Q: i did the manual code check on my jeep. the numbers came up in this order. 12,52,51,55. can someone tell me what these codes mean.
A: Each code code 12 one flash, pause two flashes NO reference pulses to ECM code 51 five flashs pause one flashes PORM problem Diagnosis should be preformed by a dealer, Code 52 no such code Code 55 five flashes/ Five flashes Reference voltage problem check for a short circuit to groung on the wire to EMC terminal 21. possible faulty EMC or oxygen sensor