Injektor calibration with VCDS (Articles)

Adjust IMA-ISA values – TDI Injector Calibration with VCDS (Injector Learning)

Whoever works on modern diesel engines will sooner or later come across piezo injectors . These high-precision components are measured and classified in the factory – the so-called IMA (Injector Quantity Adjustment) and ISA values (Injector Voltage Adjustment). They describe the individual injection behavior of each valve.

However, due to manufacturing tolerances, each injector has its own characteristic. The Engine Control Unit (ECU) uses these values together with self-learned correction factors to optimally calculate the pre- and post-injection for each cylinder.

Quote:

Important: IMA-ISA values are dependent on operating life. An injector with 10,000 km will behave differently than one with 70,000 km. The control unit automatically adjusts the learning values during operation. If the IMA-ISA values are changed, these learning values are reset – the control unit assumes that a new injector has been installed.

When should IMA-ISA values be adjusted?

• One or more injectors have been replaced – Note: Only adjust the new valves, not the old ones!
  
• The engine control unit has been replaced.
  
• Do not adjust if none of the components mentioned have been replaced – this also applies to training purposes.

The adjustment code – where can I find it?
The code is directly on the injector. It is usually a 7-digit value .
Exception: 1.2L engines with Delphi injectors – here there is a 20-digit code . This must be converted before entering, as the control unit only understands hexadecimal values.

Conversion table (Code on the injector → converted code)

Code on Injector:	Corresponds to	Modified Code:
0	→	00
1	→	01
2	→	02
3	→	03
4	→	04
5	→	05
6	→	06
7	→	07
8	→	08
9	→	09
A	→	0A
B	→	0B
C	→	0C
D	→	0D
E	→	0E
F	→	0F
G	→	10
H	→	11
J	→	12
K	→	13
L	→	14
M	→	15
N	→	16
P	→	17
R	→	18
S	→	19
T	→	1A
U	→	1B
W	→	1C
X	→	1D
Y	→	1E
Z	→	1F

Example:[/code]

Prerequisites

• The new injectors have been installed, and the IMA-ISA codes are available.
  
• Ignition ON
  
• Engine OFF

Instructions – Adjust IMA-ISA values with VCDS

1. Start VCDS and connect to the vehicle.
   
2. [Select] → 01 – Engine
   
3. [Adaptation – 10]
   
4. Now the channels will appear:
   
   • Channel: Injector 1 correction value
     
   • Channel: Injector 2 correction value
     
   • Channel: Injector 3 correction value
     
   • ... (other cylinders, for a 4-cylinder engine, adjust accordingly up to channel 4)
   
   
5. For each injector to be adjusted, enter the converted value.
   
6. [Test] → [Save] → [Done, Go Back]
   
7. Turn off the ignition, wait for 10 seconds, then turn the ignition back on.
   
8. The values should now be saved. To check, call up the adaptation channels again and verify.

Instructions

• If the code on the new injector is difficult to read, scanning with a QR code (e.g., using the i‑nigma app – works on BB, Android and iOS) is often helpful.
  
• After adjustment, the previous learning values of the control unit are deleted. The vehicle should then be driven for a certain period in normal operation so that the control unit can relearn.
  
• No experiments: Only adjust if the injector or the control unit has been replaced.

If anything is unclear, refer to the official VCDS manual or relevant forums.

See also:
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