0397627 JOHNSON GEARSET

Table 1
J1939 Code and Description CDL Code and Description System Response
190-8
Engine Speed : Abnormal Frequency, Pulse Width, or Period 190-8
Engine Speed Sensor : Abnormal Frequency, Pulse Width, or Period The engine is running for more than three seconds.
The Electronic Control Module (ECM) detects an abnormal signal frequency.
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.
723-8
Engine Speed Sensor #2 : Abnormal Frequency, Pulse Width, or Period 342-8
Secondary Engine Speed Sensor : Abnormal Frequency, Pulse Width, or Period The engine is running for more than three seconds.
The ECM detects an abnormal signal frequency.
The code is latched in the active state until the power to the ECM is cycled.
The offset for the timing calibration is set to zero while 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.
4202-8
Engine Speed Sensor #3 : Abnormal Frequency, Pulse Width, or Period 2710-8
Engine Tertiary Speed Sensor : Abnormal Frequency, Pulse Width, or Period The engine is in run mode for more than three seconds.
The ECM detects an abnormal signal frequency.
The sensor is ignored. The engine speed is calculated by using only the signal from the primary speed/timing sensor. This engine is equipped with three engine speed/timing sensors. The primary speed/timing sensor is mounted inside the engine crankcase and toward the left rear section of the engine. This sensor utilizes the teeth of the rear gear group crankshaft gear to sense the engine speed and the crankshaft position.The secondary speed/timing sensor and the tertiary speed/timing sensor are on the top rear portion of the engine. Both of these sensors utilize the teeth of the camshaft gear on the rear gear group to sense the engine speed and the camshaft position. A single tooth for both of these gears has been partially removed to provide a timing reference for the ECM.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.The fuel delivery to the engine is synchronized by the signal from the secondary speed/timing sensor (RH). If a failure mode for the primary speed/timing sensor is detected, the ECM will use the signal from this sensor for fuel delivery and timing.For this application, the tertiary speed/timing sensor (LH) is provided as a backup for the secondary speed/timing sensor (RH). The signal from the tertiary sensor will be used if a failure of the secondary speed/timing sensor (RH) is detected. The ECM will use the tertiary sensor to provide the functionality of the failed sensor.Use Cat® Electronic Technician (ET) to view the status of the engine speed sensors.The signal from any two engine speed/timing sensors is necessary for the engine to be started. The signal from any single speed/timing sensor is necessary for the engine to run. The speed/timing sensors are not interchangeable. Do not attempt to switch the positions of the sensors.Complete all the following tasks when you are installing the speed/timing sensors:
Ensure that an O-ring is installed on each sensor.
If an O-ring is damaged or missing, replace the O-ring.
Lubricate the O-rings with oil prior to installation of the sensor.
Ensure that the sensor assembly is fully seated into the engine before tightening the bracket bolt.
Ensure that each electrical connector is securely latched.
Ensure that the harness is properly secured, and ensure that each tie-wrap is placed in the correct location.
Illustration 1 g02566440
Schematic for the engine speed/timing circuit to (control assembly output) if equipped with A4 ECM
Illustration 2 g02566316
Schematic for the engine speed/timing circuit (control assembly output) if equipped with A4 ECM
Illustration 3 g06325137
Schematic for the engine speed/timing circuit if equipped with A5 ECM
Table 2
Troubleshooting Test Steps Values Results
1. Check for Diagnostic Codes
A. Remove electrical power from the ECM.
B. Connect Cat ET to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
C. Restore electrical power to the ECM.
D. 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. If necessary, power Cat ET from another battery while the engine is being cranked.
E. Look for these codes on Cat ET:
- 190-08
- 342-08
- 2710-8
Codes
Results: None of the diagnostic codes that are listed above are active or logged.
Repair: Use Cat ET to ensure that the engine speed is detected from all the engine speed/timing sensors. If the diagnostic codes that are listed above are not active or logged, and the engine is not running properly, refer to the appropriate engine symptom in this Troubleshooting manual.
Results: 190-08, 342-08, or 2710-08 active or logged. here is a 190-08, 342-08, or 2710-08 that is active or logged.
Proceed to Test Step 2
Results: No engine rpm. - Cat ET is not reporting engine rpm for at least one engine speed/timing sensor while the engine is cranked.
Proceed to Test Step 3
Illustration 4 g01279225
Sensor installation
(1) Flange
(2) Mounting surface
(3) Bracket