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Home >> Mercedes Benz >> 2002 >> S 600 (220.178) V12-5.8L (137.970) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P20D4

P20D4


The load limit is active.

Test 1: Check self-adaptation of mixture formation.

Test 2: Check component B2/5 (Hot film mass air flow sensor).

Test 3: Check component B2/5b1 (Intake air temperature sensor).

Test 4: Check component M16/6 (Throttle valve actuator).

1. Check self-adaptation of mixture formation.
Warning!Communication with ECU required.


2. Check component B2/5 (Hot film mass air flow sensor).

Test 2.1: Check component B2/5 (Hot film mass air flow sensor) using actual value.

Test 2.2: Test signal voltage of component B2/5 (Hot film mass air flow sensor) by means of actual value.

Test 2.3: Check power supply of component B2/5 (Hot film mass air flow sensor).

2.1. Check component B2/5 (Hot film mass air flow sensor) using actual value.
Test prerequisite

- AC off
- Temperature of coolant>70° C
- Engine at idle
Status of the relevant actual values:
- Air conditioning:Warning!
- Temperature of coolant:Warning! Communication with ECU required.
- Air mass:Warning! Communication with ECU required.
Specified values

- Air mass: [24.0...32.0] kg/h(If engine speed rises, the air mass increases.)
Question

- Are the actual values o.k.?


YES
The actual values are okay.Possible cause and remedy

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

NO
The actual values are not okay.Possible cause and remedy

- Check power supply of component B2/5 (Hot film mass air flow sensor).
- Check lines from component N3/10 (ME-SFI [ME] control unit) to component B2/5 (Hot film mass air flow sensor).
- Unmetered air
- B2/5 (Hot film mass air flow sensor)


2.2. Test signal voltage of component B2/5 (Hot film mass air flow sensor) by means of actual value.
Test prerequisite

- Battery voltage is OK.
- Voltage supply of component B2/5 (Hot film mass air flow sensor): [11...14,5] V
- Engine OFF
- Ignition ON
Status of relevant actual value:
- HFM-SFI voltage:Warning! Communication with ECU required.
Specified value:

- Voltage [0,980...1,020] V
Question

- Are the measurement values OK?


YES
The actual values are okay.Possible cause and remedy

- Check assignment of component B2/5 (Hot film mass air flow sensor) to engine model designation.
End of test

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

- Check power supply of component B2/5 (Hot film mass air flow sensor).
- Check lines from component N3/10 (ME-SFI [ME] control unit) to component B2/5 (Hot film mass air flow sensor).
- B2/5 (Hot film mass air flow sensor)


2.3. Check power supply of component B2/5 (Hot film mass air flow sensor).
Test prerequisite

- The actual value is not o.k.
Test sequence

- Switch off ignition.
- Detach coupling at component B2/5 (Hot film mass air flow sensor).
- Measure direct voltage with multimeter between sockets (B2/5) 3 and (B2/5) 2
- Switch on ignition.
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

- Unmetered air
- Signal wire
- B2/5 (Hot film mass air flow sensor)
End of test

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

- Cable for voltage supply
End of test

3. Check component B2/5b1 (Intake air temperature sensor).

Test 3.1: Check component B2/5b1 (Intake air temperature sensor) using actual value.

Test 3.2: Check plausibility of actual value B2/5b1 (Intake air temperature sensor) in control module ME-SFI 2.7.

Test 3.3: Check internal resistance of component B2/5b1 (Intake air temperature sensor).

3.1. Check component B2/5b1 (Intake air temperature sensor) using actual value.
Test sequence

- Switch on ignition.
Status of relevant actual value:
- Temperature of intake air:Warning! Communication with ECU required.
Specified value

- Current temperature in area surrounding component B2/5b1 (Intake air temperature sensor)
Question

- Is the actual value o.k.?


YES
The actual value is okay.End of test

NO
The actual value is not o.k.Possible cause and remedy

- Check plausibility of actual value B2/5b1 (Intake air temperature sensor) in control module N3/10 (ME-SFI [ME] control unit).
- Check internal resistance of component B2/5b1 (Intake air temperature sensor).


3.2. Check plausibility of actual value B2/5b1 (Intake air temperature sensor) in control module ME-SFI 2.7.
Test prerequisite

- The actual value is not o.k.
Test sequence

- Detach socket at component B2/5 (Hot film mass air flow sensor).
- Switch on ignition.
Status of relevant actual value:
- Temperature of intake air:Warning! Communication with ECU required.
Specified value

- If the connection is unplugged at component B2/5b1 (Intake air temperature sensor), the value is approx. [ -40° C ].
- Bridge pin 1 in pin 3 at the unplugged connection of component B2/5b1 (Intake air temperature sensor).The value is approx. [ 150° C ].
Question

- Is the actual value o.k.?







