17615 18 Mercury SPACER SHIM .214"

Table 1
Diagnostic Trouble Codes for the Engine Speed/Timing Sensors    
J1939 Code    Description    Notes    
190-8     Engine Speed : Abnormal Frequency, Pulse Width, or Period     The Electronic Control Module (ECM) detects the following conditions:
An intermittent loss of signal or a complete loss of signal from the primary speed/timing sensor for 2 seconds
The engine has been running for more than 3 seconds.
Diagnostic trouble code 168-4 is not active.
678 diagnostic trouble codes are not active.
If equipped, the warning light will come on and the diagnostic code will be logged.
The ECM will use the signal from the secondary speed/timing sensor.
The engine will be derated. If the signal from the secondary speed/timing sensor is also lost, the engine will shut down.    
723-8     Engine Speed Sensor #2 : Abnormal Frequency, Pulse Width or Period     The Electronic Control Module (ECM) detects the following conditions:
A loss of signal from the secondary speed/timing sensor for 2 seconds while the signal from the primary speed/timing sensor remained valid
The engine has been running for more than 3 seconds.
Diagnostic trouble code 168-4 is not active.
678 diagnostic trouble codes are not active.
If equipped, the warning lamp will come on and the diagnostic code will be logged.
The loss of signal from the secondary speed/timing sensor will prevent the engine from starting.    
637-11     Engine Timing Sensor : Other Failure Mode     The Electronic Control Module (ECM) detects the following conditions:
The outputs from the primary speed/timing sensor and the secondary speed/timing sensor differ by more than 8 crankshaft degrees.
The engine has been running for more than 5 seconds.
Diagnostic code 190-8 is not active.
678 diagnostic codes are not active.
If equipped, the warning light will come on. This code will not be logged.    
678-3     ECU 8 Volts DC Supply : Voltage Above Normal     The Electronic Control Module (ECM) detects the following conditions:
The 8 VDC supply is more than 8.6 VDC for more than one second
The engine has been powered for more than 3 seconds.
Diagnostic code 168-3 is not active.
The ECM will log the diagnostic code and the code will be displayed on the operator console.    
678-4     ECU 8 Volts DC Supply : Voltage Below Normal     The Electronic Control Module (ECM) detects the following conditions:
The 8 VDC supply is less than 7.2 VDC for more than one second
The engine has been powered for more than 3 seconds.
Diagnostic code 168-4 is not active.
The ECM will log the diagnostic code and the code will be displayed on the operator console.    Use this procedure when the engine will not start and the electronic service tool indicates a faulty sensor by displaying "Not Detected" against the faulty sensor on the "No Start Parameter" screen.The engine uses two engine speed/timing sensors. The primary speed/timing sensor is located on the left-hand side of the cylinder block close to the flywheel housing. 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 on the right-hand side of the cylinder block toward the rear of the engine. 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 teeth on the timing ring for 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. The engine will stop.The primary sensor and the secondary sensor are interchangeable components. If a sensor is suspect, the sensors can be exchanged in order to eliminate a fault. If a secondary sensor is suspect and a replacement secondary sensor is not available, then the primary sensor and the secondary sensor can be exchanged. This exchange will allow testing to determine if the secondary sensor is faulty.
Illustration 1 g01878676
Schematic for the speed/timing sensors
Illustration 2 g01980993
View of the pin locations for the speed/timing sensor on the P2 connector (44) Supply for the speed/timing sensor (8 VDC) (38) Signal for the primary speed/timing sensor (39) Signal for the secondary speed/timing sensor
Illustration 3 g02474338
View of the sensor locations (1) Primary speed/timing sensor (2) Secondary speed/timing sensor
Illustration 4 g01212995
Typical example of a speed/timing sensor (1) 8 VDC Supply (2) SignalTest Step 1. Inspect the Electrical Connectors and the Harness
Turn the keyswitch to the OFF position.
Inspect the connectors for the speed/timing sensors. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Perform a 45 N (10 lb) pull test on each of the wires in the suspect sensor connector and the sensor connections at the ECM.
Check that the ground connection on the ECM and the negative terminal on the battery are correctly installed.
Check the ground connection on the ECM for abrasions and pinch points.
Check the screws for the ECM connector for the correct torque of 6 N m (53 lb in).
Check the harness for abrasion and pinch points from the suspect sensor to the ECM.
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.Expected Result:The electrical connectors and