Trouble Code Charts
TROUBLE CODE 51
Indicates that calibration PROMs are not being read properly by the ECM. Check PROM installation (backwards, bent or missing pins). Replace as needed. If installed properly, turn ignition off for 10 seconds and check for code 51. If code remains, replace PROMs. Repeat procedure and check for code 51 again. If code remains after replacing PROMs, replace ECM.