C3.4B Engines Caterpillar

Sensor Signal (Analog, Passive) - Test

Usage:

CCS7 4B2

This procedure covers the following codes:

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Table 1
Diagnostic Trouble Codes for the Engine Temperature Sensors
J1939 Code	Description	Notes
105-3	Engine Intake Manifold #1 Temperature : Voltage Above Normal	The Electronic Control Module (ECM) detects the following conditions: The signal voltage for the intake manifold temperature sensor is greater than 4.94 VDC for at least 0.5 seconds. The battery voltage is at least 10 VDC. The warning lamp will flash. The engine will be derated.
105-4	Engine Intake Manifold #1 Temperature : Voltage Below Normal	The ECM detects the following conditions: The signal voltage for the intake manifold temperature sensor is less than 0.2 VDC for at least 0.5 seconds. The battery voltage is at least 10 VDC. The warning lamp will flash. The engine will be derated.
110-3	Engine Coolant Temperature : Voltage Above Normal	The ECM detects that the signal voltage for the coolant temperature sensor is greater than 4.93 VDC for at least 0.5 seconds. The ECM will use the default value for the coolant temperature while this diagnostic code is active. The default value is −10° C (14° F) at engine start, gradually increasing to 90° C (194° F) as the engine is running. The warning lamp will flash. The engine will be derated.
110-4	Engine Coolant Temperature : Voltage Below Normal	The ECM detects that the signal voltage for the coolant temperature sensor is less than 0.2 VDC for at least 0.5 seconds. The ECM will use the default value for the coolant temperature while this diagnostic code is active. The default value is −10° C (14° F) at engine start, gradually increasing to 90° C (194° F) as the engine is running. The warning lamp will flash. The engine will be derated.
172-3	Engine Air Inlet Temperature : Voltage Above Normal	The ECM detects that the signal voltage for the air inlet temperature sensor is greater than 4.93 VDC for at least 0.5 seconds. While this code is active, the ECM will gradually increase or decrease the air inlet temperature from the last valid reading until the default value is reached. The default value is 30° C (86° F). The warning lamp will come on.
172-4	Engine Air Inlet Temperature : Voltage Below Normal	The ECM detects that the signal voltage for the air inlet temperature sensor is less than 0.2 VDC for at least 0.5 seconds. While this code is active, the ECM will gradually increase or decrease the air inlet temperature from the last valid reading until the default value is reached. The default value is 30° C (86° F). The warning lamp will come on.
173-3	Engine Exhaust Gas Temperature : Voltage Above Normal	The ECM detects the following conditions: The signal from the exhaust gas temperature sensor is greater than 3.6 VDC for at least 1 second. The battery voltage is at least 10 VDC. While this code is active, the ECM will use the default value for the exhaust gas temperature. The default value is 350° C (662° F). The warning lamp will come on. The engine will be derated.
173-4	Engine Exhaust Gas Temperature : Voltage Below Normal	The ECM detects that the signal from the exhaust gas temperature sensor is less than 0.46 VDC for at least 1 second. While this code is active, the ECM will use the default value for the exhaust gas temperature. The default value is 350° C (662° F). The warning lamp will come on. The engine will be derated.
174-3	Engine Fuel Temperature 1 : Voltage Above Normal	The ECM detects that the signal voltage for the fuel temperature sensor is greater than 4.93 VDC for at least 0.5 seconds. The ECM will use a default value for the fuel temperature while this code is active. The default value will be based on the coolant temperature. If the coolant temperature sensor has an active fault, the default value for the fuel temperature is 40° C (104° F). The warning lamp will come on.
174-4	Engine Fuel Temperature 1 : Voltage Below Normal	The ECM detects that the signal voltage for the fuel temperature sensor is less than 0.2 VDC for at least 0.5 seconds. The ECM will use a default value for the fuel temperature while this code is active. The default value will be based on the coolant temperature. If the coolant temperature sensor has an active fault, the default value for the fuel temperature is 40° C (104° F). The warning lamp will come on.
4360-3	Aftertreatment #1 SCR Catalyst Intake Gas Temperature : Voltage Above Normal	The ECM detects that the signal voltage for the Selective Catalytic Reduction (SCR) inlet temperature sensor is greater than 3.6 VDC for at least 1 second. The ECM will use the default value for the SCR inlet temperature while this code is active. The default temperature is 0.06° C (32.1° F). The warning lamp will come on.
4360-4	Aftertreatment #1 SCR Catalyst Intake Gas Temperature : Voltage Below Normal	The ECM detects that the signal voltage for the SCR inlet temperature sensor is less than 0.46 VDC for at least 1 second. The ECM will use the default value for the SCR inlet temperature while this code is active. The default temperature is 0.06° C (32.1° F). The warning lamp will come on.
4363-3	Aftertreatment #1 SCR Catalyst Outlet Gas Temperature : Voltage Above Normal	The ECM detects that the signal voltage for the Selective Catalytic Reduction (SCR) outlet temperature sensor is greater than 3.3 VDC for at least 1 second. The ECM will use the default value for the SCR outlet temperature while this code is active. The default temperature is 41° C (106° F). The warning lamp will come on.
4363-4	Aftertreatment #1 SCR Catalyst Outlet Gas Temperature : Voltage Below Normal	The ECM detects that the signal voltage for the SCR outlet temperature sensor is less than 0.2 VDC for at least 1 second. The ECM will use the default value for the SCR outlet temperature while this code is active. The default temperature is 41° C (106° F). The warning lamp will come on.
4765-3	Aftertreatment #1 Diesel Oxidation Catalyst Intake Gas Temperature : Voltage Above Normal	The ECM detects that the signal voltage for the Diesel Oxidation Catalyst (DOC) inlet temperature sensor is greater than 3.6 VDC for at least 1 second. The ECM will use the default value for the DOC inlet temperature sensor while this code is active. The default value is 80° C (176° F). The warning lamp will come on.
4765-4	Aftertreatment #1 Diesel Oxidation Catalyst Intake Gas Temperature : Voltage Below Normal	The ECM detects that the signal voltage for the DOC inlet temperature sensor is less than 0.46 VDC for at least 1 second. The ECM will use the default value for the DOC inlet temperature sensor while this code is active. The default value is 80° C (176° F). The warning lamp will come on.

