955886 Volvo.Penta Castle nut

The engine uses two engine speed/timing sensors. The primary speed/timing sensor is located on the front left-hand side of the cylinder block. The primary speed/timing sensor generates a signal by detecting the movement of the teeth that are located on the crankshaft timing ring. The signal that is generated by the speed/timing sensor is transmitted to the ECM. The ECM uses the signal from the speed/timing sensor to calculate the position of the crankshaft. The signal is also used to determine the engine speed.The secondary speed/timing sensor is located in the front cover. The secondary speed/timing sensor generates a signal that is related to the camshaft position. The secondary speed/timing sensor detects the movement of the position wheel on the front of the camshaft. The signal that is generated by the speed/timing sensor is transmitted to the ECM. The ECM calculates the speed and the rotational position of the engine by using the signal. The secondary speed/timing sensor is required for starting purposes.During normal operation, the secondary speed/timing sensor is used to determine the cycle that the engine is on. When the timing has been established, the primary speed/timing sensor is then used to determine the engine speed and the angular position.The loss of signal to the primary sensor and/or the secondary sensor will result in one of the following faults:
The engine will continue to run when only one sensor signal is present from either the primary sensor or the secondary sensor.
Loss of signal from the primary sensor and the secondary sensor during operation of the engine will cause fuel injection to be terminated and the engine will stop.Pull-up VoltageThe ECM continuously outputs a pull-up voltage on the circuit for the secondary speed/timing sensor signal wire. This pull-up voltage is required for correct sensor operation and diagnostics.When the sensor is disconnected, this pull-up voltage can be measured at the harness connector for the sensor.
Illustration 1 g06555153
Schematic diagram for the engine speed/timing sensors
Not all connectors are shown. Refer to the appropriate Electrical Schematic.
Illustration 2 g02648462
View of the pin locations for the speed/timing sensors on the P2 connector
(13) Secondary speed/timing sensor 5 V supply
(14) Secondary speed/timing sensor signal
(28) Secondary speed/timing sensor ground
(44) Primary speed/timing sensor return
(58) Shield
(59) Primary speed/timing sensor supply
Illustration 3 g02648476
View of the sensor locations
(1) Primary speed/timing sensor
(2) Secondary speed/timing sensor
Illustration 4 g02648517
Typical example of the secondary speed/timing sensor
(1) Secondary speed/timing sensor ground
(2) Secondary speed/timing sensor signal
(3) Secondary speed timing sensor 5 V supply
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Turn the keyswitch to the OFF position.
B. Inspect the connectors for the speed/timing sensors. Refer to Troubleshooting, "Electrical Connectors - Inspect".
C. Perform a 30 N (6.7 lb) pull test on each of the wires in the suspect sensor connector and the sensor connections at the ECM.
D. Check that the ground connection on the ECM and the negative terminal on the battery are correctly installed.
E. Check the ground connection on the ECM for abrasions and pinch points.
F. Check the harness for abrasion and pinch points from the suspect sensor to the ECM.
G. Check that the suspect sensor is installed correctly. Check that the suspect sensor is fully seated into the engine. Check that the sensor is securely latched.
Damaged wire or connector
Result: A damaged wire or damaged connector was found.
Repair the damaged wire or the damaged connector.
Use the electronic service tool to clear all logged diagnostic codes. Verify that the repair eliminates the fault.
Result: All connectors, pins, and sockets are correctly connected and/or inserted and the harness is free of corrosion, of abrasion or of pinch points.
Proceed to Test Step 2.
2. Check for Active Diagnostic Codes and Recently Logged Diagnostic Codes
A. Turn the keyswitch to the OFF position.
B. Connect the electronic service tool to the diagnostic connector.
C. Turn the keyswitch to the ON position. If the engine will start, then run the engine.
D. Use the electronic service tool in order to monitor active diagnostic codes or recently logged diagnostic codes.
Diagnostic codes
Result: Diagnostic code 190-8 is active or recently logged.
Proceed to Test Step 3.
Result: Diagnostic code 723-8 is active or recently logged.
Proceed to Test Step 5.
Result: Diagnostic code 637-11 is active or recently logged.
Proceed to Test Step 8.
3. Measure the Signal Frequency at the Sensor Connector
A. Turn the keyswitch to the OFF position.
B. Disconnect the primary speed/timing sensor.
Note: A multimeter that can measure frequency (Hz) is required for this procedure.
C. Connect the multimeter to pin 1 and pin 2 on the sensor connector.
D. Turn the keyswitch to the START position.
E. Record the frequency while the engine is cranking.
At least 100 Hz.
Result: The measured frequency is