2008 mustang gt

[Markv197]

Hi all, I've got a 2008 mustang 4.6 3v
I'm currently getting p0010/02 codes aswell as running rich on both banks / I've done an engine flush and oil change , new vvt solonoids /camshaft position sensors /new evap valve unit and this still hasn't resolved my issue , I've also found that my battery with the engine running is sitting on 12.7 v so I've now ordered a new alternator , but upon some more testing I've also found the fuse 20/21 from the passenger compartment have no power whatsoever , but the radio still powers on and the car still starts and drives , also , all the fuses that do work read the same as the battery (12.7v) which is odd as I'm sure they're not meant to exceed 12V, am I being hopeful that a new alternator will fix all my problems ? Has anyone had any experience with this ?

 

[Pentalab]

With a good alternator, with eng on idle, my 2010 with the 4.6L eng, reads 14.75 vdc right at the battery terminals. That's normal.
With eng off, and measured at the battery terminals, it read aprx 12.5 vdc.

Can you measure right at the alternator output ? You might have a bad ground connection in there somewhere.

 

[DieHarder]

Hi all, I've got a 2008 mustang 4.6 3v
I'm currently getting p0010/02 codes aswell as running rich on both banks / I've done an engine flush and oil change , new vvt solonoids /camshaft position sensors /new evap valve unit and this still hasn't resolved my issue , I've also found that my battery with the engine running is sitting on 12.7 v so I've now ordered a new alternator , but upon some more testing I've also found the fuse 20/21 from the passenger compartment have no power whatsoever , but the radio still powers on and the car still starts and drives , also , all the fuses that do work read the same as the battery (12.7v) which is odd as I'm sure they're not meant to exceed 12V, am I being hopeful that a new alternator will fix all my problems ? Has anyone had any experience with this ?

As Pentalab says running voltage should be 14.75 vdc (or thereabouts). Try doing some voltage drops with a VOM (on Volts DC) from the body (ground) of the alternator to the ground at the passenger strut tower (with engine running). If you're reading any appreciable voltage (more than a tenth or two) your grounds need work and/or you need new battery cables.

Here's a rundown from my experiences: Finally found the cause of my low voltage - Beware the all important grounds.

BTW, if you do get a new alternator, buy a Denso (2010?).. Much better compared to earlier years.

 

[Markv197]

Thanks for the reply ! I’ve used my VOM and continue to get the same low reading from different ground points ,that’s when I ordered a new alternator last week , I didn’t cheap out on it either , it gets delivered tomorrow, praying to god that it sorts all the issues I’m having out ( I’ve read on other forums that a bad alternator can be the cause of the p0010 codes because it messes with the pcm, it still doesn’t explain why I’ve got no power whatsoever in fuse 20/21 and yet my car and radio both still start up ???

 

[StockishS197]

Running volts should be at minimum 13.1-13.3 volts. Anything below that the alternator is suspect. Also, failed diodes in the alternator causes excessive AC ripple which commonly causes VCT codes, so I would also second replacing the alternator.

Both running volts, and AC ripple can be tested at most parts stores.

 

[Markv197]

Many thanks for the ideas and suggestions , I will let you know how it goes when my new alternator arrives , and should my new alternator come with any faults I’ll be sure to order the 2010 Denso one next time !

 

[StockishS197]

Many thanks for the ideas and suggestions , I will let you know how it goes when my new alternator arrives , and should my new alternator come with any faults I’ll be sure to order the 2010 Denso one next time !

Another suggestion besides the Denso, just get a NEW (not reman) alternator from a good parts store that has lifetime warranties. Mine has paid for itself many times over.

 

[Markv197]

Right , so new alternator installed and old connectors for it have been wire brushed and cleaned , it’s now reading 14.3 V , whilst installing the new alternator I did notice a ground wire at the bottom of the engine that wasn’t connected so I grounded it with a spare nut I had, the wire harness it was connected to joins the harness that connects to the camshaft position sensor on bank 2… so I have no idea if it has something to do with the old alternator or what it’s for… ?
But when I scanned my Carly it gave me codes 2198/2196 and 1000 (p0010)

When I cleared the obd and re scanned it only came up with 1000(p0010)
Not too sure why I got the other codes , battery had been disconnected for about an hour whilst doing the work .

 

[DieHarder]

If that's a ground it should not go there. I believe where you have it connected is one of the mounting points for a metal frame that was supposed to hold radiator hoses away from front of the engine. (Also been removed on my engine). If it is a ground it should be part of the harness that runs back to the negative battery terminal and passenger strut tower ground. If it's that ground it should run down the passenger side of the engine and bolts to a stud on the underside of the passenger engine mount.

