C13 Engines for Caterpillar Built Machines Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with the primary engine speed/timing sensor. Also use this procedure if a problem is suspected with the secondary engine speed/timing sensor. Use this procedure to troubleshoot the electrical system if a diagnostic code in Table 1 is active or easily repeated.

Table 1

Diagnostic Trouble Codes
CDL Code and Description	Comments
190-8 Engine Speed Sensor : Abnormal Frequency, Pulse Width, or Period	The code is logged. The Electronic Control Module (ECM) can default to the secondary engine speed/timing sensor. The default will occur if a valid signal is not received from the primary engine speed/timing sensor. The engine will shutdown only if the signals from the primary engine speed/timing sensor and the secondary engine speed/timing sensor are abnormal.
342-8 Secondary Engine Speed Sensor : Abnormal Frequency, Pulse Width, or Period	The code is logged. If a valid signal is not received from the secondary engine speed/timing sensor, the ECM will default to the primary engine speed/timing sensor. The engine will shutdown only if the signals from the primary engine speed/timing sensor and the secondary engine speed/timing sensor are abnormal.

Illustration 1	g01199875

Probable Causes

• Codes

• Speed/Timing circuit

• Battery voltage

• Cranking speed

• Sensor

• Sensor supply voltage

• Resistance

Recommended Actions

Table 2

Troubleshooting Test Steps	Values	Results
1. Check for Codes A. While the engine is running, monitor Cat® Electronic Technician (ET) for codes. Also monitor the "Engine Starting" screen for an engine speed/timing that is "Not Detected". B. Wait at least 30 seconds for activation of the diagnostic codes. Look for these codes on Cat ET: 190-8 342-8	Codes	Result: There is an active diagnostic code or there is a timing pattern that is "Not Detected". Proceed to Test Step 5. Result: There is not an active diagnostic code and there is not a timing pattern that is "Not Detected". Repair: Download the "Warranty Report" from the engine ECM. Troubleshoot any diagnostic codes that may be present. If the problem is not resolved, proceed to Test Step 2.
2. Check the Engine Speed/Timing Circuit A. Establish communication between Cat ET and the ECM . B. Turn the keyswitch to ON. C. Monitor the "Engine Starting" screen in Cat ET. D. Start the engine and run the engine. The problem may occur when the engine is at any operating temperature. However, the problem is more likely to occur when the engine is at the normal operating temperature.	Speed/Timing circuit	Result: The engine started. Proceed to Test Step 4. Result: The engine did not start. Proceed to Test Step 3.
3. Check the Battery Voltage A. Monitor the "Engine Starting" screen in Cat ET. B. Monitor the battery voltage. Crank the engine for 5 seconds. C. Monitor the battery voltage while cranking.	Battery voltage	Result: The battery voltage is OK. Proceed to Test Step 4. Result: The battery voltage is NOT OK. Repair: Refer to Troubleshooting, "Engine Cranks but Does Not Start". If the problem is not resolved, proceed to Test Step 4.
4. Check the Engine Speed and the Engine Speed/Timing Status A. Monitor the "Engine Starting" screen in Cat ET. B. Crank the engine for 5 seconds. Verify that the sensors show an acceptable cranking speed. C. While the engine is cranking, check the status of the engine speed/timing sensors.	Cranking speed	Result: A sensor is NOT OK. The timing pattern shows "Not Detected". Proceed to Test Step 5. Result: The sensors are OK. The timing pattern shows "Detected". Repair: Refer to Troubleshooting, "Engine Cranks but Does Not Start". If the problem is not resolved, proceed to Test Step 5.
5. Inspect the Sensor Assembly A. Turn the keyswitch to OFF. B. Visually inspect the sensor and the sensor assembly without removing the sensor assembly from the engine. Flanges must be flush against the surface of the front timing gear housing to ensure proper operation. C. Inspect the sensor bracket . Verify that the bracket securely holds the flanges of the sensors flush against the engine. D. Verify that the bracket is not bent. If the bracket is bent or if an obstruction is preventing the sensor assembly from being installed correctly, the engine will not start. E. Disconnect the harness from the speed/timing sensors. Check the harness for debris and for corrosion. F. Perform a 45 N (10 lb) pull test on the harness wiring.	Sensors	Result: The sensor and the sensor assembly mounting are OK. Proceed to Test Step 6. Result: The sensor and/or the sensor assembly are NOT OK. Repair: Repair the sensor and/or the sensor assembly or replace the sensor and/or the sensor assembly. If the problem is not resolved, proceed to Test Step 6.
6. Use a Multimeter to Check the Harness Wiring A. Turn the keyswitch to ON. B. Perform the following procedure for each sensor. The voltage is 2.4 ± 0.2 VDC. 1. Measure the voltage between terminal 1 and a good engine ground. 2. Measure the voltage between terminal 2 and a good engine ground.	Voltage	Result: The voltage is OK. Proceed to Test Step 7. Result: The voltage is NOT OK. There is a problem in the harness wiring. Repair: Repair the appropriate harness wiring or replace the appropriate harness. If the problem is not resolved, proceed to Test Step 7.
7. Measure the Resistance of the Sensor A. Turn the keyswitch to OFF. B. Disconnect the engine harness from the sensor. C. Remove the sensor. Check the sensor tip for any damage. D. For the primary engine speed/timing sensor, measure the resistance between terminal 2 to terminal 1. Resistance values should be 75Ω to 230Ω. E. For the secondary engine speed/timing sensor, measure the resistance between terminal 2 to terminal 1. Resistance values should be 600Ω to 1800Ω. F. Turn the keyswitch to ON. G. Check for -13 codes. Wait at least 30 seconds in order for the diagnostic codes to become active.	Resistance	Result: The resistance is OK. Repair: If the engine was running before removing the sensor, reinstall the sensor. Use Cat ET to check for any active diagnostic codes. Troubleshoot any active diagnostic codes. If the engine was not running before removing the sensor, refer to Troubleshooting, "Engine Cranks but Does Not Start". Result: The resistance is NOT OK. There is damage to the sensor tip. Repair: Inspect the housing for a cause of the sensor damage. Make any necessary repairs. Replace the sensor assembly.

If the problem is not resolved, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).