2.4D (2005 on) DTCs set BCM ECM SRS no swirl arm 58 P3 V70 2.4D Auto Estate

[Vman01]

163bhp 120k

Can anyone help please (other than Simmy who has already kindly been in touch).

Similar posted in V70 forum but below are queries specific to the engine across other models so hopefully more eyes will see this.

No EML/CEL (did have 097 with service message code but sorted at oil change, still have intermittent 021 message code when clearing messages - is this the DPF?)

[READ+2xrear fog light] gives DTCs set: BCM ECM SRS

Swirl arm is present on the PWM stepper motor but not connected to swirl flaps link. Arm is front side of air ducting so won't rotate back on, it didn't fall there so looks like it could be delibrate (hence my concern about reconnecting) or perhaps the ducting has just been refitted after it disconnected?

Looking for help on the following related questions please, many thanks in advance.

- If swirl arm is not connected will it throw ECM DTCs? are BCM and SRS unrelated?

- *Will the car refuse to do a regen if any DTCs present?* (or only if ECM DTCs are present?) *This is my urgent concern*
Could this explain the intermittent 021 code? (a borderline blocked DPF?)

- Could there be a reason why the arm is not connected or a risk to reconnecting it without further investigation (I read somewhere that one car wouldn't start after reconnnection though understand from one reply that it should be fine?). Swirl flap level has full manual range of motion by the way, so no obvious obstruction.

Many thanks in advance.

[passenger]

Is funny. Last year detached link: error in VIDA appeared. I attached it, cleared codes.
Now it's again detached and no errors. Probably when stayed closed, there is no errors.

I was driving through mountain pass with detached link but stayed open and I had like 100 Nm less. I stopped, closed flaps with hand and had all 400 Nm back

[Vman01]

Originally Posted by passenger

Is funny. Last year detached link: error in VIDA appeared. I attached it, cleared codes.
Now it's again detached and no errors. Probably when stayed closed, there is no errors.

I was driving through mountain pass with detached link but stayed open and I had like 100 Nm less. I stopped, closed flaps with hand and had all 400 Nm back

Hmm. It would be interesting and helpful to know what goes on behind the scenes.

From this 'NewCarFeatures2006.pdf' I found https://www.volvoclub.org.uk/tech/Ne...006-Theory.pdf

"The throttles are closed during idling and then open steplessly up to an engine speed of approx. 3000 rpm. At
an engine speed above 3000 rpm the throttles are always open. They also open if the load is high despite the
engine speed falling below 3000 rpm.
The position of the throttles is determined by the ECM based primarily on load and engine speed."

also

"By means of the feedback the ECM can determine if the actual position of the throttles corresponds to the
required position. If this not the case then a diagnostic trouble code (DTC) is generated."

The same document states that the throttles (swirl flaps) position is assumed through the linkage to the motor arm position with a Hall (magnetic) sensor. So perhaps it depends on the feedback from the electric motor position sensor as to whether a code is produced? If resistance pushes the arm off and also the motor off its expected position then a code will be produced. If it happens again without a code then perhaps the arm came off without the motor being out of position (as the arm connection is now loose and so no longer interferes as much?).

It offers others insights, perhaps worth someone adding it to a sub-forum sticky with similar documents?

[passenger]

You see, I was sure it's opposite : in idle is open and on throttle is closed (to build more pressure when closed)

[Vman01]

I think it's just all about emissions. Minimise at all states but accept it's necessary to increase air flow and sacrifice burn efficiency for high loading.

[Vman01]

Happy to report that all codes cleared (thanks to Simmy - a gentleman and a scholar) and maintained a clean bill of health after a good long drive. I've left the swirl throttle actuator arm off for now with no codes generated (so far as I didn't push it hard), so that answers some queries I and other have had about that.

No sign of a regen yet, so maybe not ready for one or I just did not notice.

By the way I didn't mention the PBM DTC also reset itself over time as well, so some DTCs can reset automatically without (apparent corrective) action. The codes were there when I picked up the car so have no idea when or why they appeared - perhaps some due to flat battery/disconnection?

Now looking into obtaining VIDA-DiCE and getting my teeth into that!

[Simmy]

if the dpf is working well. its almost impossible to tell when its doing a regen other than mpg may drop a little. . it was great to meet at weekend . good news that non of the codes have returned after a good run . keep in touch with any up dates or problems.

[Vman01]

Originally Posted by Simmy

if the dpf is working well. its almost impossible to tell when its doing a regen other than mpg may drop a little. . it was great to meet at weekend . good news that non of the codes have returned after a good run . keep in touch with any up dates or problems.

Will do, cheers.