Code 40 & 50

Code 40 - MISFIRE BANK A - left bank
Code 50 - MISFIRE BANK B - right bank

If both fault codes are displayed check the following components common to both banks:

Distributor cap
Rotor arm
Coil
Electrical connections
Pick-up (air gap)
Amplifier
Injectors - if code 34 bank A or 36 bank B displayed.


If either fault code 40 or 50 is displayed, check components applicable to the particular bank that the misfire has occurred on:

Spark plugs
HT leads
Distributor cap
Injectors - if code 34 bank A or 36 bank B displayed.