Code 41, Cylinder select error
Due to the same ecm being used for different engines, it is important that the proper prom is installed for the particular engine, a incorrect prom, not installed properly, or faulty. Another cause is the pins of the harness are not properly connected to the appropriate pins on the ecm, and/or the grounds could be open. For V8 applications, ecm pin D3 is grounded.
| B12 Use 4 cylinder input | D3 Use 6 cylinder input |
| 4 cylinder Ground | 4 cylinder Open |
| 6 cylinder Open | 6 cylinder Open |
| 8 cylinder Open | 8 cylinder Ground |
The chart above shows the appropriate pins on the ecm that need to be grounded for proper engine family.