Speed sensor changed, now engine won't start

Hi Guys

I have a C3 2002 1400 i changed the speed sensor yesterday and now the car won't start all I did was take the old one out and replace it with a new one and when i tried starting it it just cranks and does not start, please help

Hi

Put the old one back in and see if it starts.

Also, what was the problem you had that led you to change the sensor.


I assume you don't have ABS on the car

Hi Arfur

Yes I did put the old sensor back but still not starting, and this car does not have ABS on it and the power steering was also getting harder to turn and when i read up about it they say the speed sensor also work the power steering and i was not getting any speed on the odometer

It sounds like you did change the right sensor for the problems you had

No ABS sounds right, thanks for confirming.

Putting the old one back in and making no difference sounds like an unconnected fault.

Read the codes stored with lexia to see why it won't start.

Hi Arfur

Ok i got home now and started looking around and what i found was when i took off the air filter i unclipped one of the main cables that run into the box that is mounted next to the battery all i did was push it back in and then the car started, i changed the speed sensor with a new one but the speedometer is still not working, thank you so much for the info you have given i hope this helps the next person.

Quentin wrote: ↑Wed Aug 31, 2022 3:48 pm i unclipped one of the main cables that run into the box that is mounted next to the battery

A flat aluminium box with 3 looms and connectors on it? That's the engine Electronic Control Unit (ECU). There should be latches on the connectors to hold the plugs to the receptacles so they cant pop out. Are the latches broken or missing?
I am not sure but I think the engine ECU might be connected to the speed sensor and from there the engine ECU puts that information on the "bus" for other ECUs (like the instrument cluster) to use.
If you've got one connector loose have you checked the others? See if they are loose or remove the connectors and see if the electrical pins have corrosion on them.

thanks, I will check these connectors as well and will revert back