The idle speed with warm engine is below the permissible range limit. (P1999)

The idle speed with warm engine is below the permissible range limit. (P1999)


Possible cause:

- M16/6 (Throttle valve actuator)
- Inspect the intake system of the engine for leaks.
Affected functions:

- Engine output

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Test 1: Check component M16/6 (Throttle valve actuator).

Test 2: Check air filter and intake tract for blockage.

1. Check component M16/6 (Throttle valve actuator).

Test 1.1: Check component M16/6 (Throttle valve actuator) using actual value.

Test 1.2: Check component M16/6m1 (Actuator motor) by means of actuation.

Test 1.3: Check internal resistance of component M16/6m1 (Actuator motor).

Test 1.4: Check internal resistance of component M16/6 (Throttle valve actuator).

Test 1.5: Test voltage supply of the potentiometers of component M16/6 (Throttle valve actuator).

1.1. Check component M16/6 (Throttle valve actuator) using actual value.
Warning!Communication with ECU required.


1.2. Check component M16/6m1 (Actuator motor) by means of actuation.
Test prerequisite

- Operate engine at idling speed.
Note

- If the throttle valve angle is< 1,1°, unmetered air may be present.
Status of relevant actual value:
- Throttle valve angle:Warning! Communication with ECU required.
Move on to actuation with button F2

1.3. Check internal resistance of component M16/6m1 (Actuator motor).
Figure legend

- A -ConnectionTest cable 35-pin socket box
- 001 -Sockets of component N3/10 (ME-SFI [ME] control unit)
- 05 -35-pin socket box
- 050 -126-pin socket box
- 108 -Test cable 266 589 01 63 00
- N3/10 (ME-SFI [ME] control unit)
- II 1-63ConnectionTest cable
- III 64-126ConnectionTest cable
Warning!

- Connection A of test cable 108 may NOT be connected to connection B of the 126-pin socket box (050).
Continue to test with button F2







Test sequence

- Switch off ignition.
- Disconnect coupling M at component N3/10 (ME-SFI [ME] control unit).
- Measure resistance with multimeter between sockets (M.75) 75 and (M.74) 74 of the 126-pole socket box tester.
Specified value

- Resistor[1...10]ohms
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

- Lines between N3/10 (ME-SFI [ME] control unit) and M16/6m1 (Actuator motor)
- M16/6m1 (Actuator motor)
End of test

1.4. Check internal resistance of component M16/6 (Throttle valve actuator).
Figure legend

- A -ConnectionTest cable 35-pin socket box
- 001 -Sockets of component N3/10 (ME-SFI [ME] control unit)
- 05 -35-pin socket box
- 050 -126-pin socket box
- 108 -Test cable 266 589 01 63 00
- N3/10 (ME-SFI [ME] control unit)
- II 1-63ConnectionTest cable
- III 64-126ConnectionTest cable
Warning!

- Connection A of test cable 108 may NOT be connected to connection B of the 126-pin socket box (050).
Continue to test with button F2







Test prerequisites

- The throttle flap of component M16/6 (Throttle valve actuator) should operate freely and must not stick or rub.
- At least one of the relevant actual values is not okay.
Test sequence

- Switch off ignition.
- Remove component B2/5 (Hot film mass air flow sensor).
- Disconnect coupling M at component N3/10 (ME-SFI [ME] control unit).
M16/6r3 (Actual value potentiometer (sliding contact 1))

- Measure resistance with multimeter between sockets (M.88) 88 and (M.43) 43 of the 126-pole socket box tester.
- Slowly operate throttle flap by hand up to full load.
Specified values

- Throttle valve not actuated[ca. 1380]ohms
- Throttle valve fully actuated[ca. 480]ohms
M16/6r4 (Actual value potentiometer (sliding contact 2))

- Measure resistance with multimeter between sockets (M.64) 64 and (M.43) 43 of the 126-pole socket box tester.
- Slowly operate throttle flap by hand up to full load.
Specified values

- Throttle valve not actuated[ca. 650]ohms
- Throttle valve fully actuated[ca. 1490]ohms
Question

- Are the measurement values OK?


YES
The measurement values are OK.Further possible causes of fault

- Test voltage supply of the potentiometers of component M16/6 (Throttle valve actuator).


NO
The measurement values are not OK.Possible cause and remedy

- Lines to component M16/6 (Throttle valve actuator)
- M16/6 (Throttle valve actuator)
End of test

1.5. Test voltage supply of the potentiometers of component M16/6 (Throttle valve actuator).
Test prerequisite

- At least one of the relevant actual values is not okay.
- The power supply of component N3/10 (ME-SFI [ME] control unit) is OK.
Test sequence

- Switch off ignition.
- Connect socket box (126-pin) to component N3/10 (ME-SFI [ME] control unit).
- Measure direct voltage with multimeter between sockets (M.39) 39 and (M.43) 43 of the 35-pole socket box tester.
- Switch on ignition.
Specified value

- Voltage[4.75...5.25] V
Question

- Is the measurement value OK?


YES
The measurement value is OK.Possible cause and remedy

- Check lines from component M16/6 (Throttle valve actuator) to component N3/10 (ME-SFI [ME] control unit).
End of test

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

- N3/10 (ME-SFI [ME] control unit)
End of test

2. Check air filter and intake tract for blockage.
Possible cause of fault

- Intake system clogged
Possible remedy

- Check entire air intake system for unmetered air.
End of test