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Discussion Starter · #1 · (Edited)
I have a 2003 Freelander SE (2.5L) KV6 engine, and have recently experienced misfire issues, symptoms include loss of power, and stuttering of the engine at varying RPMs. the error codes I pulled are:
P1475 - Variable inlet manifold motor 1.Short circuit to ground
P1471 - Variable inlet manifold motor 1.Short circuit to V Battle inlet manifold motor 1.Short circuit to ground
P1472 - Variable inlet manifold motor 2.Short circuit to ground
P0303 - Cylinder 3 Misfire Detected

What I did:
I did some research, and decided to start with troubleshooting items related to cylinder 3, sparkplug and coil (thinking: if the upper intake manifold was bad, more cylinders would be impacted or would have seen random misfire code). I found the spark plug 3 was too loose, and the plug seemed to have a coating of oil on it, not dripping but had a sheen and possibly pre-ignition glazing. I replaced the plug and that seemed to help but the same codes surfaced after a short test drive.
91665



Next steps:
I'll replace the coil for cylinder 3. if that doesn't work, I'll check the VIS (Variable Intake System) motor, that's attached to the left side of the upper intake manifold (as specified in the error codes above) which may need to be cleaned, rebuilt or replaced (maybe the upper intake manifold too).

Helpful links:
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6) OBD-II Diagnostic Trouble Code (DTC) Definitions, Categories, Faulty System and Components
7) Inlet Manifold Engine Ticking Rattle V6 Freelander

I'll post follow-ups on troubleshooting and solutions.

>> Solution >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
A) the three codes related to the VIS issue (P1475, P1472, P1471) required both VIS motors to be changed (they operate the two intake baffles) AND
B) the misfire in cylinder 3 (P0303) was ultimately fixed by replacing the ignition coil. I did change the spark plug a couple weeks earlier, but that wasn't a fix.

The order I made the fixes helped me pinpoint the issues:
1) changed sparkplug in cylinder 3 (didn't change error codes)
2) changed VIS motor 2 (fixed error codes P1475 & P1472)
3) changed ignition coil (fixed error code 0303)
4) changed VIS motor 1 (fixed error code P1471)

everything works now, no errors and best of all the power band is restored!

* I purchased a used upper intake manifold with both VIS motors for $200 + $30 shipping it was in good shape from a donor without errors. I decided to replace the VIS motors instead of swapping out the entire manifold, the manifold baffles weren't broken, they were just a little sticky and needed to be moved back and forth (I was seeing results and stayed the course). I'm keeping the extra manifold body for spare parts.

I'm looking forward to putting in time on a 2010 Range Rover HSE Supercharged; It'll be a lot more rewarding after these maintenance intervals :)

*2/6/2020 Note:
I'm hoping these additional notes will be helpful. I've been reflecting on why/how the two VIS motors would have died around the same - when these cars sit for prolonged periods of time, I believe the baffles don't get enough movement and get a little sticky, and if there's a cold snap the baffles are sticky and frozen; the tiny electric VIS motors burnout from the load of trying to articulate baffles that are pretty much stuck. When I received the replacement intake (used) there was a significant amount of lubrication fluid visible when removing the VIS motors (to replace mine that don't work), now I know why :)

Get a scanner and check it frequently, not all engine errors trigger the "Service Engine Soon" lamp, you might notice a drop in performance or something that doesn't seem right, having an ODB/2 tool will help you make sense of what's going on. you don't have to buy the expensive scanners, something like INNOVA 3020d from Auto Zone (like $60), was a great start for me.
 
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