Confused with Manifold Differential Pressure Sensor Code

[Seven Zs]

Hi -

First post, but have been searching deep in the forums for a while now as I go through my new to me 2007 Z4 3.0i with 75k miles.

I continue to get a P1105 code, which isn't heavily discussed on this forum or others. From what I read and from the local indy's suggestion, its the Manifold Differential Pressure Sensor. Short story is, I've replaced it (twice) and still getting the code. No other codes. Here's what I know:

No real symptoms, car runs and drives great - idle wasn't smooth when I got it, but with what I've done it's smooth now. I've done the plastic valve cover (which includes PCV on this engine, no separate CCV), plugs/coils, intake manifold clean and gaskets, throttle body clean and gasket, new breather hose, new air filter, etc.

When I had the old plugs out, they all looked evenly worn and not sooty. Intake valves looked shiny when I had the intake manifold off.

I find that after I clear the code, drive the car, then turn the car off and restart it, that's when the code appears.

Only other potential oddity I noticed was when I remove the oil filler cap, there's some vapor that cycles in the valve cover when running and some escapes when the vehicle is off and I remove the cap. No air comes out, just very slight vacuum. I've owned many many cars, and never recall removing the cap while running so I'm not sure if that's any indicator. I did however smell the vapor and the inside of the valve cover and the oil has an exhaust smell to it...fresh oil change too.

I'm stuck...

Thanks for any input.

[Steeler]

Hello,

I answered your thread on the other forum as well.

Apologies if this seems obvious.
A search on REALOEM for part # 13628657300 Pressure Differential Sensor.

https://www.ecstuning.com/b-genuine-...628657300~oeb/

Returns this result.

https://www.realoem.com/bmw/enUS/sho...56#13628657300

Not one to throw parts at a car to chase codes but the code is pointing directly to this sensor. It's easy to access and relatively cheap. May be worth a try.

Originally Posted by Seven Zs

Hi -

First post, but have been searching deep in the forums for a while now as I go through my new to me 2007 Z4 3.0i with 75k miles.

I continue to get a P1105 code, which isn't heavily discussed on this forum or others. From what I read and from the local indy's suggestion, its the Manifold Differential Pressure Sensor. Short story is, I've replaced it (twice) and still getting the code. No other codes. Here's what I know:

No real symptoms, car runs and drives great - idle wasn't smooth when I got it, but with what I've done it's smooth now. I've done the plastic valve cover (which includes PCV on this engine, no separate CCV), plugs/coils, intake manifold clean and gaskets, throttle body clean and gasket, new breather hose, new air filter, etc.

When I had the old plugs out, they all looked evenly worn and not sooty. Intake valves looked shiny when I had the intake manifold off.

I find that after I clear the code, drive the car, then turn the car off and restart it, that's when the code appears.

Only other potential oddity I noticed was when I remove the oil filler cap, there's some vapor that cycles in the valve cover when running and some escapes when the vehicle is off and I remove the cap. No air comes out, just very slight vacuum. I've owned many many cars, and never recall removing the cap while running so I'm not sure if that's any indicator. I did however smell the vapor and the inside of the valve cover and the oil has an exhaust smell to it...fresh oil change too.

I'm stuck...

Thanks for any input.

[Seven Zs]

Thank you. I did replace that part as the first response to the code reappearing, and still getting it. I took it to the local indy euro shop today and they suspect that it's an unmetered air leak. They smoke tested it and said the intake boots are misshaped and not sealing well from years of tightening/loosening. We'll replace those and see if that does the trick, otherwise they'll continue to diagnose other systems. They did also notice a previous owner installed a Dinan throttle body (I'm still learning this car and realized that's an "upgrade" to OEM) and will be calling their Dinan rep to see if they need to check ECU settings.

[Seven Zs]

Still chasing this issue with one development. The new intake boots seemed to do the trick for about two weeks, then the code started reappearing again.

I checked voltage on the wiring and tested resistance. Not a wiring or harness issue.

Here's the one thing that's interesting...when I had the throttle body off, I noticed the plastic mating surface of the intake manifold had a small "warped" area to it. I readjusted the TB to more centered and tightened it down. Cleared the codes and ran several off/on cycles. The light isn't coming back on, but the ECM does show the code as pending.

Any experience with "smoothing" the plastic mating surface to eliminate any air leaks not addressed by the rubber washer? Or, is this just wishful thinking that it's my issue?

[Seven Zs]

Think this one is solved. Replaced the Dinan TB with an OE one and sanded the plastic mating surface smooth on the intake manifold. Torqued to 9 nm.

So far, no trouble codes or pending codes. Before, it would show a pending code P1105/2d29 immediately after startup and light the SES light on the next startup. Hope this one is done.