Ok guys

a Computer issue anyone offay with the workings of the Cambus on ford focus titanium 09

 

I am getting issues whilst driving, idle - I can be driving and nee nah nee nah the alarm goes off saying engine malfuntion then my odo and rev counter drops momentarilly then comes back on... i am still able to drive the car but then the ESP light comes on. IS the car able to operate while the PCM is offline? sort of a manual mode? it goes into limp mode but a simple restart of the engine clears this..

i am wondering if it is related to the ESP? as i have full esp func  before this error occurs... i have have this go off at random times over various terrains, i cant pinpoint it down. 

 

Torque pro will list the error as powertrain contol issue, "theft detected" ?? i didnt steal it honest guvnah

 

sometimes i dont even get to fire up the engine. as i can hear the fuel pump prime but on ignition nothing.... no starter motor or anything... (full power tho) a simple open up the bonet and let it fall shut seems to knock something to make it work....?????

 

I am stumped any suggestions please

Can High/Low Voltages

CANbus is a communication network. Measuring Voltage on a communication network does not make any sense. The only thing that can be measured on a CANbus network is resistance. Both ends of the CANbus network have a termination resistance of 120 Ohm. The reading between the High and Low wire of the CANbus network should be approximately 60 Ohm (2 x 120 Ohm in parallel = 60 Ohm).

 

Being a Focus MK2.5 the problem is most likely caused by a defective instrument cluster. This is a well known classic problem on the Focus MK2/MK2.5. 

is it?

 

because i can full drive... albeit limited acceleration once it screems at me, its screemed engine malfunction and more recentlt transmission malfunction... but i reset bu swittching off and on and its back to normal for a bit

 

would the instrument cluster throw up faults about theft detected and clutch sensor 

 

"P0704 Ford Description

When the clutch pedal is depress the voltage signal from the clutch switch to the Engine Control Module (ECM) is low. If the ECM does not see this change from high to low when the vehicle is over 0 mph, the ECM sets code P0704. 
"

 

any reason why it wont allow me to fire up sometimes and just screams at me? i can hear a lift pump engage on key turn and a relay click off on switching off in the front of the enginebay

 

 

at the moment i have many ideas but none solid

any id

as far as i was aware canbus high and lows should add to 5v

The instrument cluster is a key part of the PATS immobilizer system. A defective instrument cluster can prevent the car from starting or even switch the engine completely off when driving. Missing communication between the instrument cluster and the PCM as a results of bad soldering connections usually results in a "Theft Detected" warning message.

Both the throttle pedal and clutch pdal are directly connected to the instrument cluster. The instrument cluster converts the analog sensor signals to digital CANbus messages which are communicated to the PCM. Bad soldering connections can either cause inconsistent analog data or even no communication at all. Both will result in a "Engine Malfunction" message.

 

The difference between the HS CAN + and HS CAN - is usually 2 Volts. 3.5 Volts between the HS CAN + and ground and 1.5 Volts between the HS CAN -  and ground is quite common. However the voltage on the CANbus wires does not say anything about the communication. The voltages can be perfect while there is no communication at all. Apart from this measuring voltages on a CANbus network using a cheap voltmeter can in some cases even cause damage to the CANbus modules.

 

 

thankyou for this, this explains a lot of my faults

 

 i found this video too which confirms some too...

 

question is... do i repair this myself or send it to a garage to be repaired and they try and sting me for something else? i need a car so wonder if there is like any drop in centres for this?

anyideas where i can find part nuymbers for this before ripping out my car? ie over laptop or...

 

If anyones still reading this solved this common fault with the soldering as per the video

 

on the outter pins, resoldering it closed the cracks causing all the fake issues