The load limit is active. (P0221)

The load limit is active. (P0221)

Possible cause:

- B17/8 (Charge air temperature sensor)
- Charge pressure control
- M16/6 (Throttle valve actuator)
Affected functions:

- Engine output

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

Test 2: Preconditions for test B17/8 (Charge air temperature sensor)

Test 3: The load limit is active.

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

Test 1.1: Actuate component M16/6m1 (Actuator motor).

Test 1.2: Check component M16/6 (Throttle valve actuator) using actual value.

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

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

- Ignition ON
Status of the relevant actual values:
- Throttle valve stop learned:Warning!
- 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):[2.20...2.60] V
- M16/6 (Throttle valve actuator)Signal 2(Full load):[2.40...2.80] 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

- Check internal resistance of component M16/6m1 (Actuator motor).
- Check internal resistance of component M16/6 (Throttle valve actuator).
- Check power supply of component M16/6 (Throttle valve actuator).

1.3. 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 9 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)

1.4. Check internal resistance of component M16/6 (Throttle valve actuator).
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 air scoop at component M16/6 (Throttle valve actuator) (to do so, loosen charge air cooler).
- Disconnect coupling 2 at component N3/10 (ME-SFI [ME] control unit).
M16/6r1 (Throttle valve actual value potentiometer):Sliding contact 1

- (N3/10) 2.Measure resistance with multimeter between sockets 1 and 2.3 (N3/10)
- Slowly operate throttle flap by hand up to full load.
Specified values

- Idle speed[290...890]ohms
- Full load[920...1700]ohms
M16/6r1 (Throttle valve actual value potentiometer):Sliding contact 2

- (N3/10) 2.Measure resistance with multimeter between sockets 1 and 2.4 (N3/10)
- Slowly operate throttle flap by hand up to full load.
Specified values

- Idle speed[920...1700]ohms
- Full load[290...890]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.
- 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

2. Preconditions for test B17/8 (Charge air temperature sensor)
Status of relevant actual value:
- B17/8 (Charge air temperature sensor):Warning! Communication with ECU required.
Question

- Is the temperature of component B17/8 (Charge air temperature sensor) higher than 70° C?(158° F)

YES

Test 2.1: Check component B17/8 (Charge air temperature sensor).

Test 2.2: Check component M44 (charge air cooler circulation pump).

Test 2.3: Bleed low temperature coolant circuit of charge air cooler.

2.1. Check component B17/8 (Charge air temperature sensor).

Test 2.1.1: Check component B17/8 (Charge air temperature sensor) using actual value.

Test 2.1.2: Check internal resistance of component B17/8 (Charge air temperature sensor).

Test 2.1.3: Check low-temperature circuit.

2.1.1. Check component B17/8 (Charge air temperature sensor) using actual value.
Test sequence

- Switch on ignition.
Status of relevant actual value:
- B17/8 (Charge air temperature sensor):Warning! Communication with ECU required.
Specified value

- If the connection is unplugged at component B17/8 (Charge air temperature sensor), the value is approx. -40° C.
- Bridge pin 1 in pin 2 at the unplugged connection of component B17/8 (Charge air temperature sensor).Value may be within the range from 140° C to 170° C.
Question

- Is the actual value o.k.?

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

- Air in low-temperature circuit
- Check low-temperature circuit.

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

- Check lines from component B17/8 (Charge air temperature sensor) to component N3/10 (ME-SFI [ME] control unit).
End of test

2.1.2. Check internal resistance of component B17/8 (Charge air temperature sensor).
Test prerequisite

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

- Switch off ignition.
- Measure resistance with multimeter between pins (B17/8) 1 and (B17/8) 2
Specified values

- Resistor(20° C): [5763...6370]ohms
- Resistor(30° C): [3792...4191]ohms
- Resistor(40° C): [2473...2733]ohms
- Resistor(50° C): [1679...1856]ohms
- Resistor(60° C): [1165...1288]ohms
- Resistor(70° C): [822...909]ohms
- Resistor(80° C): [591...654]ohms
- Resistor(100° C): [321...355]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

- B17/8 (Charge air temperature sensor)
End of test

2.1.3. Check low-temperature circuit.
Information

- The low temperature coolant circuit cap may only be opened when the low temperature circuit is cold (ambient temperature).To cool the low temperature circuit quickly, detach component N10/2kQ (Circulation pump relay) and link circuits 30 and 87.At the same time, actuate the electric suction fan via DAS.
Continue to test with button F2

Note

- WIS is not available on this system.
- It is not possible to display the requested WIS document [ ar2000p1145h ].
- You can start WIS on another system and display the WIS document by entering the document number [ ar2000p1145h ] in the 'Contents' field.

