and mount correctly?



Thansk for your help

Wolf, I also had to replace the fan motor, it now runs great! I guess something was shorting out and causing the same codes and surging. Thanks to you (and TDR) I had something to go on. The Cummins dealership said they would have never thought to look there. I unplugged the lead which hangs down near bottom of radiator (like you said) and she ran fine... Thanks for posting your problems and solutions, it saved me a lot of time and agrevation, in trouble shooting the problem.



Regards, Marty