New truck has some codes

[DavidC]

I just bought another 2001.5 2500 this one is 4X4. The check engine light has come on a few times. When I do the key trick it gives me PCU P0622 and P1765, ECU P1693 (companion code). Any ideas would be greatly appreciated.

[Mopar1973Man]

P0622 Generator Field Not Switching Properly An open or shorted condition detected in the generator field control circuit This is caused by either a wiring issue or bad brushes in the alternator. It best to have the alternator removed and bech tested. Then if the alternator failed then just rebuild it... P1765 Trans 12 Volt Supply Relay Ctrl Circuit Current state of solenoid output port is different than expected (4-speed auto. trans. only).Well I can't answer that one too good but i'm sure some our trans gurus will be able to help ya...

[DavidC]

Thanks Mopar, The trans has a BD pressureloc module on it. I don't know if that may cause the tranny code.

[Wild and Free]

Thanks Mopar, The trans has a BD pressureloc module on it. I don't know if that may cause the tranny code.

Yes it does due to the fact that the relay is removed and terminals are jumped instead. I too have a pressure lock that I am going to remove due to issues I am having with it. Plus I feel it is redundant due to already having a better valvebody.

[Wild and Free]

My rig has had the p 0622 code since I bought it with 18k miles on it in 02 and it is always there and comes back the instant it is started if cleared, it has never been an issue. 7 years 110k and counting. Neither of those should cause a CEL.

Edited December 22, 2009 by Wild and Free

[DavidC]

My rig has had the p 0622 code since I bought it with 18k miles on it in 02 and it is always there and comes back the instant it is started if cleared, it has never been an issue. 7 years 110k and counting. Neither of those should cause a CEL.

I am just figuring out the stuff on this truck. My other truck does not have the Pressureloc and I was wondering what your oppinions are on it.

[edcasey]

These codes are actually related. The auto transmission relay is closed by the same circuit from the PCM that also powers the alternator field. Take a look at this diagram.

The PCM uses this circuit to regulate the alternator and close the transmission relay. So you could have a problem in the alternator, wiring from the PCM, the PCM, or a trans relay short. You will need to test the circuit for voltage to find the problem.

When the transmission relay doesn't close, the overdrive solenoid, governor solenoid and torque converter lockup solenoid aren't going to energized. The transmission is than in limp mode and will "stick" in 3rd gear. Driving the truck in limp mode will cause wear or damage to your transmission. You wont experience limp mode if the 1765 is intermittent.

If your transmission does go into limp mode, you can remove the relay and use a jumper wire between slots 30 and 87 as a temporary fix. I carry a jumper wire with male spade connectors in my tool box just for this purpose. It saved me a tow bill last year.

[Wild and Free]

He has a BD pressure lock and the install of that requires the removal of the trans relay and the terminals have to be jumped for the operation of the pressure lock. As for his question on the pressure lock I feel it is not neccesary in my case because I already have an aftermarket valve body which increases internal pressures in the tranny. Th Pressure lock is designed mainly for stock tranny and its purpose is to stroke the servo valve earlier, when the throttle is at 30% the servo should be stroked to what would be 80% throttle travel. thus increasing tranny pressures sooner than would be normally, Some tranny shops actually have setups for the BD pressure lock to operate off of boost pressure for high performance guys instead of the electric over vacuum like it is designed to work from. Hopefully I didn't cornfuzz ya too bad.

[edcasey]

He has a BD pressure lock and the install of that requires the removal of the trans relay and the terminals have to be jumped for the operation of the pressure lock.

See what happens when you don't read all the replies. I completely missed that you have a pressure lock. Thanks Wild.

[DavidC]

Thanks for all the input guys. I haven't been around for a week so I just got a chance to recheck my post. This weekend I'm going to go through all the electrical and check all connections. As far as I can tell who ever did the work on this truck didn't take as much time making nice connections as I would have, but then I'm an electronics tech by trade and tend to do all my wiring a little to well.