Exhaust Pressure Sensor 1 - G450-, CHECKING

Function 

Exhaust Gas Temperature Sensors are positive temperature coefficient (PTC) sensors. They measure the temperature of the exhaust gas. The ECM uses the signals from Exhaust Gas Temperature Sensors to calculate the amount of contamination in the diesel particulate filter, also to protect the turbocharger from unacceptably high exhaust gas temperatures. The diesel particulate filter contamination status is calculated using these signals from the Exhaust Gas Temperature Sensors, together with the signals from; Exhaust Pressure Sensor 1 -G450-, Differential Pressure Sensor -G505-, Exhaust Pressure Sensor 2 -G451-, Mass Airflow Sensor -G70-, and Heated Oxygen Sensor -G39-. The signal also serves as component protection in order to protect the diesel particulate filter and turbocharger from excessively high exhaust gas temperatures.

Special tools and workshop equipment required 

• Multimeter
• Wiring Diagram
• Scan Tool

Test requirements 

• Fuses OK.
• Battery voltage OK.
• Switch OFF all electrical and electronic accessories.
• Vehicles with Auto. Transmission, ensure Selector Lever position is in "P.".
• Vehicles with Man. Transmission, ensure Shifter Lever position is in "N" with Parking Brake applied.
• Coolant Temperature: ≥ 80 °C.
• Observe all safety precautions: SAFETY PRECAUTIONS .
• View clean working conditions: CLEAN WORKING CONDITIONS .

Test Procedure 

Step	Procedure	Result / Action to Take
1	PERFORM: Preliminary Check to verify the customers complaint. Refer to PRELIMINARY CHECK . -- Was Complaint verified?	YES: GO TO Step 2. NO: GATHER more information from customer about the complaint.
2	DISCONNECT: Exhaust Pressure Sensor 1 -G450- harness connector. IGNITION: ON. CHECK: Exhaust Pressure Sensor 1 -G450- wiring connector terminals 1 to 2 for voltage. SPECIFIED VALUE: About 5.0 V. IGNITION: OFF. -- Was Value obtained?	YES: GO TO: Step 3. NO: GO TO: Step 4.
3	REMOVE: Engine Control Module - J623-. CHECK: Exhaust Pressure Sensor 1 -G450- harness connector terminal 3 to the Engine Control Module - J623- harness connector T94 / 11 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Was Value obtained?	YES: REPLACE: Exhaust Pressure Sensor 1 -G450-. GO TO: Step 5. NO: CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 5.
4	REMOVE: Engine Control Module - J623-. CHECK: Exhaust Pressure Sensor 1 -G450- harness connector terminal 1 to the Engine Control Module - J623- harness connector T94 / 14 for resistance. CHECK: Exhaust Pressure Sensor 1 -G450- harness connector terminal 2 to the Engine Control Module - J623- harness connector T94 / 79 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Were Values obtained?	YES: REPLACE: Engine Control Module -J623-. GO TO: Step 5. NO: CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 5.
5	Final Procedure  Perform a road test to verify repair. Do any DTC's return:	YES: Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY . Perform the diagnostic procedure for that DTC. NO: Repair is complete. Generate readiness code. Refer to READINESS CODE . Return vehicle to Customer.