406 Speedo Fault

jonesgh · Unread post by **jonesgh** » 16 Aug 2003, 19:48

I have a problem with the Sagem speedo in my 406 coupe in that it only works intermittently. I have also noticed that the car seems to drive differently when it isn't working in that it lurches. Does anyone have any idea what's going on?.

wheeler · Unread post by **wheeler** » 16 Aug 2003, 23:41

more than likely an intermitantly faulty road speed sensor at the back of the gearbox,this is what gives the speedo its reading.the engine ECU also uses infomation from this sensor which would explain the poor running when the speedo cuts out.

jonesgh · Unread post by **jonesgh** » 17 Aug 2003, 13:14

Thanks for that. Would a faulty speed sensor be recorded in the engine diagnostics?

wheeler · Unread post by **wheeler** » 17 Aug 2003, 22:57

there may be a fault in the ECU memory because its loosing road speed info,you wont always get a fault code though,even if it comes up with a speed sensor fault it doesent neccisarily mean its the sensor thats at fault,it may be the wiring,the fault code just means there is a loss of information from it.my guess is a faulty sensor though

jonesgh · Unread post by **jonesgh** » 17 Aug 2003, 23:38

Thanks again, you seem very knowledgable about these things. Where would you recommend that I take the car to get this fault looked at? Is a Peugeot garage the best bet or are there specialists in this kind of thing?