2.1.3. No further information available.

2.2. Check component M44 (charge air cooler circulation pump).

Test 2.2.1: Check low-temperature circuit.

Test 2.2.2: Check component M44 (charge air cooler circulation pump) by means of actuation.

Test 2.2.3: Test current consumption of component M44 (charge air cooler circulation pump).

2.2.1. Check low-temperature circuit.
Information

- The low temperature coolant circuit cap may only be opened when the low temperature circuit is cold (ambient temperature).To cool the low temperature circuit quickly, detach component N10/2kQ (Circulation pump relay) and link circuits 30 and 87.At the same time, actuate the electric suction fan via DAS.
Continue to test with button F2

Warning!Communication with ECU required.

2.2.3. Test current consumption of component M44 (charge air cooler circulation pump).
Test prerequisite

- The actuation was not okay.
Test sequence

- Check fuse N10/2f116 (Fuse 116).
Question

- Is fuse N10/2f116 (Fuse 116) OK?

YES
Test prerequisite

- Component M44 (charge air cooler circulation pump) does not run.
Test sequence

- Switch off ignition.
- Detach component N10/2kQ (Circulation pump relay).
- Insert bridge for actuating component M44 (charge air cooler circulation pump).Bridge pin 3 and pin 5.(See fig.2)
- Use fuse cable for bridge.
- Measurement with multimeter
- Remove fuse N10/2f116 (Fuse 116).
- Measure direct current with multimeter between sockets (N10/2f116) 1 and (N10/2f116) 2
- Switch on ignition.
Component M44 (charge air cooler circulation pump) runs.Specified value

- Amperage 3.0...5.0 A
Question

- Is the measurement value OK?

YES
The measurement value is OK.Possible cause and remedy

- N10/2kQ (Circulation pump relay)
End of test

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

- Line from component N10/2f116 (Fuse 116) to component M44 (charge air cooler circulation pump)
- M44 (charge air cooler circulation pump)
- Check low-temperature circuit.
End of test

NO
The fuse is not o.k.Possible cause and remedy

- Test cable N10/2f116 (Fuse 116) to M44 (charge air cooler circulation pump) for Short circuit to ground.
- Visually inspect cable, repair or replace if necessary.
- M44 (charge air cooler circulation pump)
End of test

2.3. Bleed low temperature coolant circuit of charge air cooler.
Note

- WIS is not available on this system.
- It is not possible to display the requested WIS document ar2000p1145h.
- You can start WIS on another system and display the WIS document by entering the document number ar2000p1145h in the 'Contents' field.
Information

- The low temperature coolant circuit cap may only be opened when the low temperature circuit is cold (ambient temperature).To cool the low temperature circuit quickly, detach component N10/2kQ (Circulation pump relay) and link circuits 30 and 87.At the same time, actuate the electric suction fan via DAS.

NO

Test 2.1: Check component B17/8 (Charge air temperature sensor).

2.1. Check component B17/8 (Charge air temperature sensor).

Test 2.1.1: Check component B17/8 (Charge air temperature sensor) using actual value.

Test 2.1.2: Check internal resistance of component B17/8 (Charge air temperature sensor).

Test 2.1.3: Check low-temperature circuit.

2.1.1. Check component B17/8 (Charge air temperature sensor) using actual value.
Test sequence

- Switch on ignition.
Status of relevant actual value:
- B17/8 (Charge air temperature sensor):Warning! Communication with ECU required.
Specified value

- If the connection is unplugged at component B17/8 (Charge air temperature sensor), the value is approx. -40° C.
- Bridge pin 1 in pin 2 at the unplugged connection of component B17/8 (Charge air temperature sensor).Value may be within the range from 140° C to 170° C.
Question

- Is the actual value o.k.?

Note

- WIS is not available on this system.
- It is not possible to display the requested WIS document [ ar2000p1145h ].
- You can start WIS on another system and display the WIS document by entering the document number [ ar2000p1145h ] in the 'Contents' field.

2.1.3. No further information available.

3. The load limit is active.

Test 3.1: Compare test values of pressure sensor with one another.

Test 3.2: Test values of charge pressure control

3.1. Compare test values of pressure sensor with one another.
Warning!Communication with ECU required.

3.2. Test values of charge pressure control
Test prerequisite

- Check vehicle on roller dynamometer following continuous testing or during driving.
- Selector lever position'4'
- Transmission mode 'C'
- Gradually increase engine speed to approx. 2500 rpm in full load mode without kickdown, using the service brake to set full load and engine speed.
- Reduce engine speed to 2000 rpm.
- Increase engine speed to 2500 rpm in full load mode without kickdown and hold for 5 s.

Warning!Communication with ECU required.