To test this theory you can simply unbolt it and check your voltage across the battery terminals with the engine running. If your running voltage goes low again it's definitely an engine ground. Obviously it'll work where it is but runs the risk of being damaged by the engine belt.. Probably best if you unbolt it from there and find a ground stud on the passenger side of the engine or better connect it to the underside of the passenger motor mount if it'll reach. It should if it's that ground. I'll warn you up front it's a bit of a bitch to get to and tighten. #8 in the pic.

If you do change location be sure to recheck running voltage across the battery when you're done. >14 vdc is fine..

If you'd like to get help to ID exactly what that cable is post some more pics showing more of the line and where it runs to.

V/r
John McClain

 

[Markv197]

I’ll post some more pics and then when my wife goes to work I’ll have a look under the car , thankyou for the help !

 

[Markv197]

This is the drivers side , The red marking I’ve drawn is the loose ground wire I found and where I bolted it to, I believe it joins onto the same harness as the drivers side camshaft position sensor , on the other photos with the yellow drawing is what I’ve found with further observation, where I marked in yellow looks like something else is suppose to go there (I’m guessing the ground that I grounded in a different position and marked with red)

 

[Markv197]

I did find this on the passenger side underneath the engine ,I have left this untouched ! I think the wire leads up to bank 1 camshaft position sensor , could this be the reason I’m getting a P0010?

 

[DieHarder]

Looks like it's definitely part of the harness on the driver's side. On my car that line snakes down towards the oil filter and terminates at a connector that plugs into the Oil Pressure Switch (C103) at the back of the oil filter housing. Should be a single GY wire.
Is anything already plugged in there? Are you reading oil pressure with the engine running?

Oil Pressure sensor location: https://iihs.net/fsm/?d=165&f=Oil Filter Adapter.pdf&p=1

Instrument Cluster, Oil Pressure Switch Wiring Diagram: https://iihs.net/fsm/?d=40&f=Instrument Cluster.pdf&p=3

According to an online reference: In a 2008 Ford Mustang GT, the oil pressure switch (or sensor) detects engine oil pressure using a diaphragm that closes/opens electrical contacts, typically acting as a safety interlock for the fuel pump circuit and sending signals to the ECU for the dash gauge/light. It's normally closed: the warning light is on when the car is off, then goes out as pressure builds, and the switch opens; if pressure drops too low, it closes again, cutting fuel to stall the engine, preventing damage.

If it's not the cabling to the Oil Pressure Switch then not sure what it goes to. According to the manual that harness only serves 2 other items in addition to Camshaft Position Sensor 2: 1) Oil Pressure Switch; 2) Dual Pressure Switch - C1078 (Part of the AC circuit).

Let us know what you find.

 

[Markv197]

Never noticed any oil pressure issues from the dash , my brother had a look and thinks them rings are plastic to hold the wires in place …. I found a similar one on the bank 1 side underneath the engine right next to the ac compressor , I feel at a loss right now , could it have something o do with the sjb not having any power whatsoever with fuse 20/21 ?

Photo is of the other ring that my brother said is just to hold the harness in place , but it leads up and connects to the camshaft bank 1 position sensor

 

[DieHarder]

Never noticed any oil pressure issues from the dash , my brother had a look and thinks them rings are plastic to hold the wires in place …. I found a similar one on the bank 1 side underneath the engine right next to the ac compressor , I feel at a loss right now , could it have something o do with the sjb not having any power whatsoever with fuse 20/21 ?

Photo is of the other ring that my brother said is just to hold the harness in place , but it leads up and connects to the camshaft bank 1 position sensor

View attachment 112614

Those plastic rings are there to route/hold the cabling in place. Nothing to worry about other than finding a couple of nuts to keep the cabling in place but not absolutely necessary.

F20 is a fuse in the SJB (Smart Junction Box) that feeds the radio. If it's bad then your radio should'nt work.
F21 is a sort of Interlock that allows the engine to crank only when the Clutch Pedal Position Switch (manual) or Digital Trans Range Sensor (DTR) provide the connectivity needed. If your car starts normally F21 is good.

F20/21: https://iihs.net/fsm/?d=40&f=Power Distribution-SJB.pdf&p=4

The bigger question is to ID that cable to determine if it goes to the Oil Pressure Switch or to something else.

As I said earlier to test if it's a ground or not - disconnect the cable from the stud and start the engine. Read the voltage across the battery terminals. If it's normal it's Not a Ground.

Can you take a pic of the Oil Filter housing? Look for a sensor screwed into the back of it and a line that runs to it. If the sensor is there but no line I'd wager that line you have bolted to the stud on the front of the engine is the Oil Pressure Sensor line.

Here's a drawing showing the cabling for C1367 Camshaft Position Sensor 2; C1078 Dual Pressure Switch; and C103 Oil Pressure Switch. As you can see the harness runs down the driver's side of the engine; splits at C1367. One branch runs over to C1078 and the other to C103 which is the most likely candidate for that line. If it's not C103 not sure what it could be.

Component Location Views - Wiring Diagrams