RING-EXPANDER 1921422 - Caterpillar

Illustration 1 g02157746
Retarder lever position sensor circuitThis diagnostic code is associated with the retarder lever position sensor. The FMI 08 means that the ECM has determined that the signal frequency or the signal pulse width is not within the expected range. The retarder lever position sensors are PWM sensors. A fully rearward lever position is represented by a 10% duty cycle. A fully forward lever position is represented by a 90% duty cycle. The ECM measures the duty cycle of the signal. The possible causes of this diagnostic code are listed below:
The sensor has failed.
Intermittent connections or poor connections
Mechanical devices are loose.
The ECM has failed. ECM failure is unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 1227 FMI 08 is active before performing this procedure.Note: Use a calibrated 146-4080 Digital Multimeter for the measurements in this procedure. Test Step 1. CHECK FOR POWER AT THE SENSOR.
Do not disconnect the harness connector from the sensor.
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the voltage supply wire (contact 1).
Turn the keyswitch and the disconnect switch to the ON position.
Measure the voltage from contact 1 to frame ground.Expected Result:The voltage is 24 DCV.Results:
OK - The voltage is 24 DCV. Proceed to Test Step 3.
NOT OK - The voltage is not 24 DCV. The circuit is open. Repair: Repair or replace the machine harness.STOPTest Step 2. CHECK THE SIGNAL CIRCUIT OF THE SENSOR.
Turn the keyswitch and the disconnect switch to the OFF position.
At the back of the harness connector for the sensor perform the following actions: and
Remove the 7X-1710 Multimeter Probe from contact 1
Insert the probe along the signal wire (contact 3).
At the back of the harness connector for the sensor, insert the 7X-1710 Multimeter Probe along the ground wire (contact 2).
Turn the disconnect switch and the keyswitch to the ON position.
Monitor the signal of the