Exhaust System: Testing and Inspection

Exhaust system, checking for proper seal
^ Start engine and let run at idle.
^ Seal tailpipes with cloths or plug for the duration of the leak test.
^ Check for leaks by listening at cylinder head exhaust manifold, exhaust manifold/front exhaust pipe etc.
^ Repair leaks.

Secondary air system
The Secondary Air Injection (AIR) system causes the catalytic converter to heat up more quickly, resulting in earlier operating readiness following cold start.

Principle
Due to over-enrichment of the mixture during the cold start phase, there is an increased amount of uncombusted carbon monoxide in the exhaust. Secondary Air Injection (AIR) improves secondary oxidation in the catalytic converter and therefore reduces emissions. The heat produced by secondary oxidation greatly reduces start-up time for the catalytic converter, therefore improving exhaust quality during the cold start phase significantly.

Function
- In the cold start phase, the ECM -4- activates the secondary air pump -2- via the relay for secondary air injection -3-. Air reaches the combination valves for Secondary Air Injection (AIR) -5- and -9
- The Secondary Air Injection (AIR) valve -6- is activated in parallel, which allows the vacuum to reach the combination valves for Secondary Air Injection (AIR) -5- and -9-. The appropriate combination valve for Secondary Air Injection (AIR) thereby opens the path for secondary air to the exhaust channels of the cylinder head.





1. From air filter housing
2. Secondary Air Injection (AIR) Pump Motor -V1 01 -
^ Component location, Refer to Fig 2
^ Removing and installing, Refer to Air Injection
3. Secondary Air Injection (AIR) Pump Relay -J299
^ Component location, Refer to Fig 3
4. Motronic Engine Control Module (ECM) -J220
5. Combination valve for secondary air injection (right)
^ Component location, Refer to Fig 3
^ Checking, Refer to Air Injection, Testing and Inspection
^ Removing and installing, Refer to Air Injection, Service and Repair
6. Secondary Air Injection (AIR) Solenoid Valve -N1 12
7. Check-valve
^ Installed position (light/dark side): Arrow points in direction of flow, as shown in figure.
8. To Intake manifold
9. Combination valve for secondary air injection (left)
^ Component location, Refer to Fig 3
^ Checking, Refer to Air Injection, Testing and Inspection
^ Removing and installing, Refer to Air Injection, Service and Repair
10. Vacuum reservoir
^ Installation location: Under wheel housing liner in front left wheel housing





Fig. 1 Component location Secondary Air Injection (AIR) Solenoid Valve -N112
^ Bolted to holding plate for solenoid valves at rear of engine (arrow).





Fig. 2 Secondary Air Injection (AIR) Pump Motor -V101
^ At front right in engine compartment below air filter housing
1. Secondary Air Injection (AIR) Pump Motor -V101
2. Electrical harness connector for Secondary Air Injection (AIR) Pump Motor -V101 -





Fig. 3 Secondary Air Injection (AIR) Pump Relay -J299-
In E-box, plenum chamber
3 Secondary Air Injection (AIR) Pump Relay -J299
B - Fuse for secondary air pump -S130





Fig. 4 Combination valve for secondary air injection (AIR)
^ At rear of cylinder heads

Note: Right valve is shown in illustration.