Speedometer Fix?

I recently let a friend install an aftermarket radio in my 02' galant. After install radio worked, but speedometer does not. All other dash gages work excluding the odometer that no longer tracks mileage. Didnot have correct wire harness at the time, so spliced factory cables. Now emissions saying EGR and Catalyst not ready to be tested; no error codes; car driven over 500 miles since test and retested with same results. How do I fix the speedometer without replacing a bunch of parts and is the emmissions failure related.