P0489 with engine mgmt light 2.0 HDI 136

[Dan car question]

The engine management light recently came on, on my 2007 C8 with the 2.0 HDI 136 engine. It went into limp mode, switched on and off and then it performed as normal again. I borrowed a CAN OBD2 code reader which gave P1351, P2408, P0489. I reset it to see which warnings came back. It came back a day later and I reset it again. A week or so later it cut out with no warning lights. I took it to a garage who identified a new code and the camshaft sensor was replaced which fixed the cutting out. P2408 remained and they recommended I took it to the main dealer for diagnostics. Having had a bad experience with the main dealer before, I found a Citroen/ Peugeot specialist who checked out all the codes and found P2408 has been recurrent for some time, but appears never to have caused problems. The specialist reset the codes and on the way back home the engine management light came on again. The CAN OBD2 scanner shows P1351, and P0489 which appears to relate to the EGR.

Any suggestions on what might be causing P0489 error would be much appreciated. The only noticeable issue with the engine which may be related, which has been present since I bought it 5 years ago, is that intermittently it has a very lumpy tickover, often after a long journey. The whole engine rocks back and forth and the vibration can be felt clearly in the cabin. Turning it on and off usually resets it.

[Huskyxantia]

Sounds like dpf needs cleaning

MAF sensors can act up when they start breaking down you can check the ohms resistance theres videos on youtube to show & tell what the resistance should be.
I had a 206sw 6 years ago always giving me grief that had allsorts changed & it still carried on playing up mine was glow plug near battery side snapped & left in the head by the former keeper once that was done it was fine , sold her on for a nice little profit as i needed a bigger estate.
Post back your findings as it helps others in here. Also Marc on here is tops for all sorts of stuff, well worth donating to for extra stuff aswell.

[GiveMeABreak]

...... Any suggestions on what might be causing P0489 error would be much appreciated. The only noticeable issue with the engine which may be related, which has been present since I bought it 5 years ago, is that intermittently it has a very lumpy tickover, often after a long journey. The whole engine rocks back and forth and the vibration can be felt clearly in the cabin. Turning it on and off usually resets it.

You need to provide your VIN (automasked on post submission) so any fault codes can be related to your specific engine ECU. Then I can provide your with the specific fault description as it relates to your vehicle.

[Dan car question]

Hi Marc

The VIN VF7**************[VIN obfuscated, can be read by forum staff]

Many thanks

[GiveMeABreak]

Ok, so here are the descriptors. Your P1351 fault is to do with either the glow plugs or the glow plug heater (relay). This is a common fault, and is not really anything to worry about at this point as it won't affect starting on HDi engines unless in extreme cold temperatures. They are also used to assist with particle filter regeneration by the engine ECU to help increase temperature. Focus on the other issues for now.

Fault Code:	P2408
Description of Fault:	Additive system: Fuel tank cap sensor signal fault. Fuel tank cap sensor signal fault (For 30 seconds).
Conditions for Fault to clear:	Ignition on
Downgrade Modes whilst Fault is active:	Deactivation of the forced regeneration of the particle emission filter
Symptoms:	None
Suspect Areas:	Fuel gauge Electrical harness Connector Built-in systems interface

Fault Code:	P0489
Description of Fault:	Position indicator signal of the EGR valve: Negative loop difference. EGR electric valve position copy is too far off the setting (Difference in position of -40% for a period between 2,5 and 10 seconds).
Conditions for Fault to clear:	Ignition on
Downgrade Modes whilst Fault is active:	Cutting of the EGR valve
Symptoms:	Jerking/stalling Smoke from the exhaust Lack of power Starting problem
Suspect Areas:	Electrical harness Connector Electric exhaust gas recycling valve

[Dan car question]

That's really helpful, thanks Marc. The car doesn't seem to have any symptoms related to P0489. I guess I could ask my local garage to check out the suspect areas. Looking at some of the other posts on the forum it seems that it could be quite difficult to pinpoint the actual cause.

[GiveMeABreak]

HI Dan(?). First of thank you for your Forum donation, much appreciated.

Any official parts info you need, please use this thread for donating members to request them

viewtopic.php?t=69962

There is also a members resources section where I have put up some 'how to' guides which I add to quite regularly.

viewforum.php?f=54

But back to the issues, yes, the fault codes can only offer a guide as a lot of the systems are inter-related so a fault in one can cause a fault to appear in another place.

At the age of your car though, It's probably a safe bet to assume that the EGR may need some attention if it's starting to stick. Although the vehicle has a self-cleaning operation at the end / start of each cycle to help prevent sticking, they will start to clog at some point and if you have had the same one in use for 15 years, then it may benefit from a replacement or a clean. But having said that, if it was me, I would consider cleaning the air intake manifolds too, as these can equally become clogged up over the years.

As for the plug detect harness issue:

Your vehicle could of been supplied with or without a plug detect harness, that is shown below Item (31), part: 1503CH which is no longer available from Citroen.

If you do have this system you may be able to see if your fuel cap has a magnet as shown which may indicate if this system is used or not. The other differences is are that the older system that I mentioned above also has a separate DPF additive ECU, where the later vehicles make use of the engine ECU to control the additive pump.

Above you can see the end of the plug detect harness at (7) and the magnet (8) on the filler cap. Again - I can't be 100% certain, as they only show 2 types of filler cap - a locking one and one without a lock. So it could turn out that they both have magnets on!

Unfortunately, as these solutions changed through production, they don't specify which system your vehicle has. In cases where the later system is deployed (without the plug detect harness), the warning fault code may be triggered if it is not physically there. So I can't be sure on this.

[Dan car question]

Hi Marc

Thank you very much for the extra details and suggestions. The mechanic that looked at it previously mentioned that the engine ECU controlled the additive pump. Would that make sense in that P2408 has been a persistent error without the engine management light, because it is just indicating it doesn't have the plug detect harness which isn't required anyway?

Dan

[GiveMeABreak]

It is possible. One would have to visually check for the harness to know for sure.

Your mechanic may be correct as I previously stated, but as I said this vehicle was produced with both systems. The other system has a separate additive ECU usually mounted behind the dash board. It is a Magneti Marelli EAS300 ECU - but having now checked diagrams I can see that the separate ECU is not shown on the fuel system parts diagram, so that would seem to confirm that the engine ECU is controlling the additive functions.

But I can't tell you for sure whether the harness fault is relevant to your vehicle or not unfortunately - as I think that would need a visual check to confirm and then a quick check over.

[Dan car question]

Thanks Marc. Since the eml came on I have started it a few times to move it to allow my other car in and out of the drive and I noticed it now no longer has the eml on. I reconnected the CAN OBD code reader it only shows P1351 and P0489, P2408 has disappeared. I drove it around 30 miles this weekend and the eml light is still off and it drives with no issues. I'm now wondering if the EGR is a concern or not.

[GiveMeABreak]

Just keep an eye on it as the EGR is controlled and will open and close according to need, so it may or may not come on again.