C5 x7 HDI DV6TED4 engine management problems.

[chunky2778]

Hi all, my C5 has started to play up on me.

The clamp at the joint between turbo and dpf has been leaking slightly for a while. Hissing getting worse from it so decided to replace it.

Since I've replaced it the hissing is probably worse, flat on power but only intermittently, took it on a forty mile round trip this evening and again drove ok sporadically, cruise control worked on way there but refused on way back, no EML or anything.

Rechecked my work thinking there was a leak from the clamp I'd fitted, no carbon around it, also when I fitted the clamp I loosened the two nuts holding the dpf to the block so hoping it should've sealed correctly?

Quick trip to the shops this evening, depollution error and EML on. Wouldn't say a massive loss of power but not right. Hissing sounds from low down like it's under the car now, from what limited I could see there's no leak from dpf to flexi.

I only have a basic code scanner but it's showing P0100 MAF or VAF circuit.
P3008 unknown DTC manufacturer control
P1351 unknown DTC manufacturer control

Any ideas at all please?

[GiveMeABreak]

You can ignore the P1351 - that's to do with the Glow Plugs. It means the relay is supplied with power, but the glow plugs are not. They are only really needed in extreme cold on an HDi, or to assist with DPF regeneration if necessary.

Your other fault code is detailed below:

Fault Code:	P3008
Description of Fault:	Flowmeter signal : Air flow too strong. Negative gap for 8 seconds between the theoretical air flow and the measured air flow as calculated by the ECU : The measured air flow is greater than the theoretical air flow by 71% to 76%. Conditions of activation of the diagnostics: Consult the associated contexts for the Pcode forwarding conditions: Engine speed between 1400 and 2400 rpm Turbo pressure greater than 725 mbar Atmospheric pressure higher than 725 mbar EGR butterfly open (doseur) Fuel flow lower than 3 mg/stroke Exhaust gas recycling valve closed Coolant temperature between 60°C and 110°C Air flow sensor air temperature between -20°C and 70°C
Conditions for Fault to clear:	Driving for 5 minutes
Downgrade Modes whilst Fault is active:	Use of the flow calculated Cutting of all the EGR butterfly actuators (Turbocharger air cooler); Electric exhaust gas recycling valve; Bypass valve (Intake air heater ) in all operating modes Inhibiting of the diagnostics relating to the air flow Change to "easy move" torque invalid (Deactivation of automatic mode for the electronic parking brake)
Symptoms:	Lack of power
Suspect Areas:	Electric exhaust gas recycling valve Air flow sensor information incorrect Air intake Turbocharging pressure sensor Leak downstream of the compressor

[chunky2778]

You can ignore the P1351 - that's to do with the Glow Plugs. It means the relay is supplied with power, but the glow plugs are not. They are only really needed in extreme cold on an HDi, or to assist with DPF regeneration if necessary.

Your other fault code is detailed below:

Fault Code:	P3008
Description of Fault:	Flowmeter signal : Air flow too strong. Negative gap for 8 seconds between the theoretical air flow and the measured air flow as calculated by the ECU : The measured air flow is greater than the theoretical air flow by 71% to 76%. Conditions of activation of the diagnostics: Consult the associated contexts for the Pcode forwarding conditions: Engine speed between 1400 and 2400 rpm Turbo pressure greater than 725 mbar Atmospheric pressure higher than 725 mbar EGR butterfly open (doseur) Fuel flow lower than 3 mg/stroke Exhaust gas recycling valve closed Coolant temperature between 60°C and 110°C Air flow sensor air temperature between -20°C and 70°C
Conditions for Fault to clear:	Driving for 5 minutes
Downgrade Modes whilst Fault is active:	Use of the flow calculated Cutting of all the EGR butterfly actuators (Turbocharger air cooler); Electric exhaust gas recycling valve; Bypass valve (Intake air heater ) in all operating modes Inhibiting of the diagnostics relating to the air flow Change to "easy move" torque invalid (Deactivation of automatic mode for the electronic parking brake)
Symptoms:	Lack of power
Suspect Areas:	Electric exhaust gas recycling valve Air flow sensor information incorrect Air intake Turbocharging pressure sensor Leak downstream of the compressor

Thanks very much, sorry I'd forgotten I'd posted this and been ill since.

It's still playing me up. I bought a better scanner that does DPF regens which seemed to cure for a while then back to square one other than no DPF codes any more.

It started coming up with (from memory) a P1457 or similar that said DPF not present or punctured?

It doesn't do that anymore but every now and again it put the EML on and there's this hissing all the time.

Is it worth me taking off the DPF and back flushing it?

When it says air leak downstream of the compressor that's a boost leak like split intercooler etc isn't it?

[GiveMeABreak]

I think you're referring to the turbo here? A leak in the turbo air hose can cause rasping, lack of power, spluttering etc. depending where it is and how big the split is.

[chunky2778]

Thanks Marc, yeah I took the leak downstream of the compressor in the last sentence of the diag tables you posted to mean a leak on the intake side of the system after the turbo compressor.

The hissing noise is intermittent, I think I may have a blocked or partially blocked dpf and am considering removing and back flushing.

Also, I've changed the fuel I use and unless coincidental then it's running a lot better. After I'd filled up it must have regenned as it was smelling really acrid and badly of fumes.

The EML popped on again today, the pattern seems to be the last three times it's done it I'm driving downhill on the overrun.

[MattBLancs]

I think I may have a blocked or partially blocked dpf and am considering removing and back flushing.

I've tried DIY cleaning of a DV6 DPF with pressure washer. Also with garden hose and compressed air (thought bubbles of air rising up through a water filled DPF might dislodge stuff well). Also tried soaking in a mild degreaser. Some soot dislodged but not massive clean out.

I've posted some YouTube videos I found showing the proper equipment flushing out a DPF professionally. It fair to say the volume and pressure of water able to be generated that the DPF is subjected to doesn't seem very easy to replicate at home, sadly.

Will try and find them and you can see the scale of what you need to achieve.

Does sound a bit like DPF is blocked, from your description, to me.

[chunky2778]

Thanks Matt,

I've watched a few videos myself and I keep seeing wynns off car dpf cleaner mentioned.

Might give it a go.