SWITCH-TEMPERATURE 2641420 - Caterpillar

Illustration 1 g00803362
Schematic of the Solenoid Valve (Air Start)
This diagnostic code is recorded when the ECM reads the current of the solenoid circuit as being below normal range (open circuit).Possible causes of this diagnostic code are listed:
Wire 306-GN(Green) is open.
The solenoid has failed.
The ECM has failed.Note: This procedure can cause new diagnostic codes to be recorded. Ignore these created diagnostic codes. Complete the following procedure. Then clear the created diagnostic codes.System Response:The start solenoid will not energize.Test Step 1. CHECK THE SOLENOID.
Turn the disconnect switch and the key start switch to the ON position. Do not start the engine. Ensure that the diagnostic code for the solenoid is active.
Disconnect the machine harness from the solenoid.
At the machine harness connector for the solenoid that is being tested, install a jumper wire. Install the jumper wire from contact 1 (306-GN(Green)) to contact 2 (E790-PK(Pink)).
Observe the status of the diagnostic code. The diagnostic code is active or the diagnostic code is NOT active. Expected Result:The status of the diagnostic code is active and the status of the diagnostic code is NOT active as the jumper is installed and then removed.Results:
YES - The circuit is correct.Repair: The solenoid has failed. Repeat the test step "CHECK THE SOLENOID" in order to verify that the solenoid has failed. Replace the solenoid.STOP
NO - The diagnostic code remains active. Proceed to test step 2.Test Step 2. CHECK THE SOLENOID CIRCUIT FOR AN OPEN.
The jumper that is between the signal wire and the return wire remains installed.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connector J2 from the ECM.
At the J2 machine harness connector for the ECM, measure the resistance from contact J1-8 for the solenoid to frame ground. Expected Result:There should be continuity (less than 5.0 ohms resistance).Results:
YES - The machine harness is correct. Proceed to test step 3.
NO - There is an open circuit in the machine harness.Repair: The open circuit is in the signal wire (306-GN(Green)) or in ground wire (E790-PK(Pink)) of the machine harness. Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS.
The contacts of the harness connectors should be cleaned and inspected.
Reconnect all of the harness connectors.
Turn the disconnect switch and the key start switch to the ON position.
Clear all of the inactive diagnostic codes.
Operate the machine.
Stop the machine and place the parking brake switch in the ON position.
Observe the status of the diagnostic code. The diagnostic code is active or the diagnostic code is NOT active. Expected Result:The diagnostic code is NO longer active.Results:
YES - The diagnostic code is NO longer active. The diagnostic code does not exist at this time. The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.STOP
NO - The diagnostic code has not been corrected. It is unlikely that the ECM has failed.Repair: Exit this procedure and perform this diagnostic code again.