Get some video! It sounds like a Bang Up job!

 

Looking good


P1652 code is "IAC Monitor Disabled by PSP Switch Failed On" in case you haven't found it yet.....

 

Dude that is friggin' SWEET!

 

nice job... I've shown many friends this thread... they all give the big thumbs up!

 

Does this apply though? (no power steering pressure switch on a diesel) Both the smarty and the DRB scanner said P1652 was "J1850 short to ground".

Somewhere in a dodge manual the dealer had (not in my service manual) it said for this code to check the resistance between the J1850 circuit in the ECM harness and battery negative. If it wasn't less than 10 ohms then replace the ECM. If it was less than 10 ohms, then measure between the J1850 ciruit and all the other circuits in both connectors. If resistance was greater than 100 kohms refer to the body diagnostic book communication section, if not greater than 100 kohms, repair the J1850 shorted to another circuit.

The real issue was that no where is the J1850 circuit described or labeled? I don't have any idea which wires these are, so I can't check the resistances. I don't have any clue what the J1850 circuit is used for?

Any ideas?

 

P1652-J1850 SHORT TO GROUND




For a complete wiring diagram Refer to Section 8W.

When Monitored:
While the ignition is on.

Set Condition:
The ECM detects a short to ground on the J1850.

Possible Causes
ECM
(D25) J1850 SHORTED
COMMUNICATION


Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

Diagnostic Test
1. ECM

--------------------------------------------------------------------------------



Turn the ignition off.
Disconnect the ECM harness connectors.

NOTE: Check connectors - Clean/repair as necessary.


Measure the resistance between the (D25) J1850 circuit in the ECM harness connector and battery negative.

Is the resistance less than 10 Ohms?

Yes
Go To 2

No
Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)



2. (D25) J1850 SHORTED

--------------------------------------------------------------------------------



Measure the resistance between the (D25) J1850 circuit and all other circuits in both ECM connectors.

Is the resistance greater than 100k ohms?

Yes
Refer to the Body Diagnostic book Communications section.

No
Repair (D25) J1850 shorted to another circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)

 

message too short to add attatchments!

 

Awesome, thanks for the info. Exactly what I needed.

I'll have to do some checking tomorrow and see if I can correct it. I don't believe I even need the PCI bus for anything in my case.

 

Did some thinking on the info posted above. On my engine circuit D25 goes directly from the ECM connector to connector C108. I wired this to the dataport inside the truck. That's the only place is goes. So during normal conditions, it isn't connected to anything. The ECM expects it to be connected to all the other devices on the PCI bus. Not sure why the code would say shorted to ground, may it actually means no communication present? The wire is open ended, just floating (no voltage or ground present). I just ran out and checked the resistance from this point (dataport) and ground and got 5 M ohms (so no short circuit is present).

I wonder if this code hurts anything? limp mode or ???

 

Well vzdude has really got you covered maybe he has some insite on this?

 

I don't think it will cause you any trouble. Like the diagram says, it is basically for communication woth other modules, and I'm guessing you aren't doing that in yer Ferd! LOL The only thing that concerns me, is that according to the diagnostics, if there isn't a short to ground ( like the code indicates ) then there may be a faulty ecm. That would be the only thing to "raise my eyebrows".

 

Did some digging in the service manual and found out the PCM is the dominant node for the PCI bus, therefore it would normally terminate the bus through a 1 KW resistor and a 3300 pF capacitor. The ECM doesn't see this and is throwing the code (I think). I'm going to terminate the PCI bus like it says in the manual and it should make it go away.

The only other codes I have are related to the fuel level signal. It is expecting a resistance from the tank level sendor and doesn't have one right now. I need to find out what the resistance range is supposed to be and install a resistor from this location to the sensor ground to clear these codes.

Also noticed in the wiring manual that the fuel heater is always supposed to be on. I figured it only came on when needed, but per the wiring it is on when ever the key is in Run or Start. I currently don't have it hooked up yet.

 

You're doing all that in your driveway? Nice job...

 

Yeah, wasn't easy. Engine hoists don't like to roll on the gravel so I just rolled the vehicle forward once it was time. Here's a few more pics...

 

I love that first pic!!!!way to make it happen with what you got!!