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Home >> Mercedes Benz >> 2007 >> SL 600 (230.477) V12-5.5L Turbo (275.954) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Manufacturer Code Charts >> 202B

202B


Diagnosis of idle speed control (P0505, P0506, P0507)


Possible cause:

- B37 (Accelerator pedal sensor)
- M16/6 (Throttle valve actuator)
Affected functions:

- Engine output

-------------------------------------------------

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

Test 2: Check component B37 (Accelerator pedal sensor).

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. Check component B37 (Accelerator pedal sensor).

Test 2.1: Check component B37 (Accelerator pedal sensor) using actual value.

Test 2.2: Check power supply of component B37 (Accelerator pedal sensor).

2.1. Check component B37 (Accelerator pedal sensor) using actual value.
Test prerequisites

- Relevant fault code exists or there is a complaint.
Test sequence

- Switch on ignition.
Status of the relevant actual values:
- B37 (Accelerator pedal sensor) Signal 1:Warning! Communication with ECU required.
- B37 (Accelerator pedal sensor) Signal 2:Warning! Communication with ECU required.
Specified values

- Accelerator pedal position:Idle speed
- B37 (Accelerator pedal sensor)Signal 1):[0.2...0.5] V
- B37 (Accelerator pedal sensor)Signal 2):[0.1...0.4] V

- Accelerator pedal position:Kickdown
- B37 (Accelerator pedal sensor)Signal 1:[4.1...4.7] V
- B37 (Accelerator pedal sensor)Signal 2:[2.0...2.4] V
Question

- Are the actual values o.k.?


YES
The actual values are okay.Possible cause and remedy

- This test did not produce any clear result.
- Conduct further checks on component B37 (Accelerator pedal sensor).


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

- Check power supply of component B37 (Accelerator pedal sensor).
- Check lines from component N3/10 (ME-SFI [ME] control unit) to component B37 (Accelerator pedal sensor).
- B37 (Accelerator pedal sensor)


2.1. No further information available.

2.2. Check power supply of component B37 (Accelerator pedal sensor).
Test prerequisite

- The actual value is not o.k.
- 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 (4.16) 101 and (4.04) 89 of the 126-pole socket box tester.
- Measure direct voltage with multimeter between sockets (4.17) 102 and (4.04) 89 of the 126-pole socket box tester.
- Switch on ignition.
Specified value

- Voltage[4.75...5.25] V
Question

- Are the measurement values OK?


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

- Signal lines
- B37 (Accelerator pedal sensor)
End of test

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

- Cable for voltage supply
- N3/10 (ME-SFI [ME] control unit)
End of test

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