Secondary Air Injection System - Signal Implausible

P0410
Secondary Air Injection System - Signal Implausible (Cylinders 1 - 3)

P1411
Secondary Air Injection System - Signal Implausible (Cylinders 4 - 6)

Function
To improve emissions and to heat the three-way catalytic converter (TWC) faster, the secondary air injection pump is activated after the engine is started when cold, thus blowing secondary air behind the exhaust valves. If the engine temperature at start-up is less than -10 °C, the secondary air injection pump is disabled until the engine temperature has reached more than 44 °C. If the engine is started in a temperature range between -10 °C and 60 °C, the secondary air injection system is activated for a time depending on the start-up temperature. The secondary air injection system is deactivated under the following conditions:
Engine load > 4.5 ms
Air mass > 300 kg/h
Engine speed > 3800 rpm

A distinction is made between active and passive diagnosis. With passive diagnosis, testing is performed during the actual secondary air injection function. The sensor voltages ahead of the catalytic converter are evaluated. If passive diagnosis is interrupted, active diagnosis takes place with the engine idling. The secondary air injection pump is switched on for this purpose. The deviation of the oxygen sensors due to the excess oxygen is evaluated.

Diagnosis conditions







Passive diagnosis of the secondary air injection system is carried out under the following conditions:
- Diagnosis has not yet taken place during this cycle.
- The secondary air injection pump is switched on.
- The time after engine start-up is between 50 and 179 seconds.
- The engine speed lies between 680 and 2800 rpm.
- Engine load is between 0.7 ms and 3.0 ms.
- Air mass < 100 kg/h.
- Engine temperature > 30 °C.
- Vehicle must not be at an altitude of over 2448 m above sea level.
- No fault in the injection output stages.
- No fault in the voltage supply.
- No fault in fuel tank ventilation.
- No misfires harmful to TWC.
- No fault in the mass air flow (MAF) sensor.
- No fault in load sensing.
- Oxygen sensors 1 and 2 ahead of TWC are ready for operation.

Active diagnosis of the secondary air injection system is carried out under the following conditions:
- As yet no diagnosis with result.
- Secondary air injection function already performed in this driving cycle.
- Engine temperature between 10 °C and 95 °C.
- Intake air > -10 °C.
- Oxygen sensing system active.
- Idle speed.
- Stationary vehicle.
- No output stage faults in EVAP canister purge valve, secondary air injection pump or secondary air valve.
- No fault in fuel tank ventilation system, mass air flow sensor, voltage supply, throttle position sensor, oxygen sensor aging, engine temperature sensor and intake air temperature sensor.
- No misfires harmful to TWC.


Wiring Diagram







A - Relay of secondary air injection pump


System Overview







1 - Secondary air injection pump
2 - Air change-aver valve
3 - Electric change-over valve
4 - Nan-return valve
5 - To the cylinder heads
6 - Vacuum reservoir
7 - To the intake air system


Diagnosis Procedure







1 In menu "Drive links", trigger secondary air injection (AIR) pump.
1. Connect and switch on Porsche System Tester 2.
2. Select DME.
3. Call up "Drive links" menu.
4. Select AIR pump.
5. Activate AIR pump (audible function).

2 Check triggering of AIR pump.
1. Check fuse (Maxi Fuse) of AIR pump (on relay carrier 2).
2. Remove relay of AIR pump (on relay carrier 2). Connect voltmeter to pin 3 and ground.
Display: battery voltage
Connect voltmeter to pin 2 (negative) and pin 7 (positive).
Start engine (the DME relay must pick up).
Display: battery voltage

If 0 V is indicated, check wire from pin 2 to DME control module, pin 37, for continuity. Push relay back on.

3. Remove connector of AIR pump.
Connect voltmeter to pin 1 (positive) and pin 2 (negative).
Trigger AIR pump with Porsche System Tester 2.
Display: battery voltage

3 Check electric change-over valve.
1. Remove two-pole connector of change-over valve.
2. Connect voltmeter to pin 1 (positive) and pin 2 (negative).
3. Trigger AIR pump with Porsche System Tester 2.
Display: battery voltage
4. Remove vacuum hose of change-over valve with the engine running. Check whether vacuum is present.

4 Check air change-over valve and air supply lines.
1. Run engine briefly to produce vacuum.
2. Trigger AIR pump with Porsche System Tester 2.
3. Remove vacuum hose of air changeover valve.

If vacuum is present at the air changeover valve, check air supply from the AIR pump to the change-over valve to the air supply line to the cylinder heads.

Check function of air changeover valve.