2004 diesel 2.0D glow plug coil light
 

Hi everyone I have a question, about glow plugs and the indicator light. So I have a starting problem with my bought volvo s40 2.0D 2004.5. And I am trying to figure out the missing pieces who is to blame:
1. Throttle body flap,
2. Glow plugs,
3. Not enough starting current.
1. Throttle body was cleaned with a carb cleaner and look pretty clean. EGR is blanked so no air comes from exhaust. Doesn't look like the throttle body cleaning helped.
2. Mechanic checked the glow plugs continuity and said they don't need changing. But what bothers me that the coil light on a dashboard only blinks and goes off when the ignition key is turned, no matter the outside temperature -6C or +10C. What is your experience with the coil light on the dashboard should it stay ON maybe even for a bit longer? Is there a way to check if the glow plugs are really turned on when the ignition key is turned (without taking them out)?
3. Fact or coincidence that if I turn off the lights and all electronics it takes less cranks for the engine to fire it up.

Sorry for the long post, the winter is coming.. So I would like to sort the problem till then.

I think you have answered your own post here!

If I turn off the lights etc. I would point the finger of blame at the battery. How old is it, how often do you start and drive the car a reasonable distance?

On my 2005 2.0d V50 I put the key in and turn and it usually fires. I have had this year, a new alternator and battery as well as wishbones and shock absorbers.

Get the battery and the charging circuit checked out.

Battery I think is made in 2011 and also mechanic said that the alternator isn't volvos stock so at some point it was changed. Looking at the voltage when the car is stopped or running looks like they are okey. Today it took quite some offer to make the car running even anti-skid error popped on the screen. But there is no problem starting the car when the engine is warm

When I had my alternator changed in April was told that I would probably have to change the battery within a few months.

Sure enough, in September the battery low voltage or similar message came up on the dash and had to get another battery. The new alternator had literally cooked the original battery. My car is 2005 registered so almost 9 years was pretty good.

I would get your battery checked seeing as the alternator has been changed.

What does ok mean?
What were the figures?
What's the battery voltage during cranking? This is the key to knowing whether a new battery is required.

Are you sure you throttle body is not damaged? it is not unheard of that people have damaged the throttle body so that it become slightly misshapen more so down to position than anything else?

Additionally as said what rating is on the alternator? (it was known for some time the earlier cars failed because the alternator was a lower rated one than the later cars (if you get a bigger more powerful variant then you need a software update). Battery is another potential issue.

Glow plugs on the 2.0D are not used until -10.

Okey new battery Varta 85mh 800A! Problems almost solved starts much better. But still looks like it has a sluggish start I mean RPM builds up some times pretty slow and sometimes jumps fast then starting the car. On this weekend I think I will try to disassemble the throttle body and take a closer look maybe try some sanding paper for the edges, because it looks like that if you use some force to close the flap it gets a bit stuck and you need to push it again to open it.

The volvo fix to avoid that is to chamfer the edges :). It should cure the slow start.