P0687 P0687 code definition A P0687 code (http://bestride.com/engine-trouble-codes/P0687) (http://bestride.com/engine-trouble-codes/P0687) is stored when the PCM (powertrain control module) detects an incorrect, abnormal, or erratic voltage reading from the relay control circuit that supplies it with its power. What the P0687 code...
