I bought this ps9 off ssl2k and it through a code 4 (map sensor) which i thought was strange because it never thew the code with my pr3. So, I took off the back plate to look at the chipping job and I found a jumper. My question is what does this jumper do and should i clip it? I never have heard of this before.

 

thats cuz someone pulled a trace when chipping the ECU

 

yup...

not sure why/if that would affect/cause the code 4 though

does it cause the car to run funny when you start it? (limp mode) or does it just blink?

 

it ends up that for what ever reason the ecu pin outs make a weak connection with one of the pins, hence the code. The ecu is chipped correctly but rediculously sloppy. so when the harness is moved it dosent make contact with one of the pins and throws code 4. this ps9 works but I hope to find one at the junk yard.