Would VIDA show fault with glow plug?
 

C30 1.6D 2009

Reduced Engine Performance issue.

Vida says - ECM 6620 Glow relay control - faulty signal

Im thinking of first changing the glow plugs to see if that sorts it, because easier/cheaper.

Just wondering if Vida would show a fault if specifically with one of the glow plugs? If it would then I guess not much point in replacing them.

Thanks

The glow plugs should only be used for cold starting, not for running. As such if you have a performance problem, there's something else not right somewhere.

Do you have a cold start problem? If so, investigate the glow plugs individually but double-check what voltage they operate on, for some strange reason cars after 2000 (in general) have some strange voltage glow plugs so don't use full battery voltage until you know they can take it.

First port of call with any fault is to read the codes (which you've done), clear them and then drive it and check the codes again. You can never know if it's a historical code that has suddenly caused you a problem.

Thanks Dave,

I tried clearing the codes and going for a drive. The only code to persist was this EMC 6620 Glow relay module - faulty signal.

I recently learnt that the glow plugs are activated by opening of the drivers door to pre heat the engine. Looking at the hidden menu on the dash I have DDM DTC SET (Driver Door Module), and was wondering if this could be link. This has been on their many months now, I thought it was related to driver door airbag or something.

The reduced engine performance msg does come up when I start the engine, or when I turn the key to position ll, but not sure if that is coming up because I haven't cleared it yet from the first time it popped up, which was driving a little aggressively around a roundabout.

I don't know or use VIDA but at an edumacated guess i'd say DDM DTC SET translates as :

DDM = Drivers Door Module (as you've already said)
DTC = Diagnostic Trouble Code
SET = Set - status report so there's a DTC with information on a problem with the DDM

With that in mind, do you have any problems with cold starting?

Also does the courtesy light work when the door is opened? If not, i'd have a look at that, might be a blown bulb, switched off at the light or the door pin switch or wherever the switch is on yours (possibly in the handle to trigger the courtesy light and glow plug relay at the time you lift the handle) and check that all works. Sometimes the ECUs depend on the bulb working as a pull-up resistor to the ECU and when the bulb is turned on by the door pin switch or similar going to earth, it pulls the ECU input low triggering the timing circuitry.

Not sure if that will apply to yours but many others work that way, reasonable to assume that as a good starting point, even if it's wrong you may uncover the problem anyway by investigating that.
Don't forget to clear the DTCs (codes) before testing each time or you won't know if you've found the fault.

That fault code indicates there is something wrong in the main power supply to the glow plugs or the current is not as expected , either shorted glow plugs or open circuit glow plugs or wiring ... Possibly a glow plug but prove it first by measuring their resistance to ground with the leads off ... they should be very low about 2 ohms or so ... and all the same reading .. Only the larger volvo engines have individual fault diagnosis for each glow plug .

No problem cold starting, to be fair its starts up on the button every time. Any conditions.

Is it in the door handle that triggers the glow plugs to fire up? I wonder if they (or not all) the glow plugs have been warming the engine as should.

Also, no issues with nterior lights. Lights come one when exiting the car and Im sure they come one when I remote unlock when getting in.

NO the ignition isnt on until you turn the key ..

The Design and Function section of Vida should explain glow plug control and I doubt the drivers door will feature but I stand to be corrected.

Click on the fault code in Vida then View Information for an explanation of the fault code and the possible causes and fixes and work through them.

As said, a resistance test of the glow still in place should be all that's required to diagnose or eliminate them.

Hi Clan,

You helped me previously with my accelerator pedal sensor, which turned out to be a simple clean of the CEM board/connectors with contact cleaner. No issues since.

Hoping this is something as easy to fix with contact cleaner again lol. I searched for ECM location and saw in a post from 2016 you said it was located on the right behind the front wheel arch... is that right looking at the front from outside (passenger side), or right from within the vehicle (drivers side)? Just incase I do need to get at the glow relay and get the contact cleaner out.

Im not too clued up when it comes to electrics, have had a go before with varying success. Like the accelerator pedal great success, thanks. But if I am going to test the glow plugs; "by measuring their resistance to ground with the leads off".... am I right in understanding that you mean remove the leads from the plugs first, then test the resistance to ground by holding one tester probe (+ red) on the glow plug and the other probe (- black) on e.g. vehicle body, or anywhere that would be ground/earth?

If they are higher than 2 ohms they need replacing?

Thanks

@2:00 https://youtu.be/lsuP1QkKcXU