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Testing ignition system > < Checking Hall sender -G40

A3 Mk1

Motronic injection and ignition system (4-cyl. turbo)
Checking ignition system
Checking misfire detection

Special tools and workshop equipment required
 
W00-0706
  • ◆ VAS 5051 with VAS 5051/1

Test sequence

  • ‒ Connect vehicle diagnostic, testing and information system VAS 5051 and select vehicle system "01 -Engine electronics" in the selection. For this purpose, the engine must be running at idling speed.
 
A01-0122

→ Display on VAS 5051:

  • ‒ Under -1- select the diagnostic function "08 - Read measured value block".
 
A01-0130

→ Display on VAS 5051:

  •     1 -    Enter display group
    max. input value = 255
  • ‒ Enter "014" for "display group number 014" in zone -2- and confirm the entry by pressing the Q key.
 
A01-0139

→ Display on VAS 5051:

  • ‒ Check the misfire detection in display zones -3- and -4-.

Display zones

1

2

3

4

Display group 014: Misfire detection

Display

xxx rpm

xxx %

xxx

---

Display

Engine speed

Load

Total misfires

Misfire detection

Range

activated
blocked

Specified value

xxxx rpm

10...25 %

0

activated

Note:

If nominal value is exceeded: Checking misfire of the individual cylinders => Page 28-56.

If misfires are to be expected due to the operation (e.g. running warm, push switch off) the misfire recognition is blocked.

If specified value is attained:

  • ‒ Exit the function "08 - Read measured value block" by pressing the ◂ key.

If specified value is not attained:

  • ‒ Select the s key in order to change to display group 015.

Checking misfire recognition of the individual cylinder
 
A01-0139

→ Display on VAS 5051:

  • ‒ Check detection of misfires in display zones -1- to -4-.

Display zones

1

2

3

4

Display group 015: Misfire detection of cylinders 1, 2 and 3

Display

xxx

xxx

xxx

---

Display

Number of misfires in cylinder 1

Number of misfires in cylinder 2

Number of misfires in cylinder 3

Misfire detection

Range

activated
blocked

Specified value

0

0

0

activated

Note:

If nominal value is exceeded: Evaluation => Page 28-58

---
 
A01-0139
  • ‒ Select the s -key in order to change to display group 016.

→ Display on VAS 5051:

  • ‒ Check the misfire detection in display zones -1- and -4-.

Display zones

1

2

3

4

Display group 016: Misfire recognition of cylinder 4.

Display

xxx

---

Display

Number of misfires in cylinder 4

Misfire detection

Range

activated
blocked

Specified value

0

activated

Note:

If nominal value is exceeded: Evaluation => Page 28-58

---
  • ‒ Exit the function "08 - Read measured value block" by pressing the ◂ key.

Evaluating display groups 014, 015 and 016:

Qty.
Misfire-
detection

Possible causes of fault

Fault remedy

Higher than 0

- Defective spark plug
- Defective spark plug connector
- Ignition coil or output stage defective

- Test spark plugs and ignition wiring
Ignition coils with output stages
Checking => Page 28-4

- Injector defective

- Check injectors
.

Testing ignition system > < Checking Hall sender -G40