2007 Mini Cooper S, 108k, AEM Intake and aftermarket vent to atmosphere blow-off valve with pneumatic solenoid

Codes:
P0100 Mass Airflow Sensor Circuit Continuity Monitoring
P113B
P0010 A Camshaft Position Actuator Control Circuit
P0444 Evaporative Purge Control Valve Circuit Open
P2088 A Camshaft Position Actuator Control Valve Low
P0458 Evaporative Purge Control Valve Circuit Low

Of these, P0100 and P113B come on as pending with ECU cleared of codes / ignition on. Start engine and the other four are flagged quickly.

Car shows low power (half) CEL. Drives normally but no power.

Car was previously fine. Drove on a short errand and on the drive home, CEL illuminates and no power (won't build boost).

 

This is what these codes seem to have in common

 

Pin 41 at ECU connector I get ~4.9-5V when back probing but at the MAF, for instance, I get 3.5V.

 

Initially suspected bad MAF was causing the other codes but swapping a new MAF yields no change and is what lead me to "what do these things have in common".

 

If I unplug the solenoid for the blow-off valve and then it's 0V at the other 4 points...

 

I'd try physically removing the BOV solenoid and returning that part of the plumbing back to OEM conditions. A broken / leaky BOV actuator can cause all kinds of grief.

 

MAF and camshaft faults are almost always timing. When we see those faults together thats usually where to start.
But i have heard of people getting faults with aftermarket BOV. May wanna take a peek at that, Regardless I suggest checking timing

 

Incorrect data here. Looks like my multimeter was misbehaving. Voltage was consistent 3.5V at all points when using a proper (Fluke) multimeter. Well, it was 5V at the ECU, then 3.5V at the ECU. ECU apparently can't make it's mind up.

Looking at the diagram and thinking further about the problem at large, solenoids (BOV, WG, purge, VANOS) would normally operate at 12V, no?

 

My measurements were limited to MAP sensors, but I expect anything driven by the ECU will be limited to 5VDC max, with 3.5VDC being typical. Variations between 3.5 and 5 depend on load --- whether or not the circuit being measured is in use.

 

Well, the same pin also showed 12V at some point during testing, slightly inaccurate voltmeter may have been less of a culprit and an inconsistent ECU more of a culprit.

Three different voltages measured with the key in accessory and no other change at the same location?

Voltage can't vary at this pin to 5 different devices. That makes no sense and seems to violate basic principles of electronics. It is a parallel circuit. Voltage coming out of the pin should be equal at all 5 points. All 5 points have continuity with each other with little resistance/difference in resistance.

I don't understand BMW/Mini service manuals/procedures. I'm not a BMW/Mini trained tech but I've been servicing my own cars using factory (Mazda) manuals for a long time. They (Mazda) list the nominal output voltages and resistances for almost all of the ECU controls and many other parts of the vehicle. They still seem to list them for OBD-II cars in newer factory manuals.

 

Apparently, I have the Forge Blow-off valve kit:
https://www.forgemotorsport.com/Blow...uct--1026.html

 

This seems to be the solenoid.

Nominal voltage: 12V

So, the ECU output transistor/voltage regulator/device has malfunctioned...

 

Problem has been resolved. It has been verified as an ECU/ECM failure. That pin should have 12V. It doesn't.

 

This is X60231 and where 12V is distributed to the five components:

 

I have the same codes, did you end up swapping the ECU and the issue was solved?

 

You need someone trained in automotive electronic diagnostics to do the diagnosis on your vehicle to determine what to do next. It’s not our day to day as a car audio shop but I was eventually able to isolate it and make “non-Mini approved repairs” to solve the problem...

It could be a bad ECU output but it could also be a short or an open circuit on that pin. ECU repair was $500-ish at the time I posted this.

You can point your technician to this thread to reduce some research time and it is possible the 12V output is not working on that circuit...BUT...it could be a short or open and another ECU may not solve the problem or it could be damaged if plugged into your car.

You have to get ECU/CAS/keys as a group if you want to swap secondhand parts with no coding, if I recall correctly. Not exactly plug and play...

Repair to that circuit fixed the check engine codes in my case but then one right after another, was electronic throttle body failure, coils went bad and it’s on it’s 3rd HPFP (second one was the cheap $150-200 non-OEM which worked for a while and then same symptoms returned, so I bought the ~$450 Valeo) and all these failures were within a
span of a few hundred miles.

As fun as the car is, it will probably be the first to go if I have to cull the herd.

 

Interesting, I will try and test that connection to see if I get 12v at the split.

 

3v before the split

The split

 

What repair to the circuit have you done?

 

So I got a used ecu, key, key module and other computer from a different mini. Although it didn't start my car, the voltage was still around 3v with used ecu, ignition on. I'm in a pickle.