Hi all, i get the glow plug light coming on when starting the van.multiecuscan shows error p0380 -11 short circuit to ground.this is with the glow plugs disconnected.if i remove the relay it shows error p0380-13 open circuit. checked the wiring from glow plug relay socket to plug at front of engine . no contact to either earth or battery. is it possible the glow plug control module is faulty?
i want to try an eliminate everything before forking out for a new glow plug module.
the plugs are all reading 1.2ohm
any suggestions please
thanks
Lindsay

Hi 47643

The glow plug "relay" M015 takes a high current feed from Fuse F01 (50A) in the under-bonnet fuse box. This goes via a set of high current relay contacts to the four glow plugs. The relay coil is driven by an electronic circuit which has a low power feed from Fuse F11 (15A), an Earth connection and a Logic input from Pin 93 of the Engine Management M010 which goes low to tell the glow Plugs to switch on. The relay will click audibly when it turns on.


In addition, there is an inbuilt diagnostics electronic circuit which checks all 4 glow plug currents. If anything is deemed to be outside the acceptable range, the diagnostic output on Pin 9 will go high. This feeds Pin 52 of the Engine Management M010. Clearly, if any or all of the glow plugs are deliberately disconnected it will flag up a fault and you will get an error code logged and possibly also the glow plug light will flash for a period.

Similarly, if you take the relay out, the ECU will sense that the fault feedback line is out of range and this too will log a fault.

You should see continuity from four of the connectors on the relay socket to the four glow plug connectors on the plugs themselves:

Plug 1 (UK driver's side of engine) Brown wire. Pin 1 of Relay
Plug 2 Red wire Pin 2 of Relay
Plug 3 Yellow Wire Pin 3 of Relay
Plug 4 (Air Filter side of engine) Green Wire Pin 4 of Relay

If things are working properly, you should see about 1 volt less than battery voltage on each glow plug. They each draw something like 15 Amps to begin with, which drops after a few seconds as they heat up.

Your cold readings on the plugs of 1.2 ohms sound right to me. Unfortunately, it is possible for plugs to go faulty only when hot (as I know to my cost), so the light coming on and the error code may simply be reporting a genuine fault. The next step might be to get a specialist tester to check each glow plug under realistic conditions, i.e. with 11 volts applied.

hi , thanks for the info, i am testing with ignition on , but engine not running
same fault , does not make any difference if glow plugs connected, still s/c to earth.it looks like it is pointing to the relay module. forgot to add

it is a 2.3 130hp euro5+ van 2015

Hi again

It would be great if fault codes said something like "Component XYZ has failed and you need to replace it". Unfortunately, built in diagnostics have yet to reach that level of sophistication. If the engine ECU sees an unexpected level on the fault feedback line from the Glow Plug Controller (Relay), it doesn't "know" if its a genuine glow plug fault, a faulty controller or a fault in the feedback line wiring e.g. a short to ground pulling it low. So the fault details listed by Multiecuscan etc cannot be taken too literally.


In order of most to least likely, I would say 1.) Glow Plug 2.) Glow Plug Controller 3.) Wiring Fault

The reason I say this is strongly influenced by my experience last year, when I spent weeks chasing a similar fault. All the wiring was checked and double checked, I tried a new controller which made no difference and I checked the cold resistance of the Glow Plugs with an ohmmeter and they all read 1.0 ohms. It was only when I did a test on each plug with an 11V high current capable power supply that I found No 4 plug was going very low resistance when hot. Presumably something expands inside and touches the casing.

A new controller isn't wickedly expensive, and I get the impression you don't need to pay garage labour rates to swap it out. So maybe worth a try, but be prepared for disappointment - sorry !

hi, what is puzzling me is it says s/c to earth with the glow plugs disconnected?.

update, did more testing today. it is looking like a glow plug fault. waiting on mechanic to prove. i do not want the risk of removing glow plugs, know they can be a problem

update,glow plugs tested, turned out to be fuse f11 in engine fuse box 15A

Hi

You might be interested to know that F11 (15 Amps) supplies five items known collectively as "Electronic Injection System Secondary Services". These are:

Throttle Body
EGR Solenoid Valve
Glow Plug Controller (Logic Section)
Lambda Sensor
Oil Vapour Heater

It's possible that something has caused excess current for long enough to make the fuse blow. One possibility is the Oil Vapour Heater which is a heating resistor (about 10 ohms) mounted within a breather hose on the RHS of the engine near the bulkhead. This is only really needed for very cold climates, so can be just left disconnected if it is playing up.

hi, he did mention it also fed something on the variable turbo, but this does not
affect my van as it is a 2.3 130hp.it is something to keep in mind about other items fed by the same fuse.
thanks for info from Anthony489