A few issues; which order to tackle them?

[chitown60608]

I've got a laundry list of codes that I need to take care of. I'm looking for advice in which order to repair them.

2010 X5 3.0d M57N2
105k miles

These are the codes:

DME/DDE [D62M57A0] | 43E2: Throttle-valve actuator, activation
DME/DDE [D62M57A0] | 452A: Info - particulate-filter system
DME/DDE [D62M57A0] | 4212: Glow plug, cylinder 1, activation
DME/DDE [D62M57A0] | 4222: Glow plug, cylinder 2, activation
DME/DDE [D62M57A0] | 4232: Glow plug, cylinder 3, activation
DME/DDE [D62M57A0] | 4242: Glow plug, cylinder 4, activation
DME/DDE [D62M57A0] | 4252: Glow plug, cylinder 5, activation
DME/DDE [D62M57A0] | 4262: Glow plug, cylinder 6, activation
DME/DDE [D62M57A0] | 480A: Particulate-filter system
DME/DDE [D62M57A0] | 481A: Particulate-filter system
DME/DDE [D62M57A0] | 4D00: Exhaust backpressure sensor
DME/DDE [D62M57A0] | 4010: Exhaust backpressure sensor before particulate filter, signal
DME/DDE [D62M57A0] | 4CF3: Exhaust backpressure sensor, signal

Idle exhaust back pressure is steadily 16.3psi (1124 mbar). On a little 30 minute drive through town today, never getting over 40mph, it got as high as 29.04 psi (2002 mbar). Coolant temp never exceeded 58C.

In my mind, the thermostat has gone bad. With the thermostat dead, it killed the glow plugs and gp control module pretty quickly since they probably rarely turned off. And those failing led to the DPF being clogged as it would prevent a regen.

So, my plan is to replace the thermostat and water pump. Then replace the glow plugs and gp module. Should I probably just count on the throttle body being toast and filled with oil as well and replace it at the same time?

If I'm off here, please let me know what you think it would be or how you would tackle what's going on.

[wcs531]

When you say you're looking for the right order to do them in, is it just too much time or money to do all at once? You will certainly have a few other maintenance items on the horizon as well, but seems like youre on the right track. Not sure on the throttle valve. Coolant temp is way too low as you suggested, so do thermostat asap and might as well do water pump while you're there.

Glow plug module failure is common, I would think its that before all your glow plugs going at once. Dont think a bad thermostat would cause glow plug issues, but I could be wrong. I thought they were just for starting and initial warm up. With that said might as well do the plugs when the intake manifold is off, but if youre really trying to get by with the bare minimum they could be ok still at 100k.

Other things I'd consider replacing if you'd prefer to get it all out of the way with:
Harmonic Balancer (and possibly clutched alternator pulley)
Coolant flange near the glow plug module
vacuum lines
pressure converters
Valve cover gasket usually gets cooked around 100k, which is a decent sized job.
Belts/pulleys (I forget if the egr needs to be off for these, will likely be easier to do when doing thermostat)