24321-ZY3-620 Honda ROD A, SHIFT (XXL) (Honda Code 6991251).

Table 1
Diagnostic Trouble Codes
J1939 Code CDL Code Code Description
(code descriptions may vary) Comments
190-8 190-8 Engine Speed : Abnormal Frequency, Pulse Width, or Period The Electronic Control Module (ECM) detects the following conditions:
An intermittent loss of signal or a complete loss of signal from the primary speed/timing sensor for 2 seconds
The engine has been running for more than 3 seconds.
678 diagnostic trouble codes are not active.
If equipped, the warning light will come on and the diagnostic code will be logged.
The ECM will use the signal from the secondary speed/timing sensor.
The engine will be derated. If the signal from the secondary speed/timing sensor is also lost, the engine will shut down.
723-8 342-8 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 2 seconds while the signal from the primary speed/timing sensor remained valid
The engine has been running for more than 3 seconds.
678 diagnostic trouble codes are not active.
If equipped, the warning lamp will come on and the diagnostic code will be logged.
The loss of signal from the secondary speed/timing sensor will prevent the engine from starting.
637-11 261-11 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.
Diagnostic code 190-8 is not active.
678 diagnostic codes are not active.
If equipped, the warning light will come on. This code will not be logged.
Follow the troubleshooting procedure in order to identify the root cause of the fault. Use this procedure when the engine will not start and the electronic service tool indicates a faulty sensor by displaying "Not Detected" against the faulty sensor on the "No Start Parameter" screen.The engine uses two engine speed/timing sensors. The primary speed/timing sensor is located on the left-hand side of the cylinder block close to the flywheel housing. 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.C4.4 Engine: The secondary speed/timing sensor is located on the left-hand side of the cylinder block under the high-pressure fuel pump. 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 fuel pump drive gear. 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.C7.1 Engine: The secondary speed/timing sensor is located on the right-hand side of the cylinder block toward the rear of the engine. 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 teeth on the timing ring for 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 both sensors during operation of the engine will cause fuel injection to be terminated and the engine will stop.The primary sensor and the secondary sensor are interchangeable components. If a sensor is suspect, the sensors can be exchanged in order to eliminate a fault. If a secondary sensor is suspect and a replacement secondary sensor is not available, then the primary sensor and the secondary sensor can be exchanged. This exchange will allow testing to determine if the secondary sensor is faulty.
Illustration 1 g03393101
Schematic for the speed/timing sensors
Illustration 2 g03379909
Pin locations for the speed/timing sensor on the P2 connector
(10) Speed/timing sensor 8 VDC supply
(52) Primary speed/timing sensor signal
(53) Secondary speed/timing sensor signal
Illustration 3 g03379946
Typical example of a speed/timing sensor
(1) 8 VDC Supply
(2) Signal
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Turn