warning lights c4 grand picasso

[jdix1966]

hi everyone i have a problem with my 2014 c4 grand picasso getting fault code p0809 and u1208 i have replaced clutch master cylinder twice thort first one was faulty but problem still there but strange thing is if i put in reverse manual box push start button i get no warning message to check engine and parking brake and i can then clear faults but as soon as i take out of reverse they come back when i check data for clutch pedal it says released even when pushed down percentage reades 100 percent when fully depressed has anybody come across this before i also replaced reverse switch checked the 3 wiers on switch for continuity all ok 5v ref there and ground is ok 5v on signal wire hope someone can help thanks

[GiveMeABreak]

Best to provide your VIN so we know exactly what engine and equipment you have. U1208 is a comms / data network fault as is a generic code that can relate to different systems - so we need the context in which the fault appears - under which system does the fault appear? Gearbox, Engine, ESP, etc.

Considering the other behaviour you mention, you may be focussing on the mechanical and not the other potential issues like the electrics or connectors, which is what the U1208 code may be trying to tell you.

Fault Code:	P0809
Description of Fault:	Clutch master cylinder position measurement: Signal not plausible. Description of the diagnostics: Fault of plausibility detected on the clutch master cylinder position sensor.
Conditions for Fault to clear:	Ignition on
Downgrade Modes whilst Fault is active:	Reversible deactivation of the vehicle cruise control Deactivation of the "Stop and Start" function. Switching on of the warning lamp and/or warning message: "SERVICE" warning lamp.
Symptoms:	Jerking/stalling Absence of automatic stopping of the internal combustion engine Problem with automatic restarting of the internal combustion engine Malfunction of the Stop and Start switch or its LED Starting problem
Suspect Areas:	Clutch master cylinder position sensor Electrical harness Connectors

[jdix1966]

ABS or ESP -- ESP90//
VIN: VF7**************[VIN obfuscated, can be read by forum staff]
Engine ECU -- HDI_SID807_BR2 ( 1 DTC )
DTC
Description
P0809
Clutch master cylinder position measurement -- Signal
implausible
Status
Permanent fault
ABS or ESP -- ESP90 ( 1 DTC )
DTC
Description
U1208:81
Inter-systems CAN (Engine ECU) -- Data received invalid
Status
Permanent

[jdix1966]

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

[GiveMeABreak]

Fault Code:	U1208 81
Description of Fault:	Communication with the engine management ECU: Data invalid. Fault in communication with the engine ECU : Value received invalid. The time for recording the fault code is 500 milliseconds
Conditions for Fault to clear:	Ignition on (For at least 30 seconds)
Downgrade Modes whilst Fault is active:	Possibility 1 - Deactivation of the traction control function with action on the engine torque (EASR) - Deactivation of the ESP function - Deactivation of the indirect deflation detection function (DSGi) - Deactivation of the ESP function in deceleration phase (MSR) - Deactivation of the hill start assistance function - Deactivation of the "Stop and Start" function - Deactivation of the emergency collision braking function - Deactivation of the traction control function (ASR+) (*) - Deactivation of the descent control system Possibility 2 - Deactivation of the traction control function with action on the engine torque (EASR) - Deactivation of the ESP function - Deactivation of the ESP function in deceleration phase (MSR) - Deactivation of the emergency collision braking function - Deactivation of the traction control function (ASR+) (*) - Deactivation of the descent control system Possibility 3 - Deactivation of the hill start assistance function Switching on of the warning lamp and/or warning message: ESP warning lamp, Emergency collision braking function fault warning lamp, Descent control system fault warning lamp, "SERVICE" warning lamp.
Symptoms:	Malfunction of the emergency collision braking function Poor behaviour of the vehicle on braking Malfunction of the descent control system
Suspect Areas:	Engine management ECU Connectors Intersystems CAN

[jdix1966]

Thanks for info marc will check the. Suspect areas i was just a bit confused about the when in reverse every thing was normal

[maciejwrc]

Hi all. I have a question for jdix1966. I have the same symptoms and fault codes as you. The clutch master cylinder has been replaced. What was the problem in your case?

[Yusef]

Hello, I have the same pb I replace all components but start only in reverse. Please can you tell me what was your problem please. Thanks for all.

[Yusef]

Nobody to help me

[RichardW]

You will need to get it on a diagnostic machine to see if there are codes present, and then what live data is present. I can't really think why it would start in reverse but not neutral or a forward gear - unless the reverse light is providing a ground path that is not otherwise there.

[Yusef]

Thanks for your help Richard., I am going to see that now.

[Yusef]

Ok with diagbox I clear the fault and I reset clutch master cylinder, now all is OK thank you.