Ecu Fault Code Reading

[gary6303]

how can i wire in a led light so i can read the fault code on my c20let manta.

[HutchRoslin]

Will this be a permanent engine management light for your car?

Don't use an LED, the ecu doesn't see it and brings up the EML code. Just use a small filament lamp

[gary6303]

yes will be permanant light on, to let me know that their is an engine fault, and flash the light so can read the fault code.

[mantadoc]

You need to know if it is switched live or switched earth. Most Motronic I have come across are switched earth. No reason an LED won't work IF you have if pointing the right way with an appropriate resistor.

[mantasrme]

I've not done a 20let but always put one in on XE builds.

For the 20XE Pin 22 from the ecu brown/blue wire goes to a lamp and an ignition 12v feed to the other side

This should light with ign on and go out when started, will also light when there is an error code

I normally add a switch to enter diagnostics mode to allow checking of stored error codes

Not all issues put the warning light on some are deemed only minor but can cause running problems
For this you connect pin 13 brown/yellow to a switch and the other side to earth, so i can just flick the switch and check codes whenever i want

Not sure if the 20let is the same but wouldn't supprise me as the ecu system is the same, but worth checking the wiring colors

[gary6303]

without sounding stupid, the wires mentioned what colour block do they come from.