CYLINDER HEAD AS 1515242 - Caterpillar

Illustration 3 g02642802
Schematic for the secondary speed timing circuit
Illustration 4 g02726035
Terminal locations at the P1 ECM connector for the secondary speed/timing sensor
(P1-5) Digital return
Illustration 5 g02726033
Terminal locations at the P2 ECM connector for the secondary speed/timing sensor
(P2-29) 8 V supply
(P2-35) Secondary speed signal Test Step 1. Inspect Electrical Connectors and Wiring
Remove electrical power from the ECM.
Thoroughly inspect the J1/P1 and J2/P2 ECM connectors. Inspect all of the other connectors for the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the allen head screw on each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and the wiring for abrasion and for pinch points. Expected Result:All connectors, pins, and sockets are coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - The harness and connectors appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem with the connectors and/or wiring.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 coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check for an Active or Logged Diagnostic Code
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Restore electrical power to the ECM.
Check for the following diagnostic codes on Cat ET:
190-8
678-3
678-4Expected Result:No diagnostic codes are active or logged repeatedly.Results:
OK - A diagnostic code for the engine speed/timing sensor is not active or logged repeatedly.Repair: There does not appear to be an electrical problem with the secondary speed/timing sensor at this time. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - One of the diagnostic codes listed above for the engine speed/timing sensor is active or logged repeatedly. Proceed to Test Step 3.Test Step 3. Check the Supply Voltage to the Sensor
Disconnect the connector for the engine speed/timing sensor.
Restore electrical power to the ECM.
Measure the voltage between terminals A and B at the sensor connector. Expected Result:The supply voltage is 8.0 0.5 VDC.Results:
OK - The supply voltage is 8.0 0.5 VDC. Proceed to Test Step 4.
Not OK - The supply voltage is not 8.0 0.5 VDC. Proceed to Test Step 6.Test Step 4. Check the Signal Voltage at the Sensor
Remove electrical power from the ECM.
Remove the wire from terminal C of the sensor connector.
Restore electrical power to the ECM.
Measure the voltage between the signal wire and terminal B of the sensor connector. Crank the engine and measure the voltage between the sensor signal wire and terminal B.
Remove electrical power from the ECM.
Reconnect the signal wire. Expected Result:The voltage measures less than 3 VDC or more than 6.5 VDC when the ECM is powered and the engine is not cranking. While the engine is cranking, the voltage is between 2 VDC and 7