SETSCREW 2726174 - Caterpillar

Illustration 1 g01551913
Schematic of the "Low Idle" SwitchThis diagnostic code is associated with the "Low Idle" Switch. This switch has two inputs to the ECM: normally open (wire K974-PU) and normally closed (wire K973-PK). During normal operation, one switch input is open and the other input is grounded. If each input is in the same state, the ECM will detect a diagnostic code. This diagnostic code is detected when both switch inputs are open at the same time.The possible causes of this diagnostic code are listed:
Short to the ground circuit.
The circuit is shorted.
A failed switch
The ECM may have failed. This is unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 2977 FMI 04 is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.Test Step 1. CHECK THE CIRCUIT FOR THE SWITCH.
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the J2 engine harness connector from the Engine ECM.
At the J2 engine harness connector, measure the resistance from contact J2-39 (wire K973-PK) to contact J2-35 (wire K975-WH) with the switch in the Enabled position and the Disable positions.
At the J2 engine harness connector, measure the resistance from contact J2-52 (wire K974-PU) to contact J2-35 (wire K975-WH) with the switch in the Disabled position and the Enabled position.Expected Result:The resistance should measure between approximately 5 ohms, in one position, and greater than 5000 ohms, in the opposite position, for each position of the switch.