The Engine Control Module (ECM) detects the following conditions:

•The ECM detects a low current condition (open circuit) for one second while the ECM is attempting to energize the solenoid for cylinders 3 and 4.
•The engine retarder switch is in the low or high position.

Probable Causes:

1) ECM Connection/Harness
2) Harness between the ECM and valve cover base
3) Engine retarder solenoid failure
4) Harness under valve cover
5) ECM Failure
6) Harness at bulkhead connector