Hello,
I have a 2000 Dodge Ram Van B3500. It needed a new PCM (which I replaced myself after local Dodge dealer quoted a thousand dollars to replace it).

That mechanic diagnosed the need for a new PCM because no codes were returned, the PCM gave no response, the 5-fold signal checked OK, and the power/ground to PCM checked OK.

After installing it I took it for a short drive. It seemed to run great (it wouldn't even start before I replaced the PCM).

Only one problem... now the Malfunction Indicator Light came on. Any suggestions of where to go from here?

Thank you all for your help!

 

A MIL light? On the new Ram Vans from 1998-2003, the MIL is displayed in the odometer display. Maybe the check engine light is on???

Have you tried the key-dance of three off/on to get some numbers?

 

Have you pulled the codes from the system? With the lamp on the PCM has sensed a problem. Have your mechanic pull the current code(s) from this unit.

Did he/you get the proper PCM? If the part numbers are not matched up correctly you may have the wrong PCM, and it may sensed that there are things it should or should not control that sees a problem with. Example would be putting an PCM that controls OD on the transmission and hooking it up to the wrong transmission/engine setup.

 

According to our owner's manual, it's the MIL lamp.

What is the off/on key dance?

 

With in 5 second do this with out starting the engine: key on, off, on, off, on and read the odometer on your van for the codes.

If that does not work try: key on, off, on, off, on, off, on.

 

Mobile Auto Repair:
The part #'s match exactly.

Thanks for explaining the off/on. It took a few tries, but finally gave us the following numbers in this order:

P 0443
P 0753
P 1765
P done

I hope the above doesn't mean the van will disintegrate to ashes by morning !

 

Nope the van won't disintegrate tonight.

P0443 1T: EVAP Purge Solenoid Circuit Fault Conditions: Engine started; system voltage over 10v, EVAP Purge solenoid commanded ON and off, and the PCM detected an unexpected voltage condition at the EVAP purge solenoid for 3 seconds. Note: The solenoid resistance at 68°F is from 25-35 ohms. Possible Causes: EVAP purge solenoid control circuit open or shorted to ground EVAP purge solenoid power circuit open EVAP purge solenoid is damaged or it has failed PCM has failed.

P0753 1T: A/T 3-4 Solenoid/Transmission Relay Circuit Failure Conditions: Key on or engine started, and the PCM detected an unexpected voltage condition on the 3-4 Solenoid control circuit during the test. Possible Causes: 3-4 Solenoid control circuit is open or shorted to ground 3-4 Solenoid is damaged or has failed Transmission relay power circuit is open (check the fused B+) Transmission relay is damaged or has failed PCM has failed.

P1765-SWITCHED BATTERY

POSSIBLE CAUSES
INTERMITTENT WIRING & CONNECTORS
2C PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
4C PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
L/R PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
OD PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
UD PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
TCM- SWITCHED BATTERY

 

I might be in over my head here...but what would be my next step?

 

Since you have to ask, I guess my answer would be, "making a repair shop appointment."

 

Hi all, and thanks for your help.

This morning I disconnected battery and PCM then reconnected all. I took her for a spin and did the key dance. Only came up with one code this time: P1765.
Thinking it may be a fluke I disconnected/reconnected again, took a spin and same thing: only P1765, switched battery.

Can anybody explain to me what switched battery means? I googled it, the most clear answer I found was 'This code is set if the Transmission Control Module senses voltage on any of the pressure switch inputs prior to the TCM energizing the relay.' (justanswer.com)

I know that I'll eventually have to make an appointment with the shop, but I'm the type of guy that wants to research as much as I can before going in...

Any guess what the mechanic will want to do to fix this? Is it a wiring problem? A bad sensor?

Thanks again for all your help!