Hello,

One morning Disco would not start. Took the battery to auto zone, and turns out it was bad. After replacing the battery, truck started but had these 8 codes:

P0414
P0445
P0448
P0102
P0340
P1884
P0134
P0154

I cleared the codes, but they come back pretty quick..
The car starts, but does not start smooth like it used to.

Does anybody have any ideas? My Maf is about 1 year old.

 

P0414 SAI vacuum solenoid valve short circuit to ground

P0445 Purge valve short circuit to ground

P0448 CVS valve short circuit to ground

P0102 Mass or volume air flow low input MAF signal < minimum threshold, which is speed dependent

P0340 Camshaft position sensor circuit malfunction Open/short circuit to vehicle supply or earth

P1884 CAN message from tranny - multiple codes

P0134 O2 sensor circuit no activity detected (bank 1, sensor 1)
Front sensor LH bank open circuit

P0154 O2 sensor circuit no activity detected (bank 2, sensor 1)
Front sensor RH bank open circuit


OK, you are running lumpy because the ECU can't get current signals, and is depending on stored estimates for things like cam shaft position. And fuel mpg will be stinky also. From all the codes it sounds like you have a melted, grounded, skinned, rubbed, naked wire harness in one or more places. If you have any aftermarket mods, check those wires too, some fools don't fuse, and when something overheats it can fry other wires all over the harness.

Or at the ECU, the connectors are full of water and corrosion.

 

OK, I checked and saw that fuse 2 was blown. Replaced it, and cleared codes. Everything was running fine, but the fuse blew again right about the time that I would hear the sai pump turn on. Could a bad sai pump be drawing enough current to blow the fuse?

For now, I have removed the sai pumps plug to see if that stops the fuse from blowing.

 

Check for bare wires going to all of those components listed: All 4 o2 sensors, MAF, evap pvc, CMP (its right behind the crank pulley), and your sai solenoid, ignore the 1884 it'll go away when you find the issue. If you don't find any bare wires then start disconnecting each component until the fuse stops blowing, when you do you probably have the culprit. I had the same exact issue (fuse 2 kept going poof) and it turned out I had a bad cmp. When disconnecting, all codes went away (except the cmp of course) and fuse stopped blowing.

 

Fuse 2 under hood powers up a lot of things. You may have to use the electrical manual and circuits diagrams, and follow each wire and find connector number and unplug that. The SAI air pump actually does not get power from that fuse, it comes from FUSE LINK 2 (not same as a fuse) thru a relay.

Fuse 2 powers the O2 sensors, the MAF, and the evap canister vent, and more. O2 sensors are easy places to have a wire melted and grounding out. Shake the harness.

 

Did your fuse blow the minute you started your engine? Or did it blow after driving around?

 

I guess I'll plug that back in then. In order to rule out which one of these components could possibly be causing the blown fuse, I'm gonna unplug them 1 by 1 as suggested.

Would the fact that the fuse blew after driving around 2 times rule out certain components? I would think that if it were a component that is powered immediately when the car starts, the fuse would blow right away.

If this is the case, then should I start with unplugging the sai solenoid? I did a quick look over of the harness, and did not see any damaged wires at first glance.

 

No, you could have a device that powers up first thing, but is drawing way too much, just not enough to blow fuse. As other things come on later, they add up and pop fuse. Or you are starting out with 105% of fuse amp rating, and it just takes longer to melt. An amp meter would be helpful, but unplugging will help narrow it down. Start whereever you like. But I advise having a RAVE schematic to help you along.

 

Found the problem. I have the wiring harness came loose and was barely touching the edge of the passenger side exhaust manifold. Re-secured it and taped it up real good, but now everything back to normal. Thanks for the tips guys.

 

I'm dealing with same situation. My oil light came on, I checked the oil pressure and that is fine, plenty of oil pressure. So I replaced the oil sensor switch, the light went off for a day then came back with all the codes that alias j had and fuse #2 keeps blowing just by turning the key on. I've searched for the short, I can't find it. I'm thinking that the oil sensor switch wiring maybe the problem. Does fuse #2 connect to the oil sensor switch? What parts of the truck work with fuse#2? Where can I find a wiring diagram for that fuse? Thanks in advance for your help.