0432293 JOHNSON LEVER AY

Table 1
J1939 Code and Description Comments
190-8
Engine Speed Sensor : Abnormal Frequency, Pulse Width, or Period The engine speed from this sensor is ignored.
The code is active.
The code is logged if the pattern from the timing ring returns for five seconds.
637-11
Engine Timing Sensor : Other Failure Mode The engine has failed the automatic timing calibration during engine start-up.
The code is logged.
The value of the timing offset that has been stored in memory will be used. This value will continue to be used for the timing calibration until the diagnostic is resolved.
723-8
Engine Speed Sensor #2 : Abnormal Frequency, Pulse Width, or Period The code is latched in the active state until the power to the Electronic Control Module (ECM) is cycled.
The offset for the timing calibration is set to zero when the diagnostic code is active.
The sensor is ignored. The engine speed is calculated by using only the signal from the primary speed/timing sensor. The Electronic Control Module (ECM) provides the engine speed/timing sensor with a regulated voltage of 8.0 0.5 VDC. The engine speed/timing sensor provides a pulse signal to the ECM. The signal is created as the timing reference gear rotates past the pickup of the engine speed/timing sensor. The timing reference gear is mounted on the rear of the left camshaft. A unique tooth pattern on the timing reference gear allows the ECM to determine the crankshaft position, rotation, and rpm.The engine speed/timing sensor generates a pulse signal to the ECM as each tooth passes the sensor. The ECM counts the pulses to determine the engine rpm. The ECM memorizes the pattern of the pulses. The ECM compares that pattern to a standard pattern to determine the crankshaft position. The ECM uses this information to determine the position of the No. 1 cylinder. The ECM will use the engine speed/timing signals to determine when to fire the spark plugs to begin ignition. The loss of a signal from an engine speed/timing sensor generates a diagnostic code. If the signal from both the primary engine speed/timing sensor and the secondary engine speed/timing sensor are lost, the ECM will terminate ignition.Under normal operation, the ECM utilizes the signal from the primary speed/timing sensor to determine the crankshaft position for an accurate fuel delivery and timing. This feature eliminates the need for a separate procedure for timing calibration. A timing offset is determined during each engine start-up. The value of the timing offset is stored in the non-volatile memory of the ECM until the successful completion of the next engine start-up. If a failure mode for the primary engine speed/timing sensor is detected during engine start-up, timing calibration is aborted. The value of the timing offset stored in ECM memory will be used. This value will continue to be used for the engine timing calibration until the diagnostic is resolved. A timing calibration cannot be performed manually on this engine.
Illustration 1 g06487031
For the complete circuit details, refer to the full schematic.
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect the Cat® Electronic Technician (Cat ET) Service Tool to the service tool connector.
B. Start the engine.
C. Run the engine until normal operating temperature is reached.
Note: If the engine will not start, monitor the engine rpm on Cat ET when the engine is being cranked. If necessary, power Cat ET from another battery when the engine is being cranked.
D. Look for these codes and pattern status parameters on Cat ET:
Codes:
- 190–08
- 723–08
- 637-11
Parameters:
- "Primary Engine Speed Sensor Timing Pattern Status"
- "Secondary Engine Speed Sensor Timing Pattern Status"
Note: When checking status parameters, engine must be in a cranking state.
Note: Valid engine speed may be shown without a pattern being locked.
Codes
Result: None of the diagnostic codes that are listed above are active or logged and the primary/secondary speed sensor timing status is "OK". The engine is not running properly.
Repair: Refer to the appropriate engine symptom in this Troubleshooting Manual.
Result: A 190-08, 637-11, or a 723-08 code is active or logged or primary/secondary speed sensor timing status is "Not OK".
Proceed to Test Step 2.
Result: At least one of the following is true:
- Cat ET is not reporting engine rpm for at least one engine speed/timing sensor while the engine is cranked
- At least one of the speed timing pattern status parameters are displayed as "Not OK"
Proceed to Test Step 3.
2. Check the Installation of the Sensor Assembly
A. Turn the main disconnect switch to the OFF position.
B. Visually inspect the sensors without removing the sensor assembly from the engine.
Verify that the bracket securely holds the flange of the sensor flush against the mounting surface.
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 suspect engine speed/timing sensor from the engine.
D. Ensure that the O-ring seals are installed and free of damage.
Sensor
Result: The O-ring seals are properly installed. The bracket and the seals are free of damage.
Repair: Perform the following procedure:
1. Lubricate the O-ring seals with oil.
2. Fully seat the sensor into the housing.
Note: If the sensor assembly will not fully seat into the engine, replace the sensor assembly.
3. Tighten the bolts.
4. Connect the connector.
5. Ensure that the harness is properly secured, and that the tie-wraps are placed in the correct location.
Proceed to Test Step 3.
Result: At least one of the sensor assembly components is NOT OK.
Repair: Install a new sensor assembly.
If the problem is not resolved, proceed to Test Step 3.
3. Inspect the Electrical Connectors and the Wiring
A. Turn the main disconnect switch to the OFF position.
B. Thoroughly inspect the connectors. Refer to Troubleshooting, "Electrical Connectors-Inspect" for additional information.
C. Perform a 45 N (10 lb) pull test on the connector wires.
D. Check the harness for abrasions and pinch points.
Connectors and Wiring
Result: The connectors and wiring appear to be OK.
Proceed to Test Step 4.
Result: There is a problem with the connectors and/or wiring.
Repair: Repair or replace the connectors or wiring. Ensure that all the seals are properly in