CONNECTOR AS 2681643 - Caterpillar

Use this procedure if any of the following conditions exist:
The Electronic Control Module (ECM) has been replaced.
261-13 is active.
Work has been performed on the engine drive train (front).
Illustration 1 g00899451
Schematic
The engine speed/timing sensors provide information to the ECM by generating pulse signals as the timing reference ring rotates past the magnetic pickups on the sensors.The secondary engine speed/timing sensor provides continuous operation of the engine if the primary engine speed/timing sensor fails. The loss of signals from both engine speed/timing sensors will prevent the ECM from actuating the injectors. To prevent any unnecessary down time, correct any problems with the speed/timing circuit as soon as possible.The engine speed/timing sensors are magnetic sensors that provide a frequency that is directly proportional to engine speed (rpm). A unique tooth on the timing reference ring passes by the engine speed/timing sensor. The engine speed/timing sensor produces a duty cycle output. This duty cycle provides the ECM with information on the crankshaft position.Timing calibration is accomplished by installing a probe into the side of the engine block and by performing the "Timing Calibration" on the Caterpillar Electronic Technician (Cat ET). The probe senses a special slot on the crankshaft counterweight. The probe is connected to the ECM through the P26 timing calibration connector on the engine harness.Note: Performing a timing calibration will not increase the available engine power.
Illustration 2 g00798969
Table 1
Required Special Tools
Part Number Description
6V-2197 Magnetic Transducer (Timing Calibration Probe)
7X-1695 Cable (Timing Calibration)
7X-1171 Transducer Adapter
9S-9082 Engine Turning Tool Test Step 1. Install the 7X-1171 Transducer Adapter
Turn the keyswitch to the OFF position.
Use the 9S-9082 Engine Turning Tool to put either the No. 1 piston or the No. 6 piston at top center. Then rotate the crankshaft in the direction that is opposite of the normal rotation for 60 degrees. Note: Normal engine rotation is counterclockwise as the engine is viewed from the flywheel end. Refer to Illustration 2.
Remove the timing calibration plug from the cylinder block. Note: If the engine is viewed from the flywheel side of the engine, the timing calibration plug is located on the left side. The timing calibration plug is located on the No. 2 cylinder rod pocket.
Install the 7X-1171 Transducer Adapter into the hole for the plug. Results:
OK - Proceed to Test Step 2.Test Step 2. Install the