Air Injection System
Secondary Air Injection (AIR) system Vehicles 08.95 -->Function
^ The AIR system injects air behind the exhaust valve for approx. 30 seconds (depending upon Engine coolant Temperature, load, RPM and air flow rate) during cold start (+5° C to +40° C engine coolant temperature). This injection produces an Oxygen rich exhaust gas, causes after burning and reduces the heat-up phase of the three-way catalytic converter.
^ Activation is initiated by the Motronic Engine Control Module (J220) via the AIR system pump relay (J299) to the AIR solenoid valve and Pneumatic-valve.
^ In addition to the cold start warm up phase of the engine, the AIR system is switched on during idling and checked via On Board Diagnostic (up to a maximum of 80° C Engine Coolant Temperature).
^ If the readiness code is being created; the Engine Coolant Temperature can also be above 80° C.
Creating the readiness code:
-> Repair group 01 in the Repair Manual, Readiness code, creating.
Secondary Air Injection (AIR) system components, removing and installing
Pneumatic-valve, checking
Special tools, testers and auxiliary items
^ Hand vacuum pump US 8026
Test sequence
- Pull vacuum hose -1- off Secondary Air Injection (AIR) solenoid valve -2-
- Connect hand vacuum pump US 8026 to vacuum hose -1-
- Disconnect pressure line from Pneumatic-valve
Note
Do not use compressed air for the following check.
- Connect auxiliary hose to Pneumatic-valve and blow into it
^ Pneumatic-valve must be closed
- Operate hand vacuum pump
^ Valve must open
^ Valve should operate smoothly (without sticking)
- Replace valve if necessary
Secondary Air Injection (AIR) system injection pump motor, checking
Special tools
^ VAG 1598/18 Test Box
^ VW 1594 connector test kit
^ VAG 1527B Voltage Tester
Checking requirement
^ Fuse -3- for AIR pump relay -4- OK
Checking sequence
- Switch OFF ignition
- Connect test box VAG 1598/18 to ECM wiring harness
- Disconnect pressure line from Pneumatic-valve
- Switch ON ignition
- Bridge Test Box sockets 01 + 06 using jumper wires from VW 1594 connector test kit
- Bridge test box socket 49 to Ground using jumper wires from VW 1594 connector test kit
^ AIR pump motor must run and air must exit the pressure line If the motor runs, but no air exits the hose
- Check pressure line, if necessary replace AIR pump motor If the AIR pump motor does not run
- Disconnect AIR pump motor
- Connect VAG 1527B Voltage tester to disconnected connector using jumper wires from VW 1594 connector test kit
^ Tester must light-up
If tester lights up (voltage supply OK)
- Replace AIR pump motor
If tester does NOT light up
- Check wiring between Test Box socket 49 and AIR pump relay using wiring diagram
- Check activation of relay and wiring to AIR pump motor using wiring diagram
- Reconnect 2-pin connector
- Interrogate and erase DTC memory
-> Repair group 01, On Board Diagnostic, Interrogating DTC memory
Secondary Air Injection (AIR) system solenoid valve
Special tools, testers and auxiliary items
^ VW 1594 connector test kit kit
^ VAG 1527B Voltage tester
^ US 8026 Hand vacuum pump
Checking requirement
^ Vacuum hoses OK
Checking sequence
- Disconnect vacuum hose to AIR solenoid valve at line to brake servo item 2
- Connect hand vacuum pump US 8026 to vacuum hose
- Disconnect Pneumatic valve vacuum hose at valve item 1
- Switch OFF ignition
- Connect test box VAG 1598/18 to ECM wiring harness
- Switch ON ignition
- Bridge test box sockets 01 + 06 using jumper wires from VW 1594 connector test kit
- Operate hand vacuum pump
^ Vacuum must build-up (valve closed)
If vacuum does not build-up
- Replace AIR solenoid valve -2-
If vacuum builds-up
- Connect test box socket 50 to Ground using jumper wires from VW 1594 connector test kit
^ Valve must open
- Operate hand vacuum pump
^ Vacuum must not build-up (valve open)
If vacuum builds-up
- Disconnect 2 pin harness connector from AIR solenoid valve
- Connect VAG 1527B Voltage tester to harness connector using jumper wires from VW 1594 connector test kit
^ Tester must light up
If tester lights up (voltage supply OK)
- Replace AIR solenoid valve
If tester does not light up
- Check wiring between Test Box socket 50 and terminal 2 of 2 pin harness connector for open circuit using wiring diagram
^ Resistance: 1.5 Ohms maximum
- Check wiring between central electric and AIR solenoid valve connector (terminal 1) using wiring diagram
- Connect 2 pin harness connector
- Interrogate and erase DTC memory,
-> Repair group 01; On Board Diagnostic; interrogating DTC memory