P20C9

Malfunction of secondary air injection at left bank of cylinders (function chain) (P0410)

Test 1: Check component M33 (electric air pump). ( Valid for (USA) , EURO 3 )

Test 2: Check component Y32/1 (air pump switchover valve, left bank of cylinders). ( Valid for (USA) , EURO 3 )

1. Check component M33 (electric air pump). ( Valid for (USA) , EURO 3 )

Test 1.1: Check component M33 (electric air pump) by means of actuation.

Test 1.2: Check power supply of component M33 (electric air pump).

Test 1.3: Check component K40/7kN (Air pump relay).

1.1. Check component M33 (electric air pump) by means of actuation.
Test prerequisite

- Engine at idle
- Actuate component M33 (electric air pump).(Actuate with key F2.)


Component M4/3 (engine/AC electric suction fan) runs with an on/off ratio of 50 % during the actuations for safety reasons.

Warning!Communication with ECU required.


1.2. Check power supply of component M33 (electric air pump).
Test prerequisite

- Actuation is not OK.
Test sequence

- Switch off ignition.
- (M33) Measure direct voltage with multimeter between 2 and 1 (M33)
- Switch on ignition.
- Actuate with key F2.
Specified value

- Voltage[11.0...14.5] V







Warning!Communication with ECU required.


1.3. Check component K40/7kN (Air pump relay).
Test prerequisites

- Actuation of component M33 (electric air pump) is not OK.
Test sequence

- Switch off ignition.
- Connect socket box (35-pin) to component N3/10 (ME-SFI [ME] control unit).
- Connect socket box (126-pin) to component N3/10 (ME-SFI [ME] control unit).
- Measure direct current with multimeter between socket (5.5) 5 of the 35-pole socket box tester and socket (4.22) 107 of the 126-pole socket box tester.
- Switch on ignition.
Warning!Perform the measurement only for a short time so that component M33 (electric air pump) does not overheat.Specified value

- Amperage[0.1...0.3] A
- Component M33 (electric air pump) is switched on and is heard to run.
Question

- Is the measurement value OK?


YES
The measurement value is OK.Question

- Does component M33 (electric air pump) run during the current measurement?


YES
The test was okay.End of test

NO
Test actuation of component M33 (electric air pump).
Figure legend

- M33 (electric air pump)
Test sequence

- Switch off ignition.
- Detach socket at component M33 (electric air pump).
- (M33) Measure direct voltage with multimeter between 2 and 1 (M33)
- Switch on ignition.
- Insert bridge for actuating component K40/7kN (Air pump relay).:
- Bridge between socket (5.5) 5 of the 35-pole socket box tester and socket (4.22) 107 of the 126-pole socket box tester.
Specified value

- Voltage[11.0...14.5] V
Question

- Is the measurement value OK?













YES
The measurement value is OK.Further possible causes of fault

- M33 (electric air pump)
End of test

NO
The measurement value is not OK.Possible cause and remedy

- Voltage supply of component K40/7kN (Air pump relay)
- K40/7kN (Air pump relay)
- Lines to component M33 (electric air pump)
- M33 (electric air pump)
End of test

NO
The measurement value is not OK.Possible cause and remedy

- Lines to component K40/7kN (Air pump relay)
- K40/7kN (Air pump relay)
End of test

2. Check component Y32/1 (air pump switchover valve, left bank of cylinders). ( Valid for (USA) , EURO 3 )

Test 2.1: Actuate component Y32/1 (air pump switchover valve, left bank of cylinders).

Test 2.2: Test current consumption of component Y32/1 (air pump switchover valve, left bank of cylinders).

Test 2.3: Test 'Secondary air injection left bank of cylinders' shutoff valve.

2.1. Actuate component Y32/1 (air pump switchover valve, left bank of cylinders).
Test sequence

- Ignition ON
- Actuate component Y32/1 (air pump switchover valve, left bank of cylinders).(Actuate with key F2.)


Component M4/3 (engine/AC electric suction fan) runs with an on/off ratio of 50 % during the actuations for safety reasons.

Warning!Communication with ECU required.


2.2. Test current consumption of component Y32/1 (air pump switchover valve, left bank of cylinders).
Test sequence

- Switch off ignition.
- Connect socket box (126-pin) to component N3/10 (ME-SFI [ME] control unit).
- Connect socket box (35-pin) to component N3/10 (ME-SFI [ME] control unit).
- Measure direct current with multimeter between socket (5.5) 5 of the 35-pole socket box tester and socket (2.6) 15 of the 126-pole socket box tester.
- Switch on ignition.
Specified value

- Component Y32/1 (air pump switchover valve, left bank of cylinders) is heard to operate.
- Amperage[0.3...0.5] A
Question

- Is the measurement value OK?


YES
The measurement value is OK.End of test

NO
The measurement value is not OK.Possible cause and remedy

- Voltage supply of component Y32/1 (air pump switchover valve, left bank of cylinders)
- Lines to component Y32/1 (air pump switchover valve, left bank of cylinders)
- Y32/1 (air pump switchover valve, left bank of cylinders)
End of test

2.3. Test 'Secondary air injection left bank of cylinders' shutoff valve.
Figure legend

- 019Vacuum tester
- 126/1'Secondary air injection right bank of cylinders' shutoff valve
- 126/2'Secondary air injection left bank of cylinders' shutoff valve
The illustration shows the connection of the vacuum tester for example at component 126/1.Test prerequisites

- Actuation of component Y32/1 (air pump switchover valve, left bank of cylinders) was OK.
Test sequence

- Detach shaped hose at component 126/1.
- Connect vacuum tester to component 126/1.
- Use the vacuum tester to set a vacuum of 20 mbar.
Question

- Is the vacuum achieved?







YES
Figure legend

- 019Vacuum tester
- 126/1'Secondary air injection right bank of cylinders' shutoff valve
- 126/2'Secondary air injection left bank of cylinders' shutoff valve
The illustration shows the connection of the vacuum tester for example at component 126/1.Test sequence

- Connect vacuum tester to component 126/1.
- Run engine.
- Use the vacuum tester to set a vacuum of 20...25 mbar.
Specified value

- When vacuum is supplied to component 126/1, the shutoff valve opens, as a result of which a perceptible suction can be felt at the connection flange.(See arrow)
Question

- Was the test o.k.?







YES
The test was okay.End of test

NO
The test was not okay.Possible cause and remedy

- 'Secondary air injection left bank of cylinders' shutoff valve
End of test

NO
The test was not okay.Possible cause and remedy

- 'Secondary air injection left bank of cylinders' shutoff valve
End of test