C3.4B Engines Caterpillar

Speed/Timing - Test

Usage:

CCS7 4B2

This procedure covers the following codes:

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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: A loss of signal from the primary speed/timing sensor for four camshaft revolutions. OR An invalid signal from the primary speed/timing sensor. The engine speed is at least 680 rpm. There is a valid signal from the secondary speed/timing sensor. The warning lamp will flash. 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 four crankshaft revolutions. OR An invalid signal from the secondary speed/timing sensor for four engine revolutions. The engine is running. The warning lamp will come on. 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 10 crankshaft degrees for at least four engine revolutions. The engine is running. There is a valid signal from the secondary speed/timing sensor. The warning lamp will come on.

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 Voltage

The 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.

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Illustration 1	g03733664
Schematic diagram for the engine speed/timing sensors

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Illustration 2	g03733665
View of the pin locations for the speed/timing sensors on the 62-pin connector (4) Secondary speed/timing sensor signal (8) Secondary speed/timing sensor ground (9) Primary speed/timing sensor supply (10) Primary speed/timing sensor return (11) Primary speed/timing sensor shield (12) Secondary speed/timing sensor 5 VDC supply

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Illustration 3	g03733666
View of the pin locations for the speed/timing sensors on the P2 connector (13) Secondary speed/timing sensor 5 VDC supply (14) Secondary speed/timing sensor signal (28) Secondary speed/timing sensor ground (44) Primary speed/timing sensor return (59) Primary speed/timing sensor supply

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Illustration 4	g02648476
View of the sensor locations (1) Primary speed/timing sensor (2) Secondary speed/timing sensor

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Illustration 5	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 VDC supply

