P1689 Code
Record Breaker
Joined: Jun 2008
Posts: 1,970
Likes: 20
From: Clermont, Florida
It means "No communication between the ECM and the fuel injection pump module." It also means there is a data link cicuit failure between the fuel injection pump module and the ECM. You probably have a bad fuel pump. You can get a fuel pressure testing gauge kit cheap at Harbor Freight to test the fuel pressure for sure.
On a 2001 with the 3.9 you should have between 49 and 54 psi at idle. When you shut the truck off the pressure should not fall below 30 psi within 5 minutes. If it does, the fuel pressure regulator is bad (which is what was wrong with my truck). I also have a 2001, 3.9 and 5 speed manual, and I just replaced my own fuel pump 2 weeks ago. It was not the easiest job to do by myself but it wasn't too hard either. My new fuel pump was $225.00 at Advance but I had a 20% off coupon so I paid like 180 and did it myself. I hear it runs about 450 to 600 to have it done so I was glad to be able to do it myself.
Jimmy
On a 2001 with the 3.9 you should have between 49 and 54 psi at idle. When you shut the truck off the pressure should not fall below 30 psi within 5 minutes. If it does, the fuel pressure regulator is bad (which is what was wrong with my truck). I also have a 2001, 3.9 and 5 speed manual, and I just replaced my own fuel pump 2 weeks ago. It was not the easiest job to do by myself but it wasn't too hard either. My new fuel pump was $225.00 at Advance but I had a 20% off coupon so I paid like 180 and did it myself. I hear it runs about 450 to 600 to have it done so I was glad to be able to do it myself.
Jimmy
Record Breaker
Joined: Jun 2008
Posts: 1,970
Likes: 20
From: Clermont, Florida
P1687 means the PCM is not communicating with the instrument cluster. Makes me wonder if the cluster is bad and the fuel pump is OK. I don't see how both could fail at the same time. Is the truck running? And is the cluster and the fuel gauge working OK?
Jimmy
Jimmy
Thread Starter
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Registered User
Joined: Dec 2009
Posts: 34
Likes: 0
From: Raywick, KY
The truck is running and everything seems to be working fine. I did have the dash apart to hook up my sub to the cd player. I may have pulled sumthing lost a little or something cause nothin seems to be wrong now. Im gonna reset the codes and see if they come back. Thank for the help.
