Fan clutch po0480 dtc won't go away

[Wayne M.]

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I am not sure what year Bobs diagram is for, but assuming it's accurate for you, the line at left is where your concern is. It begins in the fuse box. There are splices (SXXX) and connectors (CXXX) along the way. The box at bottom should be the fan clutch connector itself. The 8W section in the Chrysler factory shop manual for your truck will list all the locations of connectors and splices with good accuracy. To repair the truck, the FSM is desperately needed.

 

[JBain]

I am not sure what year Bobs diagram is for, but assuming it's accurate for you, the line at left is where your concern is. It begins in the fuse box. There are splices (SXXX) and connectors (CXXX) along the way. The box at bottom should be the fan clutch connector itself. The 8W section in the Chrysler factory shop manual for your truck will list all the locations of connectors and splices with good accuracy. To repair the truck, the FSM is desperately needed.

Thanks Wayne, I guess I'll have to spring for a FSM. I checked all the pins on the fan clutch connector and at least I can get continuity with sensor ground to the negative. Bob's wiring diagram is probably correct in that the connector is the same 6 pin with pin 4 blank. Thanks, John

 

[cerberusiam]

Fair enough, if you don't want the benefit of chasing the same thing I won't bother since anything I say will likely be taken the wrong way. Carry on.

 

[JBain]

The saga continues. I have replaced the fan clutch with a mopar fan clutch. I Still have the P0480 DTC. I now have a FSM and have a question on a reference in the trouble shooting of the P0480. What pin is the Y1 driver circuit? If you have a 2004 FSM do a search on the P0480 in the power train section and you will find this procedure. They changed the names of the signals in the trouble shooting to confuse you. There is a couple of signals that match up but why can't they just say check from pin x t pin y?

"Measure the resistance between the fan clutch (Y1) driver circuit and the fan speed
(K4) sensor return (I got this one) circuit on the fan clutch assembly.
Is the resistance less than 10 Ohms?

Yes ! Replace the fan clutch.

See below for connector pin names.

#ad

 

[JBain]

I have also checked all wire for continuity between the ECM, fuse and the fan clutch connector and all are good. I think the Y1 circuit I referred to above is Pin 5 of the fan clutch connector??? If so then the procedure says the ECM is bad????

 

[JBain]

I have also checked all wire for continuity between the ECM, fuse and the fan clutch connector and all are good. I think the Y1 circuit I referred to above is Pin 5 of the fan clutch connector??? If so then the procedure says the ECM is bad????

 

[JBain]

Something more to add the fuse box cover says fuse 17 is the clutch fan it's not fuse 36 is as in the diagram that Bob posted.

 

[Wayne M.]

I think Bobs diag is for a newer truck with the different fuse panel/ TIPM. I seriously think you need to find C112. There should be a locator in the manual. I wouldn't condemn the ECM yet.

 

[JBain]

Wayne, you are correct Bob's diagram is for a different year than a 04 in the 04 diagram there is no connector just a straight wire with one splice. Like I said above, I have checked the continuity of all the wires and all are good. The "Y1 driver circuit" is the real question which pin is it?

 

[Wayne M.]

I don't have a power train section (!)
but what you're looking for must be what's called fan clutch control, pin 1 in the bottom box in the above diagram.

 

[JBain]

Thanks Wayne pin 1 makes since I didn't notice Bob's says fan clutch control and my diagram says something like park lockout. What a bunch of poor editing.

OK I think I have this solved not fixed yet though.

So if you do the trouble shooting steps, using pin 1, I get a bad fan clutch and speed sensor of which I have codes for.
The worst thing is this is a new clutch. My checks on the ECM indicated it was bad as well.

I think I know what happens with this.

1. The driver circuit shorts to the return in the fan clutch and thus over drives the driver circuit of the ECM.
2. The ECM driver circuit is then shorted to return.
3. When a new fan clutch is connected it shorts out the driver circuit on the new fan clutch.
4 You have another bad fan clutch.

I know you are thinking what about the 10A fuse. I wish it would have blown but I don't think it is even in this circuit don't really know why it's there.

What do you guys think?

 

[Wayne M.]

So you're saying pin 1 circuit is clean and no green from end to end? I would be poring all over the harnesses and pulling connectors apart and looking for chafing, etc.

 

[JBain]

I saying that all the wires check out for continuity but the resistance checks the FSM says to do indicate a bad clutch and bad ECM. When I say bad clutch I'm checking at the connector of the fan clutch not back towards the ECM. When I say bad ECM I'm checking from the engine side of the fan clutch connector to the ECM. When I did the continuity checks I had the ECM disconnected and checked each wire from the ECM connector to the fan clutch connector.

 

[Wayne M.]

Seems like things are getting obvious and serious. Good luck sir.

 

[PWong]

The saga continues. I have replaced the fan clutch with a mopar fan clutch. I Still have the P0480 DTC. I now have a FSM and have a question on a reference in the trouble shooting of the P0480. What pin is the Y1 driver circuit? If you have a 2004 FSM do a search on the P0480 in the power train section and you will find this procedure. They changed the names of the signals in the trouble shooting to confuse you. There is a couple of signals that match up but why can't they just say check from pin x t pin y?

"Measure the resistance between the fan clutch (Y1) driver circuit and the fan speed
(K4) sensor return (I got this one) circuit on the fan clutch assembly.
Is the resistance less than 10 Ohms?

Yes ! Replace the fan clutch.

See below for connector pin names.

#ad

I think pin 1 "fan clutch control" was the driver circuit, usually driver was the control signal.
Pin 5 was the 5V power supply circuit.
Verify for presence of 5V at pin 5, 12V at pin 6 and ground at pin 2.
Signal on pin 1 was a PWM signal, needs a scope to see the actual reading, might see some voltage reading on a voltmeter.

 

[JBain]

Thanks PWong, I got this figured out. The original failure caused the PWM circuit in the ECU to shorted to battery negative and now when a new fan clutch is connected it shorts it out and destroys it. Gone thru 2 fan clutches ouch. So I'm having the ECU fixed and getting another fan clutch. Hopefully this works.

The only question that keeps me wondering is why the 10A fuse? Shouldn't that have protected the ECM circuit???????

 

[PWong]

The 10A fuse fed power to fan clutch, not to ECM.
So it's protecting the fan clutch 12V circuit only.

 

[JBain]

The 10A fuse fed power to fan clutch, not to ECM.
So it's protecting the fan clutch 12V circuit only.

Yep that's my point why not protect the other circuits. I tore one of these apart and it's just a donut coil that all the wires go into. I guess some sort of magnetic effect thingamagig.

 

[JBain]

Well thought I would wrap this up since I don't have the P0480 any longer.

1. Found no broken or frayed wires.
2. The only thing bad was the fan clutch.
3. ECM was good.
4. Don't know what was wrong to still cause me to have the P0480.

Thoughts are:

The CTS is not very good at clearing codes.
Powering down and sending my ECM to SAI to find out no problem found cleared the codes.

My thanks to all for putting up with me on this.

 

[Wayne M.]

No problem!
If you're staying in the game, invest in AutoEngenuity PC based scan tool with the Chrysler add on pack. You won't regret it.
Long may she run.