Question

What causes the engine code P1259 on my 1998 Honda Civic EX?

Answer 1

P1259 vtec pressure switch circuit or vtec solenoid valve circuit

Dirty oil or low oil is the main cause for this problem. You can check/replace the oil and see if it help.

You can also do an engine flush before you replace the oil to clean out the dirt from the engine.

Answer 2

P1259 HONDA Code - VTEC System Malfunction

Read more: https://www.autocodes.com/p1259_honda.html