YES
The actual value is okay.Further possible causes of fault

- Check internal resistance of component B2/5b1 (Intake air temperature sensor).


NO
The actual value is not o.k.Possible cause and remedy

- Signal wire
End of test

3.3. Check internal resistance of component B2/5b1 (Intake air temperature sensor).
Test sequence

- Switch off ignition.
- Detach coupling at component B2/5 (Hot film mass air flow sensor).
- Measure resistance with multimeter between pins (B2/5) 1 and (B2/5) 3
Specified value

- Resistor(10° C): [3420...3780]ohms
- Resistor(20° C): [2299...2541]ohms
- Resistor(30° C): [1577...1743]ohms
- Resistor(40° C): [1122...1229]ohms
- Resistor(50° C): [808...893]ohms
- Resistor(60° C): [570...630]ohms
Question

- Are the measurement values OK?







YES
The measurement values are OK.End of test

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

- B2/5b1 (Intake air temperature sensor)
End of test

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

Test 4.1: Check component M16/6 (Throttle valve actuator) using actual value.

Test 4.2: Actuate component M16/6m1 (Actuator motor).

Test 4.3: Check internal resistance of component M16/6m1 (Actuator motor).

Test 4.4: Test series resistance of actual value potentiometers of component M16/6m1 (Actuator motor).

Test 4.5: Test voltage supply of the potentiometers of component M16/6 (Throttle valve actuator).

4.1. Check component M16/6 (Throttle valve actuator) using actual value.
Test prerequisite

- The engine is running.
Status of the relevant actual values:
- M16/6 (Throttle valve actuator) Signal 1:Warning! Communication with ECU required.
- M16/6 (Throttle valve actuator) Signal 2:Warning! Communication with ECU required.
Specified values

- M16/6 (Throttle valve actuator)Signal 1(Idle speed): [0.30...0.90] V
- M16/6 (Throttle valve actuator)Signal 2(Idle speed): [4.00...4.60] V
- M16/6 (Throttle valve actuator)Signal 1(Full load):[4.00...4.60] V
- M16/6 (Throttle valve actuator)Signal 2(Full load):[0.30...0.90] V
Question

- Are the actual values o.k.?


YES
The actual values are okay.End of test

NO
At least one of the relevant actual values is not okay.Possible cause and remedy

- Test series resistance of actual value potentiometers of component M16/6m1 (Actuator motor).
- Check power supply of component M16/6 (Throttle valve actuator).


4.2. Actuate component M16/6m1 (Actuator motor).
Warning!Communication with ECU required.


4.3. Check internal resistance of component M16/6m1 (Actuator motor).
Test prerequisite

- The actual values are not okay.
Test sequence

- Switch off ignition.
- Disconnect coupling 1 at component N3/10 (ME-SFI [ME] control unit).
- (N3/10) 1.Measure resistance with multimeter between sockets 6 and 1.3 (N3/10)
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)


4.4. Test series resistance of actual value potentiometers of component M16/6m1 (Actuator motor).
Test prerequisites

- At least one of the relevant actual values is not okay.
Test sequence

- Switch off ignition.
- Disconnect coupling 2 at component N3/10 (ME-SFI [ME] control unit).
- (N3/10) 2.Measure resistance with multimeter between sockets 2 and 2.3 (N3/10)
Specified value

- Resistor[1800...2000]ohms
Question

- Is the measurement value OK?


YES
The measurement value is OK.Test prerequisites

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

- Switch off ignition.
- Remove component B2/5 (Hot film mass air flow sensor).
- Disconnect coupling 2 at component N3/10 (ME-SFI [ME] control unit).
M16/6r1 (Throttle valve actual value potentiometer)

- (N3/10) 2.Measure resistance with multimeter between sockets 9 and 2.3 (N3/10)
- Slowly operate throttle flap by hand up to full load.
Specified values

- Idle speed[ca. 650]ohms
- Full load[ca. 1490]ohms
M16/6r2 (Drive actual value potentiometer)

- (N3/10) 2.Measure resistance with multimeter between sockets 9 and 2.2 (N3/10)
- Slowly operate throttle flap by hand up to full load.
Specified values

- Idle speed[ca. 1380]ohms
- Full load[ca. 480]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)


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

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


4.5. 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.
- Detach coupling at component M16/6 (Throttle valve actuator).
- Measure direct voltage with multimeter between pins (M16/6) 2 and (M16/6) 3
- Switch on ignition.
Specified value

- Voltage[4.75...5.25] V
Question

- Is the measurement value OK?







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

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

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

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

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