C4 VTR 2013 Brake Issue

[Daibach]

Scary situation. Brakes are very good around town, now I've got used to Citroen's short pedal travel and sharp braking BUT ( it's a big but!) at the end of a run say at 50mph for a while, the pedal goes down a lot more and the brakes feel like there is nothing happening, then suddenly they come on very sharply, almost like a crash stop. I've got an idea it might be caused by a vacuum leak, but can anybody help please? It is making the car very scary to drive, since it's impossible to judge braking distances.

[the2ems]

I’m with you on the pedals. And I’ve considered getting shoes specifically for driving.

[GiveMeABreak]

Get it diagnosed properly to see if there are any fault codes coming back, but vacuum is a possibility as well as it not having been bled properly (needs to be done on both circuits and with a diagnostic tool for the ESP system).

[Daibach]

Diagnostics... I've got a basic U480 fault scanner and it's come up with P1337 and P2074 and also potential P2074. Could these be related to the brake problem? There's no warning lights coming on.

[GiveMeABreak]

I've split this off from the Introductions thread into the Citroen Technical Thread.

[GiveMeABreak]

Let me have the VIN and I'll take a look at those codes as they relate to your specific vehicle. Please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff.

[Daibach]

VIN NO. VF7**************[VIN obfuscated, can be read by forum staff]

[GiveMeABreak]

You listed two of the same fault codes, but here are the descriptors:

Fault Code:	P1337
Description of Fault:	Combustion misfiring (impact on catalytic converter): Injector cylinder no.1. Ignition misfirings on cylinder 1 that could damage the catalytic converter. Conditions of activation of the diagnostics The following conditions have to be met: - Engine management ECU in main triggering phase - Engine speed above 500 rpm and below a threshold defined in the engine ECU - Torque below a threshold defined in the ECU - The crankshaft and the camshaft are synchronised
Conditions for Fault to clear:	Switch off the engine and restart, in order to re-inject into the cylinders following the detection of misfirings
Downgrade Modes whilst Fault is active:	Cutting of cylinders above a detection threshold Deactivation of richness regulation Deactivation of checking of the canister purge Switching on of the warning lamp and/or warning message: Warning lamp MIL
Symptoms:	Starting impossible Starting difficult Idle unstable Idle speed too high Lack of power Engine hesitation Emissions outside the norms Excessive fuel consumption
Suspect Areas:	Programming of the autoadaptives Fuse Spark plugs Ignition coil Earth point Connectors Fuel injector 1 Engine compressions Variable valve lift system Electrical harnesses

Fault Code:	P2074
Description of Fault:	Inlet pressure regulation: Pressure too high. Inlet manifold vacuum regulation diagnostics. Conditions of activation of the diagnostics: Pressure regulator loop in the inlet manifold at the limit.
Conditions for Fault to clear:	The pressure regulator loop in the inlet manifold succeeds in adjusting the pressure
Downgrade Modes whilst Fault is active:	Possible starting of the fan assembly Switching on of the warning lamp and/or warning message: Warning lamp MIL
Symptoms:	Unstable idling Stalling at idle Engine hesitation
Suspect Areas:	Oil filler cap Dipstick Air line Electrical harness Canister discharge solenoid valve Fuel vapour recycling pipe Oil vapours recycling pipe Motorised throttle unit

[Daibach]

I’m with you on the pedals. And I’ve considered getting shoes specifically for driving.

And that's exactly what I have done. I had some old Slazenger indoor trainers which I found were good for driving, so I bought today's equivalent from Sports Direct yesterday. Not quite as good, but hopefully they will soften up.

[GiveMeABreak]

Perhaps a pair of these pinkle wickers gents?

[Daibach]

I'm beginning to think I know exactly where to position those on the Salesman I bought the car from!

[PaulC5]

Off hand, it might be worth checking the handbrake is adjusted properly. if over adjusted handbrakes can stop auto adjusters working which might lead to more pedal travel needed.
We've had a few C4s and I have caught the wrong pedals at times and had forgotten about it until reading this and I only wear size sevens. We changed our last one 4 years ago. They were good comfy cars with good fuel economy, both things better than our current 308 1.5 hdi.

[Daibach]

Thanks for that advice Paul. The car's going into my local garage to check out the brakes tomorrow, so I'll pass that info on to them. Just come back from car sales yard & workshop, where they have replaced leaking passenger side drive shaft oil seal. Funny they didn't spot that when doing the MOT 2 weeks ago !! (" all cars come with a new 12 months MOT" ). No fails or advisories on MOT though.

[Daibach]

Well, the car is back from the garage. Brakes have been stripped out and checked, sliders greased and brakes bled. Apparently there was a little bit of air in the rears but nothing of importance. I've been out on a test drive and I notice some pedal movement before the brakes come on. Is this normal does anyone know? I'm also told I should have an engine undertray. I see these advertised on ebay at a range of prices. Whilst ebay tells me a number of them will fit my car are there different types for different engines? Mine has the 1.6 VTi 120 petrol engine. Also does the undertray fit directly to the chassis ( for want of a better word) of the car or will I need other bits ( which are probably not there either) to fit it? Of course, the car yard doesn't want to know ( " not all of this model had undertrays sir" ) so thanks for everyone's patience with me on this.

[GiveMeABreak]

He's correct, it's mostly the diesels that have them fitted. Whether these also fit to the front air deflector I can't be 100%. Please see parts info requests below (and I have your VIN already for this vehicle).

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