Air Injection Pump: Testing and Inspection
SECONDARY AIR INJECTION SYSTEM, CHECKINGFunction-Overview
Vehicles 06-96>
The Secondary Air Injection system injects air behind the exhaust valve for approx. 30 seconds depending upon Engine Coolant Temperature, load, RPM and air flow rate, during the cold start. (+5°C to +40°C Engine Coolant Temperature)
Secondary Air Injection operation:
- Produces an Oxygen rich exhaust
- Causes after-burning
- Reduces the duration of the three-way catalyst heat-up phase
Activation is initiated by the Motronic Engine Control Module J220 via the Secondary Air Injection system pump relay J299 to the solenoid valve and Pneumatic-valve.
In addition to the engine cold start warm up phase, the Secondary Air Injection system is checked via On Board Diagnostic (up to an 80°C Engine Coolant Temperature, maximum)
If the readiness code is being created:
Engine Coolant Temperature can also be above 80°C
Secondary Air Injection System Components, Removing And Installing
NOTE: Complete system is checked via On Board Diagnostic.
1 Pneumatic-valve
Checking
See Below.
2 to brake servo line connector
3 Vacuum hose
4 2-pin harness connector
5 Secondary Air Injection solenoid valve
Checking:
See Below.
6 Pressure hose
Ensure it is securely seated
7 Secondary Air Injection system pump motor bracket
See Below.
8 10 Nm (7 ft lb)
9 NC hose bracket
10 10 Nm (7 ft lb)
11 25 Nm (18 ft lb)
12 Secondary Air Injection pump motor
- Checking:
See Below.
13 Secondary Air Injection pump intake hose
14 to Air Cleaner
15 to exhaust manifold union
16 30 Nm (22 ft lb)
17 Connector tube
18 10 Nm (7 ft lb)
19 10 Nm (7 ft lb)
20 Pneumatic-valve connector housing
21 25 Nm (18 ft lb)
22 Gasket
- Replace
23 Union
Pneumatic-valve, Checking
Special Tools, Testers And Auxiliary Items
- US 8026 Hand Vacuum Pump
Test Sequence
- Disconnect vacuum hose from Secondary Air Injection solenoid valve
- Attach US 8026 hand vacuum pump to vacuum hose
- 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 and operate smoothly (without sticking).
- Replace valve if necessary.
Secondary Air Injection pump motor, checking
Special tools
- VAG 1598/18 Test Box
- VW 1594 connector test kit
- VAG 1527B Voltage Tester
Checking requirement
- Secondary Air Injection pump relay fuse OK
Checking sequence
- Switch OFF ignition
- Connect VAG 1598/18 Test Box 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 adaptor kit.
- Bridge Test Box socket 49 to Ground using jumper wires from VW 1594 adaptor kit.
- pump motor must run and air must exit the pressure line.
If pump runs, but no air exits hose:
- Check pressure line, if necessary replace pump motor
If pump mot0r does not run:
- Disconnect pump motor harness connector
- Connect VAG 1 527B LED tester to disconnected connector using jumper wires from VW 1594 adaptor kit.
- LED tester must light-up.
If tester lights up (voltage supply OK):
- Replace pump motor
If tester does NOT light up:
- Check wiring between Test Box socket 49 and pump relay using wiring diagram.
- Check activation of relay and wiring to pump motor using wiring diagram
- Reconnect 2-pin harness connector.
- Check DTC memory, then erase.
Secondary Air Injection solenoid valve, Checking
Special Tools, Testers And Auxiliary Items
- WV 1594 adaptor kit
- VAG 1527B LED Tester
- US 8026 Hand vacuum pump
CHecking Requirement
- Vacuum hoses OK.
- Disconnect vacuum hose to solenoid valve at line to brake servo.
See Location Chart.
- Connect hand vacuum pump to vacuum hose.
- Disconnect Pneumatic valve vacuum hose at valve.
- Switch OFF ignition.
- Connect VAG 1598/18 Test Box to ECM wiring harness.
- Switch ON ignition.
- Bridge Test Box sockets 01 + 06 using jumper wires from WV 1594 adaptor kit.
- Operate hand vacuum pump.
- vacuum must build up (valve closed).
If Vacuum Does Not Build-up:
- Replace solenoid valve -2-
If Vacuum Builds Up:
- Connect Test Box socket 50 to Ground using jumper wires from WV 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 solenoid valve.
- Connect VAG 1527B LED tester to harness connector using jumper wires from WV 1594 adaptor kit.
- LED tester must light up.
If Tester Lights Up (voltage Supply OK):
- Replace solenoid valve.
If Tester Does Not Light Up:
- Check wiring for open circuit between Test Box socket 50 and terminal 2 of 2 pin harness connector using wiring diagram.
Resistance: 1.5 Ohms maximum.
- Check wiring between central electric and solenoid valve harness connector (terminal 1) using wiring diagram.
- Connect 2-pin harness connector.
- Check DTC memory, then erase.