Possible causes – Ignition Coil No. 4 harness is open or shorted– Ignition Coil No. 4 circuit poor electrical connection– Faulty Ignition Coil No. 4– Faulty Engine Control Module (ECM) When is the obd code mean? The P1315 code is for the ignition coil No.4 and is set when there is no IGF signal to…