0398822 JOHNSON CARBURETOR ASSEMBLY

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Schematic for the engine speed/timing sensors
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Left side view
(1) Engine
(2) Flanges
(3) Bracket
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Sensor assembly
(4) O-ring
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Left side view
(1) P400 connector for engine timing calibration
(2) J2/P2 connectors
(3) J401/P401 connectors for the primary engine speed/timing sensor
(4) J402/P402 connectors for the secondary engine speed/timing sensor
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P2 terminations for the engine speed/timing sensors
(P2-25) Primary engine speed/timing −
(P2-26) TDC probe +
(P2-35) Primary engine speed/timing +
(P2-36) TDC probe −
(P2-46) Secondary engine speed/timing +
(P2-47) Secondary engine speed/timing −
Table 1
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect the Cat® Electronic Technician (ET) to the service tool connector.
B. Turn the keyswitch to the ON position.
C. Start the engine and run the engine until the engine is at normal operating temperature.
Note: If the engine will not start, monitor the engine rpm on Cat ET while the engine is being cranked. Cat ET may need to be powered from another battery while the engine is being cranked.
D. Look for these codes on Cat ET:
190-08
342-08
Codes
Results: Engine rpm is not indicated on Cat ET. Proceed to Test Step 2.
Results: There is an active diagnostic code or a logged diagnostic code for the engine speed/timing sensor. Proceed to Test Step 4.
Results: Neither code is active or logged.
Repair: Refer to the appropriate symptoms in Troubleshooting, "Troubleshooting Without a Diagnostic Code".
STOP
2. Check the Installation of the Sensor Assembly
A. Turn the keyswitch to the OFF position.
B. Visually inspect the sensor assembly without removing the sensor assembly from the engine. Flanges (2) must be flush against engine (1) in order to ensure proper operation.
Inspect bracket (3). Verify that the bracket allows the flanges to be flush against the engine.
Verify that the bracket is not bent. If the bracket is bent or if an obstruction is preventing the sensor assembly from being installed correctly, the engine will not start.
Note: The bracket cannot be replaced separately.
C. Remove the sensor assembly from the engine.
D. Ensure that one O-ring (4) is installed on each sensor. Check the O-rings for damage. Replace the O-rings, if necessary.
Sensor Assembly
Results: The sensor assembly components are OK. Proceed to Test Step 3.
Results: At least one of the sensor assembly components is not OK.
Repair: Replace the sensor assembly.
3. Inspect the Electrical Connectors and the Wiring
A. Thoroughly inspect connectors (1), (2), (3), and (4). Refer to Troubleshooting, "Electrical Connectors - Inspect".
B. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the engine speed/timing sensors.
C. Check the torque of the allen head screws for the ECM connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect".
D. Check the harness and the wiring for abrasion and for pinch points from each sensor back to the ECM.
Electrical Connectors and Wiring
Results: The harness and connectors appear to be OK. Proceed to Test Step 4.
Results: The connectors and/or wiring are not OK.
Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.
STOP
4. Measure the Sensor Resistance through the Engine Harness
A. Disconnect the J2/P2 ECM connector.
B. If you are troubleshooting a problem with the primary engine speed/timing sensor, perform the following procedure:
1.