I checked with my service manual (page 8-3) on those codes and says,* ïgnition signal circuit malfunction , the* refers to ,"when two ignition signals or two injector signals are not frceived by ECM, the fail-safe circuit can notwork and ignition or injection is stopped". On the "detected failure condition area",CKP sensor(pick-up coil) signal is produced but signal from ignition coil is not produced continuous two times. In this case, the code c24, c25, c26 c27is indicated. On thre check for says;ignition coil,wiring/coupler connection, power supply from the battery, I asked a freind of mine and he told me to check with a different set of coil plugs since these are usual on them, ask a buddy to use his and test, GOOD LUCK,