Glowplug error

[Peter Palmer]

Dispatch 1.6 8V 2015.

It seems as soon as I fix one problem other one occurs. The latest is an error saying glow-plug preheat...

I've changed the glow plugs which was a job I was dreading but they came out surprisingly easy, one advantage of an engine covered in oil I suppose, I reset the error code and the engine light went out and stayed out for the day. However the next morning the error came back and the engine light was back on again, it was quite chilly and the temperature display read 4 deg.

I'm guessing that anything under 5 deg calls for glow plugs and if they don't work for any reason then it generates an error, if its above 5 deg then maybe they don't need to operate so no error is displayed. Is this likely now to be the relay that is faulty, the glow plugs were really cheap off ebay - £12.99 for 4.

[myglaren]

It may be that the glow plugs are not suitable and that seems a very low price.
Citroen and Peugeot recommend Beru glowplugs and supply then as OEM equipment.
NGK plugs are frequently criticised as they don't seem to work well with PSA engines.

These from Autodoc are £6.89 each although they may not be exactly the ones that you need, best to put your VIN in for a more accurate search.

[GiveMeABreak]

It depends on the fault code you had - some will refer to the plugs and others to the relay.

[Peter Palmer]

I'll have to go and check the code, I had a mess about today with it, all glow plugs are "in circuit" doing the test lamp method, the lamp lit up on all 4 of them, there is 12V at the relay and there is also 12V on one of the pins when you turn the ignition on, it goes back to zero soon afterwards. What I couldn't work out though is what the green/yellow wire does on the relay connector, its the other large pin next to the permanent 12V, I assumed it was ground but there isn't any connection to ground from that pin, or any others from what I could see, it must get its 0V from the casing.

I also tried to put my multimeter in circuit set on amps just to see what the plugs were drawing in case they are shorting out but it must be greater than 6A as it blew the fuse inside the meter and I only had a 6A one to hand. (the meter does up to 20A but I'd previously blown it up by forgetting to put the lead back in the volts connection before probing the mains.

I'm pretty sure its the relay that's faulty though, theres nothing much else to go wrong really, but why does it need to be so complicated.

[GiveMeABreak]

Not the best condition at the lower edge there....

[Peter Palmer]

Well that's annoying, I been out to check the code and because I've been paying with the relay getting various readings I've now got 3 codes and I can't remember what the original code was. I did try looking in the history but there isn't anything there as far as I can see, there are logs from 1-22 with today's date at the top but no mention of error codes if you click on them.

I did try an actuator test "engine preheat" but it said there wasn't any fault. Strange.

Just slightly off topic as I don't want to start another post, I bought some Eolys? fluid to top the tank up (not adblue, the other one) but when I undid the tank expecting it to be empty it seemed to be quite full which I thought was strange as I've done well over 100K miles and it was on 105K when I bought it. I tried the actuator test on that as well and it sounded like a ticking noise coming from the back, like a clock was in there. Is this what it should sound like?

[cit-rotti]

The function of the glow plugs and the glow plug control relay can be checked with a voltmeter and an ohmmeter.

However, an ampere DC current clamp is ideal for testing. However, only one cable at a time may be used in the clamp meter for testing.

The glow plug control unit always works when the engine is cold and only becomes inactive at a higher coolant temperature. However, pre-glowing itself is only indicated at corresponding minus temperatures. Pre- and post-glow times depend on the coolant temperature.

Although the power consumption of the entire relay could be checked on its positive feed line and the consumption on the respective feed lines to the plugs, this can be checked more simply via the negative terminal on the battery.

If the ignition is switched on when the engine is cold (cold cooling water), a total current flows. Depending on the coolant temperature, the glow plugs work for different lengths of time and are then switched off according to the coolant temperature. Each glow plug requires approx. 15 amps of current - a total of approx. 60 A. The current consumption slowly decreases depending on the duration of the glow process.

If the negative terminal is used, the total current of all active consumers is of course measured at the current clamp - after the glow plug control unit is switched off, the residual current required by the other consumers therefore remains. If the ignition is then switched on again, the ammeter of the current clamp must display 60A more and this 'current consumption must slowly decrease until the glow plug relay switches off - you can hear the noise and see it on the current clamp.

Greetings Wolfgang

[Peter Palmer]

Thanks for the explanation, I'm guessing if I go out now and start it then the error will be back so I will do soon. I have got a clamp meter but its in our other van so cant get to it until Monday or Tuesday. 15A will be why the fuse in my multimeter blew then, I'm tempted to just put a wire across it instead of the fuse, its only an old meter but its so easy to forget your lead is in the amps side of the meter when checking voltage and across the mains isn't pretty without fuse protection in the meter.

[GiveMeABreak]

Also, just to add, the glow plugs are rarely used except in minus degree temperatures, but are used for post-heating if commanded by the engine ECU for assisted regeneration if the conditions require it, in order to raise the exhaust gas temperature more quickly. So that is another function of the glow plugs.

[cit-rotti]

Thanks for the explanation, I'm guessing if I go out now and start it then the error will be back so I will do soon. I have got a clamp meter but its in our other van so cant get to it until Monday or Tuesday. 15A will be why the fuse in my multimeter blew then, I'm tempted to just put a wire across it instead of the fuse, its only an old meter but its so easy to forget your lead is in the amps side of the meter when checking voltage and across the mains isn't pretty without fuse protection in the meter.

The ammeter in a multimeter has its limits and can rarely be used in a 12V system because much higher currents are the rule there.

It must also be a DC current clamp and not an AC current clamp and, if possible, should be designed for 600A - if the power capacity is lower and is measured via the negative pole, then care must be taken to ensure that no starting process takes place. A starter motor alone usually requires around 150-200A and has a short-term breakaway requirement of 600A - sometimes even higher.

[Peter Palmer]

I'm actually an electrician so am fully conversant with multimeters etc. my meter is a Proster one I've had for years and I got it specifically because it does AC amps which not many multi-meters seem to do.

I got the code earlier and its P1532

However after a bit of googling the code I may well have found the culprit. recently I changed the injectors which meant shifting the wiring harness out of the way, this harness was held in place by a 8/10mm bolt to the back of the engine, I never bothered to put this bolt back in because the harness seemed quite secure without it but after reading a couple of threads it seems this bolt is quite a vital earthing point if I've read things correctly and I did mention in an earlier post that the green/yellow wire on the relay didn't have a connection to earth/ground/negative. I'll bet this is the earthing point for it.

[GiveMeABreak]

Usually people have to take their vehicles to the dealer in order to ensure bits are missing!

[Peter Palmer]

Well I was right about the earth, now the bolts back in the green/yellow wire of the relay is now reconnected to the earth as it should be, strangely though the fault won't clear now, where as it would before until the next day. The engine light has gone off though on its first start today but the outside temperature was 14 deg, not sure if the glow pugs would activate or not. I will have to wait and see if it comes back on again. Luckily though the cold weather is nearly gone so it might be ok for another year.

[RichardW]

Glow plugs are about 12A each, you'll need a hefty meter to measure that in series!

P1351 seems to be de rigeur on these engines, but doesn't cause any problems. 1352 puts the light on and has been flagged as related to that missing earth several times.