90741-ZY3-000 Honda KEY, SPECIAL (Honda Code 6994370).

Table 1
Diagnostic Trouble Codes for the Speed/Timing Sensors
J1939 Code Code 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 shut down only if the signals from the primary engine speed/timing sensor and the secondary engine speed/timing sensor are abnormal.
723-8 Engine Speed Sensor #2 : 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 shut down only if the signals from the primary engine speed/timing sensor and the secondary engine speed/timing sensor are abnormal.
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 degrees of crankshaft rotation.
The engine has been running for more than 5 seconds.
The warning light will come on. This code will not be logged.
Illustration 1 g06498452
Table 2
Troubleshooting Test Steps Values Results
1. Check the Engine Speed/Timing Circuit
A. Connect the electronic service tool to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
B. Turn the keyswitch to ON.
C. Start the engine and run the engine.
Note: 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 2.
Result: The engine did not start.
Proceed to Test Step 3.
2. Check for Codes
A. While the engine is running, monitor the electronic service tool for diagnostic 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 the electronic service tool:
• 190-8
• 723-8
•637–11
Codes
Result: Diagnostic code 637–11 is active.
Proceed to Test Step 3.
Result: Diagnostic code 190–8 or 723–8 is active or there is a timing pattern that is "Not Detected".
Proceed to Test Step 4.
Result: There is not an active diagnostic code and there is not a timing pattern that is "Not Detected".
Repair: Download the "Product Status Report" (PSR) from the engine ECM. Troubleshoot any diagnostic codes that may be present.
Return the unit to service.
3. Inspect the Sensors
A. Ensure that the speed/timing sensors are correctly seated in the flywheel housing and the cylinder block and that the retaining bolts are tightened to a torque of 22 N m (16 lb ft). Ensure that the speed/timing sensors are not damaged.
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".
B. Turn the keyswitch to the ON position. If the engine will run, then run the engine.
C. Use the electronic service tool to check if the 637-11 diagnostic code is still active.
Faulty sensor
Result: A 637-11 diagnostic code is no longer active.
Use the electronic service tool to clear all logged diagnostic codes. Return the engine to service.
Result: A 637-11 diagnostic code is still active.
Repair: If the engine has been reworked before the active 637-11 diagnostic code occurred, ensure that the flywheel and the camshaft gear have been aligned correctly.
If the fault is still present, contact the Dealer Solutions Network (DSN).
4. Check the Battery Voltage
A. Monitor the "Engine Starting" screen in the electronic service tool.
B. Monitor the "Battery Voltage". Crank the engine for 5 seconds.
Battery Voltage
Result: The battery voltage is OK.
Proceed to Test Step 5.
Result: The battery voltage is not OK.
Repair: Refer to Troubleshooting, "Engine Cranks but Does Not Start".
5. Check the Engine Speed and the Engine Speed/Timing Status
A. Monitor the "Engine Starting" screen in the electronic service tool.
B. Crank the engine for 5 seconds. While the engine is cranking, verify that the sensors show an acceptable cranking speed.
C. While the engine is cranking, check the status of the engine speed/timing.
Speed/Timing Status
Result: The sensors show an acceptable cranking speed. The timing pattern shows "Detected".
Repair: Refer to Troubleshooting, "Engine Cranks but Does Not Start".
Result: A sensor does not show an acceptable cranking speed and/or the timing pattern shows "Not Detected".
Proceed to Test Step 6.
6. Check the Speed/Timing Sensor
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 timing gear housing and the flywheel housing to ensure proper operation.
C. 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.
Speed/Timing Sensor
Result: The sensor and the sensor assembly mounting are OK. Do not reconnect the harness connector.
Proceed to Test Step 7.
Result: The sensor and/or the sensor assembly has a mechanical problem or the harness has debris and/or corrosion.
Repair: Repair the sensor and/or the sensor assembly or replace the sensor and/or the sensor assembly. Replace the sensor and the sensor harness connector if there was debris and/or corrosion.
Verify that the problem is resolved.
7. Use a Multimeter to Check the Harness Wiring at the Sensor Connector
A. Disconnect the affected speed/timing sensor from the wiring harness.
B. Turn the keyswitch to ON.
C. Perform substeps D-E for the affected sensor.
D. Measure the voltage between terminal 3 (5V SUPPLY) and terminal 2 (RETURN). The voltage should be 5V +/-.2V.
E. Measure the voltage between terminal 1 (SIGNAL) and terminal 2 (RETURN). The voltage should be 4.8V +/- 0.3V.
Check Wiring Harness
Result: The voltage was OK for all the measurements.
Repair: Replace the affected speed/timing sensor.
Result: The voltage was not OK for at least one of the measurements.
Proceed to Test Step 8.
8. Use a Multimeter to Check the Harness Wiring at the Engine Interface Connector
A. Disconnect the engine interface connector.
B. Turn the keyswitch to ON.
C. Perform substeps D-E for the affected sensor.
D. Measure the voltage between the 5V supply terminal and