Hey guys,

Wife told me yesterday that the CEL was on in our '03 DGC again. Went out to have a look and the only code displayed on the ODO is P1684. Did a bunch of reading and the common consensus is that the "battery disconnect" code should NOT cause a CEL.

Is it possible that there are other codes that an actual scanner would show that the "key dance" wouldn't show on the ODO?

As far as recent maintenance, replaced all 6 spark plugs ~2-3 months ago. Oil & Filter change ~1 month ago, as well as an air filter at the same time.

Van seems to be running good otherwise. No obvious problems anyway..

 

It could be a transmission code,which will not give a code unless you use a scanner on the TCM. The only code you will get on the ODO is P0700 for a trans stored code.

 

She drove it for a few hours yesterday and the light has gone off again. Not sure what's up, but hopefully I can get my hands on a scanner ASAP.

 

Haven't had a chance to get my hands on a scanner yet, but the CEL has been coming on for a few days, then off for a few days, for the past few months. No codes at all except for the P1684 still. I put a new battery in yesterday, but the CEL is still on as of this morning. I'm hoping this time when it goes off, it'll stay off, but I'll keep you guys posted.

 

P1684 is a transmission code, loosing B+ to the trans control module

Symptom:
P1684-BATTERY WAS DISCONNECTED

When Monitored and Set Condition:
P1684-BATTERY WAS DISCONNECTED

When Monitored: Whenever the key is in the Run/Start position.
Set Condition: This code is set whenever Transmission Control Module (TCM) is
disconnected from battery power B+ or ground. It will also be set during the DRBIII

Quick Battery Disconnect procedure.

POSSIBLE CAUSES

QUICK LEARN WAS PERFORMED
RECENT BATTERY DISCONNECTION
TCM WAS REPLACED OR DISCONNECTED
INTERMITTENT WIRING AND CONNECTORS
FUSED B+ CIRCUIT TO TCM OPEN
GROUND CIRCUIT OPEN

TEST ACTION APPLICABILITY

 

P1684 = tranny code? Makes sense. Used to indicate a power loss to the PCM. I believe the PCM and TCM were combined into the same box sometime in the 4th gens history. A battery disconnect is a definite power loss. Question still is, should it turn on the SES light? Wasn't disigned to on the 3rd gens, well I should say according to Haynes anyway.

 

Thanks guys!

Unfortunately I'm an idiot when it comes to reading electrical diagrams! I'm guessing B+ means the positive battery cable?

So can I just follow that cable backwards and make sure it's connected properly? One of the possible causes says "fused B+ circuit to TCM open". So does that mean it could just be a blown fuse too?

 

Going to revisit this problem on the weekend... could somebody answer my questions above?

I've since found the "B+" on the diagram.. so I think I kind of know where to look now..