Calgary Jeep Association

4x4 Related Groups => Tech Talk => Topic started by: Mudhawg on October 31, 2009, 01:50:19 PM

Title: Diagnostic codes
Post by: Mudhawg on October 31, 2009, 01:50:19 PM

check engine light in the Xj has been on for a bit finally decided to figure out whats wrong

i got 12 51 56

now ive figure out 12 and 51 but no idea what 56 is? can anyone help?

12* Direct battery input to PCM was disconnected within the last 50 key-on cycles
51** Oxygen sensor signal input indicates lean air/fuel ratio condition during engine operation

Title: Re: Diagnostic codes
Post by: mike s on November 01, 2009, 12:54:41 AM

Check the blink count again and you'll probaly find that 56 is a 55. 12 is usually start of code list and 55 is end of code
list. The lean code is likely set from an exhaust leak from cracked exhaust manifold, vacuum leaks from pcv
system or possibly a faulty sensor.