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Matching engine electronic control unit to electronic immobilizer > < Replacing engine control unit

Golf Mk3

Diesel direct injection and glow plug system
Replacing, coding and matching engine control unit
Coding engine control unit

There are control units which must not be coded (engine control unit MSA12) and control units which must be coded (engine control unit MSA15).

If the appropriate code for the vehicle is not displayed or if the control unit has been renewed, the control unit must be coded as follows.

Warning!
Always display the the control unit identification first and print out if necessary.
An incorrect coding can have a negative effect on engine, gearbox and emissions.

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

  • ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3

Work sequence

  • ‒ Connect the fault reader V.A.G 1551 (V.A.G 1552). Then switch ignition on and select engine control unit with the "Address word" 01.
    (Connecting fault reader and selecting engine control unit .)

Control unit identification of MSA12
 
→ If the fault reader V.A.G 1551 displays this control unit identification, then the control unit must not be coded (example):
028906021C     1.9 ltr.     R4     EDC SG     D.. ⇒
Coding 0000     WSC0000
  • ◆ There are no zeros in front of the type of gearbox (MG or AG).
  • ◆ The software version begins with a letter.

Externally the MSA12 can be recognised by the plastic housing.

Control unit identification of MSA15
 
→ If the fault reader V.A.G 1551 displays this control unit identification, then the control unit must be coded (example).
028906021DF 1.9l R4 EDC G00SG 0602⇒
Coding 00002     WSC XXXXX
  • ◆ In front of the type of gearbox (MG or AG) are two zeros and possibly also letters.
  • ◆ The software version is made up of a 4 digit number, e.g. 0602 or a capital letter-number combination, e.g. KD02.
  • ◆ The display KDxx means that the engine control unit is an exchange engine control unit. See engine control unit print-out for coding to be entered.

Note:
 
→ The display KDxx means that the engine control unit is an exchange engine control unit. When replacing this engine control unit by a control unit with the same identification, then see engine control unit print-out for coding to be entered, e.g. 00012.
028906021FB 1.9l R4 EDC G00SG KD02
Coding 00012     WSC XXXXX

Externally the MSA15 is recognised by the aluminium housing.

  • ‒ Press ⇒key.
 
→ Indicated on display:
Rapid data transfer     HELP
Select function XX
  • ‒ Press keys 0 and 7 for the function "Code control unit" and confirm entry with Q key.
 
→ Indicated on display:
Coding control unit     Q
Enter code number xxxxx (0-32000)

Coding when replacing a MSA 12 engine control unit with a MSA 15 engine control unit

  • ‒ Code the exchange engine control unit MSA15 according to table.

Example:

Part number of old control unit MSA12:
- 028 906 021 C

Part number of exchange control unit MSA15:
- 028 906 021 FB

Coding of exchange engine control unit MSA15:
- 00011

Control unit MSA12

Exchange control unit MSA15

Coding for exchange control unit MSA 15

028 906 021 C

028 906 021 FB

00011

028 906 021 Q

028 906 021 FB

00012

028 906 021 AH

028 906 021 FG

00011

028 906 021 BP

028 906 021 FJ

00002

028 906 021 BJ

028 906 021 FS

00002

028 906 021 AG

028 906 021 GG

00001

028 906 021 AF

028 906 021 GG

00002

Coding engine control unit MSA 15 (without display "KDxx" in control unit identification)

  • ‒ Enter the appropriate code number for this vehicle and confirm with Q key.

Coding

For vehicles with

00001

Automatic gearbox

00002

Manual gearbox

00003

Four wheel drive
 
→ The fault reader V.A.G 1551 displays the control unit coding, e.g.:
028906021FS 1.9l R4 EDC G00SG 1407     ⇒
Coding 0002     WSC XXXXX
  • ‒ Press ⇒key.
  • ‒ Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.
  • ‒ Switch ignition off and then on again.

Note:

The coding entered will be activated by switching the ignition off and then on again. If after entering the valid code the ignition is not switched off and on again, the fault "Control unit incorrectly coded" in the fault memory cannot be erased.

  • ‒ Erasing fault memory => Page 01-35
  • ‒ Activating cruise control system

=> Current flow diagrams, Electrical fault finding and Fitting locations binder

Matching engine electronic control unit to electronic immobilizer > < Replacing engine control unit