99 E300 TD cuts out Ph 5 <=== M.B. DOC pls. - PeachParts Mercedes-Benz Forum

TMAllison · #1 03-29-2004, 11:01 PM

Continuing woe's from four prior posts last 5 or 6 weeks.

Got car back from local dealer 7 days ago and have put 750 uneventful quite enjoyable miles on car; my first since purchasing two months ago.

I like. Alot!!!

Today got MIL. Fluids, belt, temp etc. fine. After checking, on second start had glow plug indicator light stay on maybe 5 seconds then went out.

The MIL code is "P0380 Glow Plug: Heater circuit Malfunction".

No apparent fuel leak at fuel thermostat or fuel line or elsewhere on or around IP; I've cleaned everything up to extent I am virtually certain of this.

Question: Recent work by Indie, Me & Dealer (750 miles ago) included replacing glow plugs, all fuel lines; fuel filter, pre-filter and o ring; fuel relay module, fuel shutoff solenoid (P0215 & P0180) AND finally engine wiring harness and a few other lessor items). Is it possible P0380 comes from a bad electrical connection to one of the glow plugs from when the harness was replaced? They seem to be clipped in place but is hard to see (STUPID MANIFOLD!!!

).

Any harm in driving 3 cycles to see if MIL will go out?

Dealer recommended replacing oil sender unit in future because of minor leak and trans shifter bushings. Everything else looked good.

As always, thoughts greatly appreciated.

mbdoc · #2 03-30-2004, 08:12 AM

P0 380 has nothing to do with previous work.

P0 380 means that the glow system relay (computer) reported a fault, most likely a bad control relay. Very easy to test!
The glow relay MB number 022-545-75-32 lists for $83.

jcyuhn · #3 03-30-2004, 09:50 AM

My '98 E300 reported this fault every time the glow plugs were replaced. We put in the third relay at six years of age, about 55K miles. They seem to be a bit of a maintenance item

- JimY

TMAllison · #4 03-30-2004, 11:11 AM

Thanks both.

The whole car seems to have been a bit of a "maintainence item" recently....but, think I will keep it.

TMAllison · #5 03-31-2004, 11:52 AM

Tuesday evening (apparently after the 3rd warm up cycle since light came on Monday afternoon) the MIL turned itself off.

So fault appears to have been a one time event.

In hindsight, while registering car on Monday, the DMV inspection agent turned on ignition and I am thinking that when I hopped back in car and turned key it was already at position 2 and was auto-started with cold glow plugs?

#6 08-09-2004, 01:56 PM

M.B. Doc - how would one test for this bad glow system relay? Thanks, Paul

mbdoc · #7 08-09-2004, 06:01 PM

That code comes only from defective glow plugs (excessive draw) or relay. If testing the plugs comes out correctly, one can only assume that the relay is the problem.