Renovelo Forum

Hey guys, bit of an obscure one. Lots of MS45.1 cars are prone to a P2227 or barometric pressure sensor error. This sensor is built into the DME itself and replacing it requires opening up the DME and doing some soldering, which is always fun. The thing is... nobody can tell what on earth that sensor is for, what range the car is expecting, etc.

Anybody here know what tables that sensor may pertain to, or if there's a way to just... disable the MIL or tune out the sensor entirely by zeroing the pertinent table? My car will throw it like clockwork if I set my cruise on the highway for 30+ miles when it's warm out. Good working OEM MAF, no vacuum leaks whatsoever. Just curious if tuning could be a workaround, or any information, really.

The ECU references this sensor to determine altitude and ambient air pressure. It has compensation tables built in to adjust fueling based on its readings. It is likely possible to tune it out. The only broken sensor I have seen was on MSV70, and the logic is a bit different on that ECU.

We can clone your current ECU or try to remove the error remotely, but we are a business so it wouldn't be free. If this happened on my personal car, I would clone the ECU instead of attempting to remove the error.

Additionally, the maximum diagnostic value is 4.75V and minimum is 0.25V.

Hi

How does the DME (ECU) use the Baro signal?

If I vacuum bag the DME and alter the Baro value by applying vacuum or pressure, I'm seeing:

• The MAF value increased for a lower Baro
  The MAF value reduced for an increased Baro.

Is this correct?

It seems opposite to what you would expect to see? Maybe it's because the ambient temp is not changing?

The fuel trims and Pre-cat O2's react as one would expect for an over reporting MAF = Rich fuel trims