Outside Air Temperature Sensor - G17-, Checking

General Description

The ambient or Outside Air Temperature Sensor -G17- is a negative temperature coefficient (NTC) sensor that informs the semiautomatic / automatic temperature control system of outside air temperature. An NTC sensor resistance decreases as the temperature increases, and the sensor resistance increases as the temperature decreases. The computer uses this input along with different in-car temperature sensors to control temperature and blower speed. When there is a problem with this sensor, performance will suffer and the A/C compressor clutch may not engage.

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 automatic transmission, ensure the selector lever position is in "P".
Vehicles with manual transmission, ensure the shifter lever position is in "N" with the parking brake applied.
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 Outside Air Temperature Sensor - G17-, CHECKING - 2 . -- NO: GATHER more information from customer about the complaint.
2	IGNITION: OFF. DISCONNECT: Outside Air Temperature Sensor -G17- harness connector. CHECK: Outside Air Temperature Sensor -G17- component connector terminals 1 to 2 for resistance. SPECIFIED VALUE: 1, 300 Ω (+/- 500 Ω @ approx. 20° C). -- Was Value obtained?	-- YES: GO TO: Step 3 Outside Air Temperature Sensor - G17-, CHECKING - 3 . -- NO: REPLACE: Outside Air Temperature Sensor -G17-. Refer to appropriate Service Information. GO TO: Step 4 Outside Air Temperature Sensor - G17-, CHECKING - 4 .
3	REMOVE: Vehicle Electrical System Control Module -J519-. Refer to appropriate Service Information. CHECK: Outside Air Temperature Sensor -G17- harness connector terminal 1 to the Vehicle Electrical System Control Module -J519- harness connector T46a / 19 for resistance. CHECK: Outside Air Temperature Sensor -G17- harness connector terminal 2 to the Vehicle Electrical System Control Module -J519- harness connector T46a / 27 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Were Values obtained?	-- YES: TIP: The Outside Air Temperature Sensor -G17- may fail under loaded operation; please swap a known good Outside Air Temperature Sensor -G17- prior to continuing to the next step. GO TO: Step 4 Outside Air Temperature Sensor - G17-, CHECKING - 4 . -- NO: PERFORM: Visual Inspection of wiring and component. 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 4 Outside Air Temperature Sensor - G17-, CHECKING - 4 .
4	Final Procedure Perform a road test to verify repair. -- Does the original DTC return?	-- YES: CHECK: Vehicle Electrical System Control Module -J519- harness connector for any damaged, pushed-out pins. REPAIR: As necessary. If all electrical connections are OK: REPLACE: Vehicle Electrical System Control Module -J519-. Refer to appropriate Service Information. Clear the DTC's. Refer to DIAGNOSTIC MODE 04 -- ERASE DTC MEMORY -->. Repair is complete. Generate Readiness Code. Refer to READINESS CODE . Return vehicle to Customer. -- NO: Perform the diagnostic procedure for any DTC's. If no DTC's return, the repair is complete. Return vehicle to customer.