Bought an used 2500 Ram van about a month ago. Great van! Just started to stop running after driving about 5 miles or so. Scanner code 433 (purge solenoid). Checked vacuum lines(good) Checked voltages(good) Replaced the solenoid. About a day later the engine light would come on, relays started clicking and the engine dies. No scanner codes. Checked buss voltages (5volt and 2.5 volt) good... Checked sensor supply 8v good. Replaced crankshaft sensor on recommendation of mechanic. Ran good for about 15 miles and same problems started up. It seems that after the van cooled a while, it would start again. Replaced cam position sensor and ran good for a day, same results. Discovered today that the gauges do not work after the ignition key is turned to run position. If I wait a few moments, they will jump to their positions and the van will start. If they do not jump to the position of correct reads, the van will not start. I tried shaking the wiring harness and I do get the van to start(after the guages read right). I was told my PCM is bad, but could be a wiring problem.. Any ideas? Intermitten problems really bug me. Still get 0 scanner codes. Is this fixable or should I cut my losses?

 

The clicking relays are a telltale sign that it's your PCM going/gone bad.

 

mechanic stated the clicking relays could be caused by intermitten short in the wiring. How can I check the PCM for worthyness. They put on a great diagnostic scanner and couldn't find a fault with the PCM, but didn't come out and rule it out either.

 

Well I'm not there and your mechanic is. What I can tell you is, other people that have had the clicking relay issue solved their problem only after replacing the PCM.

To me, if it were a shorting/wiring issue you would be able to make the van stall or the relays act up on command simply by wiggling the wiring harness. Also, since letting the van cool down allows it to start, this would also rule out a wiring issue as the problem.

 

I agree with the wiggleing wires to "force" the problem... tried that and no difference. I decided to replace the PCM. After that, the van would start rough and idle bad and finally die. Now it doesnt start at all. Still no codes. Checking this time at the fuel pump, I found NO 12v. Trying to trace back to the fuel pump relay, but can not find it. No where the book/manual shows and wonder if the 2000 van did away with the fuel pump relay. If so, where is the 12v source to the fuel pump come from... thanks

 

Do the relays still click with the new PCM?

Is this a new, rebuilt or used (junkyard) PCM?

Are the part numbers from the old and the new PCM identical?

 

PCM is rebuilt and programmed for my VIN and mileage. Relays do not click anymore, don't have a chance to, cause I cant get the van to run. The clicking I used to get was after running for a while and then the engine light comes on with relays clicking and then the engine died. That problem was way back when.....
In fact...with the rebuilt PCM, I get new codes about the transmission which I never got before. I'm wondering if I got burned with the rebuilt PCM (on-line firm from Fla)

 

BTW... do you know where the fuel pump relay is located???

 

Why yes I do.

 

I anticipate that your next thought is, "okay, where is it smartass?"

It's in the interior fuse box at the driver's end of the dash. Check the cover for the index after you pull it off.