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Matt
Matt, Mechanical Engineer
Category: UK Car
Satisfied Customers: 20598
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I live in Spain I have a 2004 vaneo 1.7 cdi family I believe

Customer Question

Hi Paul i live in Spain I have a 2004 vaneo 1.7 cdi family I believe this is the same engine that is fitted to the 1.7 cdi A class I am getting EPC warning lights and a loss of power. I have had the car plugged into a diagnostic computer and the descriptions, these have been translated from Spanish so if they are a little strange that is why. I hope you can help
CAN: Communication error with DAS (drive Authorisation system)
Intermittent
CDI modulates control: feed
Signal too low
Intermittent
Control air pressure load
positive control variation
Intermittent
Thanks *****
Alicante Spain
Submitted: 11 months ago.
Category: UK Car
Expert:  Matt replied 11 months ago.

Hello

the lack on CAN communication usually means a lack of power to the ECU so 1st check the ECU poewr supply / fuses and if OK then check the connections to the EGR valve, if either the vacuum pipe of electrical connection are damaged / corroded then the EGR can be on all time which certainly will hurt performance. Its also possible that its a fault with the EGR valve so its worth removing the valve and cleaning it out with brake cleaner, if it looks particularly clogged then replace it.

If this is OK then check the small vacuum lines to the turbo and its connected control solenoid on the bulkhead, any cracks or leaks can give turbo issues and its best to have the boost pressure measured actually measured with a boost gauge to check that the turbo is healthy and that the sensor is reading correctly

If its a variable vane turbo (they’ll be an actuator on the turbo body - but not a wastegate) then check its vacuum pipework as above and check the connections to the diaphragm / solenoid valve

Also worth checking that the glow-plug relay is switching off as they can stick on and leave the glow plugs also on - on some cars this can force it into limp home

Also worth considering adding a bottle of injector cleaner into the tank as a clogged injector nozzle will reduce power and give poor combustion - the next stage on from this is to remove all the injectors and have them ultrasonically cleaned and flow checked

Also check all the high pressure hoses post turbo/s for any split hoses or cracked metal pipes, also check the ends of the intercooler as its not unheard of to pop the end caps off under high boost.