COVER 5N1939 - Caterpillar

System Operation Description:The master Electronic Control Module (ECM) has the ability to calibrate the mechanical differences between the Top Center (TC) of the flywheel and the TC of the timing gear on the left rear camshaft gear. A magnetic transducer signals the TC of the flywheel to the master ECM when the TC hole on the flywheel passes beneath the transducer. The engine speed/timing sensor signals the TC of the timing gear to the master ECM. Any offset between the TC of the flywheel and the TC of the timing gear is stored into memory.Calibration of the timing is required only after the following circumstances:
The master ECM has been replaced.
The speed/timing sensor has been replaced.
The timing gear and/or the rear gear train have been adjusted.
The timing gear and/or the rear gear train have been replaced.Note: The "261-13 Engine Timing calibration required" diagnostic code is generated only for a master ECM that has never performed a timing calibration.The calibration procedure is initiated with the Caterpillar Electronic Technician (ET).Test Step 1. Install the Transducer
Illustration 1 g00894217
(1) P50 connector (2) 6V-3093 Transducer Adapter (3) 6V-2197 Magnetic Transducer (4) 7X-1695 Cable
Set the engine control to the OFF/RESET mode. Remove the timing calibration plug from either the left side or the right side of the flywheel housing. Install the 6V-3093 Transducer Adapter into the hole.
The timing hole in the flywheel must not be aligned with the hole for the transducer. The transducer will be damaged on engine start-up if the transducer is installed through both holes. Rotate the flywheel for more than 10 degrees before or after the TC position in order to move the flywheel hole away from the hole for the transducer. Always confirm that the holes are not aligned.
Make sure that the hole in the flywheel housing for the transducer is not aligned with the timing hole in the flywheel. Remove the protective end cap from the 6V-2197 Magnetic Transducer. Insert the transducer into the adapter until the transducer contacts the surface of the flywheel. Move the transducer 1 mm (0.04 inch) away from the surface of the flywheel. Tighten the nut on the adapter in order to secure the transducer in place.
Connect the one end of the 7X-1695 Cable to the transducer. Connect the other end of the cable to connector P50 inside of the terminal box.
Set the engine control to the STOP mode.
Connect Cat ET to the service tool connector on the terminal box. For instructions, refer to Troubleshooting, "Electronic Service Tools". Start Cat ET.Results:Continue to the next test step.Test Step 2. CalibrationNote: A two-step process is used to calibrate the signal for the speed/timing sensor. The new timing reference is calculated first. The reference is based on the signals from the transducer and the speed/timing sensor. Next, the new timing reference is programmed into the permanent memory of the master ECM.
Start the engine. Operate the engine at the rated speed and load.
Select "Service" from the main menu on Cat ET. Select "Calibrations" from the menu.