Hey guys I have a 5.5 gen 2003 Maxima 6sp that keeps blowing a fuse. Let me start by naming the mods. It has Cattman headers and y-pipe, a vafc-2, and 02 simulators.

The car will start and drive fine. However, when I go to start it up again, it will start and immediately die. I will then replace the fuse and the car starts and drives fine again. But basically everytime I drive the car the fuse blows. When the fuse blows, the car still drives, it just wont start again til i replace it. I notice that the fuse wont blow when im just starting it and driving it around the block, but if i get on the highway, it will blow.

The fuse that keeps blowing is the Under-dash 15 amp fuse labeled # 20 on the fuse box. I've searched and looked up the FSM, but can't seem to find exactly what else is on this circuit. My initial thought was the Vafc-2 but the car has been running mint with this on for over 2 years now.


When the fuse blows and the car wont start, i trip the 2 codes for the immobilizer P1800 and p1601. But i think i am tripping these as a result of the blown fuse.
I think i have a short somewhere, but i want to try and rule out everything one at a time. Has anyone dealt with a problem like this before. Can anyone tell me what components feed off of underdash #20 "ENG CONT" fuse? Is my problem definitely a short, or could it be a faulty component such as the immobilizer system or the 02 sensors.

 

If you have the Nissan FSM, go to page 11 in the EL section. This is the power routing diagram of the electrical system The page is printed in landscape mode, so when you rotate it to be able to read it, fuse 20 is in the lower right corner. Beneath that is a box with the names of FSM circuit diagrams where Fuse 20 is shown.

These diagram names are not in the index, so you have to try to intrepret them. You can usually guess what circuit the diagram is.

For Fuse 20 it shows VENT/V, BYPS/V, COOL/F, VIAS/V, VIAS, START and NATS.

You may have a wire that has rubbed through the insulation? But the fuse blowing only on higway driving kinda rules that out. Something that has to work more at high engine rpm. Unfortunately I don't know what to suggest.

 

thank you for the reply. any idea on how to test the NATS system or the VIAS or any other idea what vent/v byps/v cool/f vias/v are?. could it be possible that it is only blowing on the highway because the car is shaking enough to cause the wire to ground out and it doesnt ground out in just driving around the block.

 

I looked up the disgram names in the index and they were in there! Here's what they stand for and the page in the FSM where they can be found.

When there are multiple page numbers, it is because the part referenced can cause multiple DTC codes.

VIAS - Variable Induction Air Control System - EC 678
VENT - EVAP Canister Vent Control Valve - EC 370, 558, 567
BYPS/V - Vacuum Cut Valve Bypass Valve - EC 594, 601
COOL - Cooling Fan Relay # 1 - EC 519
START - Starting System - SC 11
NATS - Nissan Vehicle Immobilizer System (NATS) - EL 362

The VENT and BYPS are part of the fuel vapor control system. These particular parts are located by the driver's rear wheel and take a hell of a beating from road debris and water and worse if you are up north in the snow belt.

 

funny...Im having the same fuse blow over and over too...but mine is the ENG CONT 1 fuse 15A under the hood on the drivers side near the wheel well. Did you ever find out the problem??? That would help me out. Im throwing TPS codes after it blows but I dont think thats the problem.....TPS is not even on that circuit.

 

That is not the same fuse...