GASKET-PLATE 7N7997 - Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with the passive sensors. Also, use this procedure if any one of the diagnostic codes is active or easily repeated.
Table 1
J1939 Code and Description Comments
105-3
Engine Intake Manifold #1 Temperature : Voltage Above Normal The Electronic Control Module (ECM) detects signal voltage that is not in the acceptable range.
The value of the parameter is set to a default value.
The code is logged.
105-4
Engine Intake Manifold #1 Temperature : Voltage Below Normal The ECM detects signal voltage that is not in the acceptable range.
The value of the parameter is set to a default value.
The code is logged.
110-3
Engine Coolant Temperature : Voltage Above Normal The ECM detects signal voltage that is not in the acceptable range.
The value of the parameter is set to a default value.
The code is logged.
Note: For a 110-3 code, start the engine and let the engine idle for 7 minutes. The engine must be running for at least 7 minutes in order for the diagnostic to run.
110-4
Engine Coolant Temperature : Voltage Below Normal The ECM detects signal voltage that is not in the acceptable range.
The value of the parameter is set to a default value.
The code is logged.
171-3
Ambient Air Temperature : Voltage Above Normal The ECM detects signal voltage that is not in the acceptable range.
The value of the parameter is set to a default value.
The code is logged.
171-4
Ambient Air Temperature : Voltage Below Normal The ECM detects signal voltage that is not in the acceptable range.
The value of the parameter is set to a default value.
The code is logged.
175-3
Engine Oil Temperature 1 : Voltage Above Normal The ECM detects signal voltage that is not in the acceptable range.
The value of the parameter is set to a default value.
The code is logged.
175-4
Engine Oil Temperature 1 : Voltage Below Normal The ECM detects signal voltage that is not in the acceptable range.
The value of the parameter is set to a default value.
The code is logged. The sensor signal for the passive sensor is routed from the ECM to terminal 1 of the sensor connector. The sensor return for the passive sensors is routed from the ECM to terminal 2 of the sensor connector.When the ECM detects voltage that is above a threshold on the signal wire, the ECM activates a high voltage -3 diagnostic code. When the ECM detects voltage that is below a threshold on the signal wire, the ECM activates a low voltage -4 diagnostic code.Note: There may be a delay of 30 seconds or more in order for Cat® Electronic Technician (ET) to display an active diagnostic code. When you check for a diagnostic code, be sure to wait at least 30 seconds.
Illustration 1 g06120726
For the complete circuit details, refer to the full schematic.
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Determine if a code is active or logged.
Codes
Result: A -3 code is active.
Proceed