0777171 JOHNSON White

Table 1
Diagnostic Codes Table    
Code and Description     Conditions which Generate this Code     System Response    
190-2 Engine Speed Sensor erratic, intermittent, or incorrect     The signal from the primary engine speed/timing sensor has been lost.
The code is logged only if the engine has been running for three seconds.     The code is logged.
If a valid signal is not received from the primary engine speed/timing sensor, the Electronic Control Module (ECM) will default to the secondary engine speed/timing sensor. The engine will shut down only if the signals from the primary engine speed/timing sensor and the secondary engine speed/timing sensor are abnormal.
The injector solenoids may fire erratically.    
190-3 Engine Speed Sensor voltage above normal     The supply voltage for the primary engine speed/timing sensor is above normal.    
190-8 Engine Speed Sensor abnormal frequency, pulse width, or period     The signal from the primary engine speed/timing sensor has been incorrect for at least five seconds.    
342-2 Secondary Engine Speed Sensor erratic, intermittent, or incorrect     The signal from the secondary engine speed/timing sensor has been lost.
The code is logged only if the engine has been running for three seconds.     The code is logged.
The engine will shut down only if the signals from the primary engine speed/timing sensor and the secondary engine speed/timing sensor are abnormal.
The injector solenoids may fire erratically.    
342-3 Secondary Engine Speed Sensor voltage above normal     The supply voltage for the secondary engine speed/timing sensor is above normal.    
342-8 Secondary Engine Speed Sensor abnormal frequency, pulse width, or period     The signal from the secondary engine speed/timing sensor has been incorrect for at least five seconds.    The engine uses two engine speed/timing sensors. Both sensors detect the reference for engine speed and timing from a timing reference ring with a unique pattern that is on the rear face of the fuel injection pump gear. The ECM uses the pattern of the pulses in order to determine the position of the crankshaft. The ECM measures the time between the pulses that are created by the sensors as the gears rotate in order to determine rpm.Under normal operation, the primary speed/timing sensor determines when the piston in the number 1cylinder is at the top of the compression stroke. When the timing has been established, the sensor signal is used to determine engine speed.When the timing has been established, the ECM triggers each injector in the correct firing order at the correct time. The actual timing and duration of each injection is based on engine rpm and on load. The secondary speed/timing sensor provides continuous operation of the engine if the primary engine speed/timing sensor fails. If the engine is running and the signal from one sensor is lost, no change in engine performance will be noticed. If the engine is running and the signals from both sensors are lost, fuel injection will be terminated and the engine will be shut down by the ECM. The engine will start when only one sensor signal is present. The engine will not start if the signals from both sensors are lost.The engine speed/timing sensors receive supply voltage from the ECM that is regulated at 12.5 1.0 VDC. The engine speed/timing sensors provide a pulsed DC output voltage with a frequency that is directly proportional to engine speed. A unique tooth on the timing reference ring generates a duty cycle in order to provide the ECM with information on the crankshaft position.
Illustration 1 g01854336
Schematic for the engine speed/timing sensorsTest Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
Illustration 2 g01139425
ECM (1) J1/P1 connectors (2) J2/P2 connectors
Thoroughly inspect the J1/P1 ECM connector and the J2/P2 ECM connector. Inspect all of the connectors that are associated with the circuit.Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 3 g01823953
P1 ECM connector (P1-29) Digital return (P1-32) Speed/timing sensor supply (P1-38) Primary speed/timing sensor signal (P1-39) Secondary speed/timing sensor signal (P1-18) TDC probe + (P1-12) TDC probe -
Perform a 45 N (10 lb) pull test on each of the wires in the circuit.
Check the allen head screw from each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque value.
Check the harness and the wiring for abrasion and for pinch points.Expected Result:All of the connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The harness and connectors appear to be OK. Proceed to Test Step 2.
Not OK - The connectors and/or wiring are not OK.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. 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.STOPTest Step 2. Check for Diagnostic Codes
Connect the Cat ET to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Restore electrical power to the ECM.
Check for active diagnostic codes on Cat ET.Look for the following codes:
190-02
190-03
190-08
342-02
342-03
342-08Expected Result:None of the above diagnostic codes are active.Results:
OK - None of the above codes are active, but there is a problem that has been associated with the engine speed/timing sensors. Proceed to Test Step 3.
OK - None of the above codes are active.Repair: There may be an intermittent problem in the circuit. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - One or more of the above codes are active. Proceed to Test Step 3.Test Step 3. Inspect the Condition of the Engine Speed/Timing Sensors
Remove electrical power from the ECM.
Remove the suspect engine speed/timing sensor.
Inspect the sensor tip for damage.
Inspect the plastic slip head for damage.
Check the tension on the slip head by gently prying the slip head out of the sensor body. Extend the slip head 3 to 4 mm (0.12 to 0.16 inch). Push the slip head back into the sensor body from the extended position. Movement of the slip head will require a small amount of