(E40) Logging sensor: Brake Booster Pressure

[blindsquirrel]

I can't find this sensor in the channels list. It's still active with the DOD disabled, I can read it with a Tech2, it appears in both cyl deactivation data (as both kPa & volts) and general engine data (kPa only). ECM connector C3 pins 6/15/36; this is a separate sensor in the booster, not a derived value from the MAP sensor. HOW I MAKE WORK PLZ?

screenshot.01-04-2019 15.39.25.png

sensor unplugged:
screenshot.01-04-2019 15.38.41.png

[blindsquirrel]

I have re-polled for supported parameters, then filtered for 'brake', 'booster', 'pressure', 'vacuum'. Not in the list. I don't want to open a ticket and waste support's time if the problem is something I'm not doing right.

[blindsquirrel]

I guess I should have titled this "How to view PID that isn't in the list" or something, there's no FAQ or guide that covers how or when to open a support ticket, or what you can ask for, or anything about how the process works...

[blindsquirrel]

No one has ever had a sensor that VCM Scanner couldn't find? Really? I'm the first this has happened to?

[5ft24]

The TECH2 probably gets that data from the ABS computer, not the ECU

[blindsquirrel]

Nope, that sensor is only used for the AFM/DOD stuff, it's not brake related (booster vacuum is monitored while DOD is active, if vacuum necessary to allow safe braking falls too low V4 mode is deactivated until vacuum builds to a safe level again). Vehicles without AFM/DOD regardless of platform don't have the sensor present, and the ABS systems of same platform vehicles with and without AFM are identical.

I have a support ticket open, they are investigating. If they add it, I believe it will enable those pins for external sensor use on ANY E40, just add pins to the connectors and off you go.

[blindsquirrel]

'Ignition Controls - Sensors and DOD Controls' 2006 Envoy LH6
booster vacuum sensor.png

Displacement on Demand (DoD) Inhibit Reasons

Listed below are the powertrain conditions that will inhibit V4 mode, while operating under light load driving conditions:
? Engine manifold vacuum low
? Brake booster vacuum pressure low
? Accelerator pedal position rate of increase too high, electronic throttle control
? Accelerator pedal position too high, electronic throttle control
[and so on, loong list]

? Fault Active or Fault Pending--displacement on demand (DoD) is disabled for the following faults:
- Manifold Absolute Pressure Sensor
- Brake Booster Vacuum Sensor
- Engine Oil Pressure Sensor
- Engine Coolant Temperature Sensor
- Vehicle Speed Sensor
- Crankshaft Position Sensor
- Engine Misfire Detected
- Displacement On Demand Solenoid Driver Circuit

[5ft24]

Ah...