ROD AS 3G7603 - Caterpillar

Table 1
J1939 Code and Description CDL Code and Description Comments
190-2
Engine Speed : Erratic, Intermittent, or Incorrect 190-2
Engine Speed Sensor : Erratic, Intermittent, or Incorrect An abnormal signal from the primary speed/timing sensor has been detected. If a valid signal is not received from the primary engine speed/timing sensor, the Electronic Control Module (ECM) will default to the secondary 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.
The code is logged.
190-8
Engine Speed Sensor : Abnormal Frequency, Pulse Width, or Period 190-8
Engine Speed Sensor : Abnormal Frequency, Pulse Width, or Period The 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.
The code is logged.
723-2
Engine Speed Sensor #2 : Erratic, Intermittent, or Incorrect 342-2
Secondary Engine Speed Sensor : Erratic, Intermittent, or Incorrect An abnormal signal from the secondary speed/timing sensor has been detected.
The code is logged.
723-8
Secondary Engine Speed Sensor : Abnormal Frequency, Pulse Width, or Period 342-8
Secondary Engine Speed Sensor : Abnormal Frequency, Pulse Width, or Period 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.
The code is logged. The Electronic Control Module (ECM), Gas Actuation Valve (GAV) ECM, and In Cylinder Pressure Sensor (ICPS) ECM uses the pattern of the pulses from the speed/timing sensors to determine the position of the crankshaft and camshaft. The ECM measures the time between the pulses that are created by the sensors as the gears rotate to determine rpm.After locating the No. 1 cylinder, the ECM triggers each injector in the correct firing order and at the correct unit injector timing. The actual timing and duration of each injection is based on engine rpm and load.Pay close attention to which ECM is reporting the speed timing fault. The Engine ECM, ICPS ECM, and GAV ECM can all report loss of speed timing signals. A problem with the speed timing sensor or timing pattern should result in all ECM's reporting a speed timing fault. A problem with the wiring or connections is more likely if less than all ECMs are reporting the speed timing error.
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET).
B. Determine if a code is active or logged.
Codes
Result: A -2 or -8 code is active or logged.
Proceed