Secondary Air Injection Sensor 1 -G609-, CHECKING

WARNING: This page is about a different car, the 2010 Audi Q7, 2009 Audi Q7, 2008 Audi Q7, and 2007 Audi Q7. However, it is still accessible from the selected car via links, so may be relevant.

General Description

The secondary air injection system blows air into the exhaust on a cold-start of the engine for 45 - 100 s and serves to quickly heat the catalytic converter(s) for improved emissions. A pressure based secondary air diagnostic function is used. In this system, the signal from the Secondary Air Injection Sensor 1 -G609- is evaluated by the Engine Control Module -J623-.

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 Manual 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 .
For Hybrid vehicles refer to: HIGH VOLTAGE SYSTEM GENERAL WARNINGS .

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	IGNITION: OFF. DISCONNECT: Secondary Air Injection Sensor 1 -G609- harness connector. IGNITION: ON. CHECK: Secondary Air Injection Sensor 1 -G609- harness connector terminals 1 to 3 for voltage. SPECIFIED VALUE: About 5.0 V. IGNITION: OFF. -- Was Value obtained?	-- YES: GO TO: Step 4 -- NO: GO TO: Step 3
3	REMOVE: Engine Control Module - J623-. Refer to appropriate repair information. CHECK: Secondary Air Injection Sensor 1 -G609- harness connector terminal 1 to the Engine Control Module - J623- harness connector T94 / 19 for resistance. CHECK: Secondary Air Injection Sensor 1 -G609- harness connector terminal 3 to the Engine Control Module - J623- harness connector T94 / 53 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Were Values obtained?	-- YES: GO TO: Step 5 -- 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 5
4	REMOVE: Engine Control Module - J623-. Refer to appropriate repair information. CHECK: Secondary Air Injection Sensor 1 -G609- harness connector terminal 2 to the Engine Control Module - J623- harness connector T94 / 38 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Was Value obtained?	-- YES: REPLACE: Secondary Air Injection Sensor 1 -G609-. Refer to appropriate repair information. GO TO: Step 5 -- 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 5
5	Final Procedure Perform a road test to verify repair. -- Does the original DTC return?	-- YES: CHECK: Engine Control Module -J623- harness connector for any damaged, pushed-out pins. REPAIR: As necessary. If all electrical connections are OK: REPLACE: Engine Control Module -J623-. Refer to appropriate repair information. Clear the DTCs. 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.