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What is MECU Supply Voltage?

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DanT
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Year and Model: 2008 XC90 4.4L
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Post by DanT »

Hello,

I'm trying to troubleshoot some codes on my 2008 XC90 using VIDA and i noticed a field, MECU Supply Voltage in the freeze frame data.
Does anyone know what this voltage is?

On the DEM and SAS modules the voltage is around 11.5V but on the BCM its ~28V. (anything over 15v on a car peaks my interest)
BCM-C00201C ABS Pump Motor Control.png
Checked the usual places but couldn't find what this voltage is referring to in VIDA.

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abscate
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Post by abscate »

Supply voltage to the CEM, and 27 volts is way too high. Something is up.
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volvolugnut
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Post by volvolugnut »

At first I thought you had a hybrid model. That high a voltage does not sound good. Is it steady voltage?
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DanT
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Post by DanT »

Following up on this, in hindsight would probably have made more sense to post the codes the freeze frame data is from.

I have a failed SAS unit at the moment and the freeze fame data is from the BCM complaining.
BCM-U042864 Invalid Data Received From Steering Angle Sensor Module - Algorithm Based Failures - Signal plausibility failure
BCM-C110787 Communication between control units - Bus Signal / Message Failures - Missing message

@abscate Thanks for the info this may make sense with the accompanying fault codes

@volvolugnut Unfortunately I can't find a parameter to monitor the MECU or CEM supply, I've only see it in Freeze Frame Data
Other modules report the MECU voltage in "normal" ranges in the frozen data of fault codes

If its the CEM voltage I feel pretty safe its a weird communication issue around the SAS/BCM as all the other modules report fine.

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