P1351 fault code.

[Boxer]

Apologies if this done before - I haven't found what I need by searching the forum.
I have the P1351 code up, suggesting a fault in the heater plug system. Does anyone know if this is likely to be a relay or a heater plug fault? I cant find the relay - does anyone know where it is?

To be honest I'm inclined to get on and replace plugs and relay at 75k miles and with winter coming. Looks like only way is to remove valance at the base of the windscreen. Anyone had experience of this?

Lots of questions I'm afraid. Thanks in anticipation.

[Johny555]

Mines near the near side head light,sounds like glow plug relay

[brodfather11]

http://www.berlingoforum.co.uk/showthread.php?tid=1875

There is a wiring diagram from Rustscrat , it is for the glow plug relay etc, I think IIRC that the earth wire gives a few problems.

[Boxer]

Sorry - should have said it is a 2009 1.6 hdi 75bhp.

[Boxer]

Sorry - should have said it is a 2009 1.6 hdi 75bhp.

[Boxer]

Well I found the relay for the heater plugs. Nagares BDL/7-12 bolted to front of the fuse box. I've done a few checks and come to a conclusion, but would welcome any comment. First thing I noticed from the relay wiring diagram, (available on google search under Images - but I don't know how to post a link), is that the heater plugs are wired independently from the connector at the relay. So I was able to do a continuity check on the plugs from this connector down to the engine block. I found three plugs had resistance around 1.3 ohms, while one (cylinder 4) had resistance of around 10Megaohm. I believe this plug to be burned out.
This morning I removed a smidgen of insulation from the leads from pins 1 and 6 (cylinders 3 and 4 respectively) where they exit the relay and took voltage readings. With ignition off pin 1 showed a couple of millivolts and pin 6 showed 10v. This is connected to the plug with high resistance and I believe the relay is faulty, providing a constant 10 v to the plug, burning it out. When I started the engine, both pins went up to 14.1 volts on tickeover. After 3 minutes pin 1 reset to a couple of millivolts (end of post heating period) while pin 6 stayed at 10 volts.

Conclusion - I have a faulty relay which is setting pin 6 at a permanent 10v.
This has burned out plug on cylinder 4.
Solution - new relay, new heater plugs (not doing just one while I'm in there).

Comments welcome - hope this is of use to others.

[Boxer]

Completely lost with this. Replaced relay and still have a permanent 10-11 volts on the feed to glow plug on cylinder 4. I won't be replacing the glow plug until I can sort this. I don't understand how one outlet from the relay (two relays now) can be live and not the others.
Thinking that the 10v might be coming back from a short on the glow plug wiring I disconnected the relay and probed the line from the glow plug - it had 4mv. As soon as I connect the plug to the relay I get 10 v on cylinder 4's glow plug feed. This is without ignition on.
I am pretty sure the glow plug is faulty as it measures open circuit when I do a resistance check on that connection.

Looking back I think the poor running when cold started around when I replaced the inlet air flow meter, which I believe has a temperature probe attached. I back fitted the old sensor and got same voltage figures. Is it possible a faulty temperature probe can switch the glow plugs on - but why only one?

Is the 10 v some sort of fault indication system?

Any ideas welcome. Thanks.

[Peter Palmer]

I think the glow plugs are used to control emissions as well as starting so its entirely possible the could still be powered even with the engine running.

Have you measured the voltage at the pin of the relay with the lead disconnected so it cant be a back feed or anything, also try it with a proper load like a bulb or maybe an analogue multimeter to make sure its not just a spurious load, sometimes digital multimeters give false readings.

[brajomobil]

Completely lost with this. Replaced relay and still have a permanent 10-11 volts on the feed to glow plug on cylinder 4. I won't be replacing the glow plug until I can sort this. I don't understand how one outlet from the relay (two relays now)  can be live and not the others.
Thinking that the 10v might be coming back from a short on the glow plug wiring I disconnected the relay and probed the line from the glow plug - it had 4mv. As soon as I connect the plug to the relay I get 10 v on cylinder 4's glow plug feed. This is without ignition on.
I am pretty sure the glow plug is faulty as it measures open circuit when I do a resistance check on that connection.

Looking back I think the poor running when cold started around when I replaced the inlet air flow meter, which I believe has a temperature probe attached. I back fitted the old sensor and got same voltage figures. Is it possible a faulty temperature probe can switch the glow plugs on - but why only one?

Is the 10 v some sort of fault indication system?

Any ideas welcome. Thanks.

Air temp sensor is built in MAF. You can check inlet air temp with lexia. I'm not sure cheap OBD can show that.
I can check and post that info if you need it. That will rule out faulty temp sensor.
If the air is cold ECU will fire up glow plugs. ECU will not send electric power if there is no resistance on end wires.
Connect 55w light bulb instead faulty glow plug then measure voltage. Open one relay and check inside
for problems. Also make relay pinout schematic. Post it here on forum.

Best regards,
brajomobil

[Boxer]

Thanks for help. I will be away or 4 or 5 days,so will get back onto it then. I havent worked out how to post a picture or a link, but lots of images available in google under. Nagares bdl/7-12 showing pins.
Thanks again.