This procedure covers open circuit diagnostic codes and short circuit diagnostic codes that are associated with the following sensors:

Intake manifold temperature sensor
Coolant temperature sensor
Exhaust gas temperature sensor
Fuel temperature sensor
Air inlet temperature sensor
DOC inlet temperature sensor
SCR inlet temperature sensor
SCR outlet temperature sensor

The following background information is related to this procedure:

The troubleshooting procedures for the diagnostic codes of each temperature sensor are identical. The temperature sensors have two terminals. The signal voltage from each sensor is supplied to the appropriate terminal in the P2/J2 connector or the P1/J1 connector.

Pull-up Voltage

The ECM continuously outputs a pull-up voltage on the circuit for the sensor signal wire. This pull-up voltage is required for correct sensor operation and diagnostics.

When the sensor is disconnected, this pull-up voltage can be measured at the harness connector for the sensor.

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Illustration 1	g03732617
Schematic diagram for the engine temperature sensors Not all connectors are shown. Refer to the Electrical Schematic for the application.

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Illustration 2	g03732635
Typical view of the pin locations for the temperature sensors on the 62-pin engine interface connector (13) Coolant temperature sensor ground (14) Coolant temperature sensor signal (15) Fuel temperature sensor ground (16) Fuel temperature sensor signal (19) Intake manifold temperature sensor ground (20) Intake manifold temperature sensor signal (25) Exhaust gas temperature sensor signal (26) Exhaust gas temperature sensor ground

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Illustration 3	g03732637
Typical view of the P2 pin locations for the temperature sensors (23) Engine fuel temperature sensor ground (25) Intake manifold temperature sensor ground (27) Exhaust gas temperature sensor ground (38) Engine fuel temperature sensor signal (43) Exhaust gas temperature sensor signal (55) Intake manifold temperature sensor signal (57) Coolant temperature sensor signal (58) Intake manifold temperature sensor ground

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Illustration 4	g03732649
Typical view of the P1 pin locations for the temperature sensors (19) Air inlet temperature sensor signal (20) Air inlet temperature sensor ground (56) DOC inlet temperature sensor signal (65) DOC inlet temperature sensor ground (79) SCR outlet temperature sensor ground (80) SCR outlet temperature sensor signal (81) SCR inlet temperature sensor ground (82) SCR inlet temperature sensor signal

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Table 2
Troubleshooting Test Steps	Values	Results
1. Check for Diagnostic Trouble Codes A. Connect to the electronic service tool. B. Turn the keyswitch to the ON position. C. Access the "Active Diagnostic Code" screen on the electronic service tool. Wait at least 30 seconds in order for the diagnostic codes to become active. D. Check if any of the diagnostic codes listed in Table 1 are active or recently logged.	Codes	Result: A -3 diagnostic code is active. Proceed to Test Step 2. Result: A -4 diagnostic code is active. Proceed to Test Step 3. Result: If a diagnostic code is logged but not currently active, the fault may be intermittent. Refer to Troubleshooting, "Electrical Connectors - Inspect" in order to identify intermittent faults.
2. Create a Short at the Sensor Connector A. Turn the keyswitch to the OFF position. B. Disconnect the suspect sensor. C. Install the jumper wire between terminal 1 (sensor signal) and terminal 2 (sensor return) at the sensor connector. D. Turn the keyswitch to the ON position. E. Monitor the diagnostic codes on the electronic service tool. Check for an active -4 diagnostic code for the suspect sensor. Wait at least 30 seconds in order for the diagnostic codes to become active. F. Turn the keyswitch to the OFF position.	Short Circuit Recognized	Result: The -3 diagnostic code remains active for the suspect sensor. The fault is in the wiring for the suspect sensor. Repair: Check all wiring between the suspect sensor and the ECM. Refer to the appropriate Electrical Schematic. Replace the faulty wiring. Verify that the problem is resolved. Result: A -4 diagnostic code became active after creating the short at the sensor connector. Repair: The wiring is OK. Replace the suspect sensor. Verify that the problem is resolved.
3. Create an Open Circuit at the Suspect Sensor Connector A. Turn the keyswitch to the OFF position. B. Disconnect the sensor connector of the suspect sensor with the active -4 diagnostic code. C. Turn the keyswitch to the ON position. D. Monitor the diagnostic codes on the electronic service tool. Check for an active -3 diagnostic code for the suspect sensor. Wait at least 30 seconds in order for the diagnostic codes to become active. E. Turn the keyswitch to the OFF position.	Open Circuit Recognized	Result: The -4 diagnostic code remains active for the suspect sensor. The fault is in the wiring for the suspect sensor. Repair: Check all wiring between the suspect sensor and the ECM. Refer to the appropriate Electrical Schematic. Replace the faulty wiring. Verify that the problem is resolved. Result: A -3 diagnostic code became active after disconnecting the sensor. Repair: The wiring is OK. Replace the sensor. Verify that the problem is resolved.
If the procedure did not correct the fault, contact the Dealer Solution Network (DSN).