SHAFT-DRIVE 7Y4251 - Caterpillar

Engine:
3508B (S/N: S2A1-UP; CBB1-UP; CNB1-UP; S2B1-UP; S2D1-UP; YAD1-UP; ZAD1-UP; S2E1-UP; S2F1-UP; 7AF1-UP; PTJ1-UP; 2BM1-UP; 3DM1-UP; 4GM1-UP; 7SM1-UP; PTN1-UP; 6PN1-UP; 5PS1-UP; 1TW1-UP; 2HW1-UP; 3DW1-UP; 5KW1-UP; BGX1-UP; BPX1-UP; CTC1-UP; 1FZ1-UP)
Power Module:
PM3508 (S/N: BLM1-UP; BPY1-UP)
The Electronic Control Module (ECM) has the ability to calculate mechanical differences between the position of the timing gear and the positions of the pistons. The engine speed/timing sensor signals the position of the camshaft when the teeth of the camshaft timing gear pass the sensor. This helps the ECM to determine the engine timing. If the timing is not properly calibrated, the engine may experience performance problems. Timing calibration is required after any of the following circumstances:
The ECM has been replaced.
The engine speed/timing sensor has been replaced.
The timing gear and/or the rear gear train have been removed or adjusted.
The timing gear and/or the rear gear train have been replaced.
One or both of the camshafts have been replaced.Note: The 261-13 Engine Timing calibration required diagnostic code is generated only for an ECM that has never performed a timing calibration. For instructions on performing the timing calibration, refer to the engine's Troubleshooting manual. If the Caterpillar Electronic Technician (ET) indicates "CALIBRATION UNSUCCESSFUL", perform the prescribed troubleshooting.