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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. Inspect the 62-pin engine interface connector. Refer to Troubleshooting, "Electrical Connectors - Inspect". D. 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. E. Check that the ground connection on the ECM and the negative terminal on the battery are correctly installed. F. Check the ground connection on the ECM for abrasions and pinch points. G. Check the harness for abrasion and pinch points from the suspect sensor to the ECM. H. 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: 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 6. Result: Diagnostic code 637-11 is active or recently logged. Proceed to Test Step 10.
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 less than 100 Hz. Repair: Remove the primary speed/timing sensor. Refer to Disassembly and Assembly, "Crankshaft Position Sensor - Remove and Install". Inspect the primary speed/timing sensor for damage and/or debris. If the primary speed/timing sensor is free from damage and/or debris, install a new primary speed/timing sensor. Refer to Disassembly and Assembly, "Crankshaft Position Sensor - Remove and Install". Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault. If the primary speed/timing sensor is damaged and/or contaminated with debris, proceed to Test Step 10. Result: The measured frequency is greater than 100 Hz. Proceed to Test Step 4.
4. Check the Engine Wiring Harness A. Turn the keyswitch to the OFF position. B. Disconnect the primary speed/timing sensor. Disconnect the P2 ECM connector. C. Measure the resistance between pin 1 on the harness connector for the primary speed/timing sensor and P2:59. D. Measure the resistance between pin 2 on the harness connector for the primary speed/timing sensor and P2:44.	Less than 5 Ohms	Result: At least one of the resistance measurements is greater than 5 Ohms. The fault is in the wiring between the primary speed/timing sensor and the 62-pin connector. Repair: Replace the faulty wiring. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: Both resistance measurements are less than 5 Ohms. Proceed to Test Step 5.
5. Check the Harness Between the Engine and the ECM A. Turn the keyswitch to the OFF position. B. Disconnect the 62-pin engine interface connector. Disconnect the P2 ECM connector. Thoroughly inspect the P2/J2 connector. Refer to Troubleshooting, "Electrical Connectors - Inspect". C. Measure the resistance between pin 9 on the 62-pin connector on the harness between the engine and the ECM and P2:59. D. Measure the resistance between pin 10 on the 62-pin connector on the harness between the engine and the ECM and P2:44.	Less than 5 Ohms	Result: At least one of the resistance measurements is greater than 5 Ohms. The fault is in the harness between the 62-pin connector and the P2 connector. Repair: Replace the faulty wiring. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: Both resistance measurements are less than 5 Ohms. Contact the Dealer Solution Network (DSN).
6. Check the Sensor Supply Voltage at the Sensor Connector A. Turn the keyswitch to the OFF position. B. Disconnect the connector for the secondary speed/timing sensor. C. Turn the keyswitch to the ON position. Do not start the engine. D. Measure the voltage between pin 1 and pin 3 on the harness connector for the secondary speed/timing sensor. E. Turn the keyswitch to the OFF position. F. Reconnect the connector for the secondary speed/timing sensor.	4.9 V to 5.1 V	Result: The measured voltage is not within the expected range. Proceed to Test Step 7. Result: The measured voltage is within the expected range. Proceed to Test Step 8.
7. Check the Sensor Supply Voltage at the 62-Pin Connector A. Turn the keyswitch to the OFF position. B. Disconnect the 62-pin engine interface connector. C. Turn the keyswitch to the ON position. Do not attempt to start the engine. D. Measure the voltage between pin 8 and pin 12 on the 62-pin connector on the harness between the engine and the ECM. E. Turn the keyswitch to the OFF position. F. Reconnect the 62-pin engine interface connector.	4.9 V to 5.1 V	Result: The measured voltage is within the expected range. The fault is in the 5 VDC supply wire or the ground wire between the sensor and the 62-pin connector. Repair: Replace the faulty wiring. Start the engine. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: The measured voltage is not within the expected range. The fault is in the 5 VDC supply wire or the ground wire between the 62-pin connector and the P2 connector. Repair: Replace the faulty wiring. Start the engine. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
8. Check for Signal Voltage at the Sensor Connector A. Turn the keyswitch to the OFF position. B. Disconnect the connector for the secondary speed/timing sensor. C. Turn the keyswitch to the ON position. Do not attempt to start the engine. D. Measure the voltage between pin 1 and pin 2 on the harness connector for the secondary speed/timing sensor. E. Turn the keyswitch to the OFF position. F. Reconnect the secondary speed timing sensor.	4.52 to 4.72 V	Result: The measured voltage is within the expected range. Repair: Replace the secondary speed/timing sensor. Refer to Disassembly and Assembly, "Camshaft Position Sensor - Remove and Install" for the correct procedure. Start the engine. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: The measured voltage is not within the expected range. Proceed to Test Step 9.
9. Check the Sensor Signal Voltage at the 62-Pin Connector A. Turn the keyswitch to the OFF position. B. Disconnect the 62-pin engine interface connector. C. Turn the keyswitch to the ON position. Do not attempt to start the engine. D. Measure the voltage between pin 4 and pin 8 on the 62-pin connector on the harness between the engine and the ECM. E. Turn the keyswitch to the OFF position. F. Reconnect the 62-pin engine interface connector.	4.52 V to 4.72 V	Result: The measured voltage is within the expected range. The fault is in the sensor signal wire between pin 2 on the sensor connector and pin 4 on the 62-pin connector. Repair: Replace the faulty wiring. Start the engine. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: The measured voltage is not within the expected range. Proceed to Test Step 10.
10. Check the Sensor Signal Voltage at the ECM A. Turn the keyswitch to the OFF position. B. Disconnect the P2 connector. C. Turn the keyswitch to the ON position. Do not attempt to start the engine. D. Measure the voltage between J2:14 and J2:28 on the ECM. E. Turn the keyswitch to the OFF position. F. Reconnect the P2 connector.	4.52 to 4.72 V	Result: The measured voltage is within the expected range. The fault is in the sensor signal wire between pin 4 on the 62-pin connector and P2:14. Repair: Replace the faulty wiring. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: The measured voltage is not within the expected range. Contact the DSN.
11. Inspect the Sensors A. Ensure that the speed/timing sensors are correctly seated in the cylinder block and the front cover and that the retaining bolts are tightened to the correct torque. Refer to Disassembly and Assembly, "Crankshaft Position Sensor - Remove and Install" or refer to Disassembly and Assembly, "Camshaft Position Sensor - Remove and Install". Ensure that the speed/timing sensors are not damaged. B. Replace any damaged sensors. Refer to Disassembly and Assembly, "Crankshaft Position Sensor - Remove and Install" or refer to Disassembly and Assembly, "Camshaft Position Sensor - Remove and Install". C. Use the electronic service tool to check if the 637-11 diagnostic code is still active.	Diagnostic code	Result: A 637-11 diagnostic code is not active at this time. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: A 637-11 diagnostic code is still active at this time. Proceed to Test Step 12.
12. Check the Crankshaft Timing Ring and the Camshaft Position Wheel A. Inspect the crankshaft timing ring. Refer to Disassembly and Assembly, "Crankshaft Timing Ring - Remove and Install". B. Inspect the camshaft position wheel. Refer to Disassembly and Assembly, "Camshaft Gear - Remove and Install".	Defects	Result: Found fault with the crankshaft timing ring or the camshaft position wheel Repair: If necessary, replace the camshaft position wheel. Refer to Disassembly and Assembly, "Camshaft Gear - Remove and Install". If necessary, replace the crankshaft timing ring. Refer to Disassembly and Assembly, "Crankshaft Timing Ring - Remove and Install". Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair has eliminated the fault. Result: No faults found. Contact the DSN.