FAN AS-CONDENSER 3508687 - Caterpillar

Transmission ECM
Table 1
Machine ECM (MID 27)
DTC Code Description System Response
702-03 Transmission Gear Lever Selector Sensor (Switch): Voltage Above Normal
702-04 Transmission Gear Lever Selector Sensor (Switch): Voltage Below Normal
1834-03 Ignition Key Switch: Voltage Above Normal Prior to beginning this procedure, inspect the harness connectors that are involved in this circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure, and in good condition. Check the wiring for pinch points or abrasions. Look for and repair areas that indicate wires are exposed. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing a troubleshooting procedure.Possible Causes for an FMI 03 are:
The ground wire is open.
A signal is permanently open.
The switch has failed.
The ECM has failed. A failure of the Transmission ECM is unlikely.Possible Causes for an FMI 04 are:
A short to ground.
The switch has failed.
The ECM has failed. A failure of the Transmission ECM is unlikely.The Transmission Downshift Switch is part of the Transmission Shift Assembly. The Transmission Downshift Switch is connected to two inputs of the ECM. One contact is open and the other contact is grounded during proper operation. Refer to Table 2.
Table 2
Status of the Downshift Switch
Switch Position G762-BR(Brown) Circuit
J1-43
N/O G761-YL(Yellow) Circuit
J1-42
N/C
Depressed Closed Open
Released Open Closed The Transmission Upshift Switch is part of the Transmission Shift Assembly. The Transmission Upshift Switch is connected to two inputs of the ECM. One contact is open and the other contact is grounded during proper operation. Refer to Table 3.
Table 3
Status for the Transmission Direction Switch 2
Switch Position J2-41 J2-40 J2-43 J2-42
Forward Closed Open Closed Open
Neutral Closed Open Open Closed
Reverse Open Closed Open Closed
Table 4
Troubleshooting Test Steps Values Results
1. Identify Active FMI Code Associated With Sensor Circuit
Code present. FMI 03 diagnostic code, proceed to Test Step 2.
FMI 04 diagnostic code, proceed to Test Step 7.
Begin Process For FMI 3 Troubleshooting HERE
2. Check the Harness For an Open
A. Turn key start switch and disconnect switch OFF.
B. Disconnect the switch from the machine harness.
C. Disconnect the J1 and J2 machine harness connector.
D. At the machine harness connector for the switch, place a jumper wire between the signal contact and frame ground.
E. At the machine harness connect for the ECM, measure the