With Manufacturer's Scan Tool
Engine Control Module (ECM) Voltage Supply Checking
Special tools and equipment
- Scan tool VAG 1551 or vehicle system tester V.A.G 1552 with cable VAG 1551/3B
- Test box V.A.G 1598/31
- Hand multimeter V.A.G 1526 or multimeter VAG 1715
- Adapter set V.A.G 1594
- Wiring diagram
Check conditions
- All Fuses must be OK
- The battery voltage must be at least 11.5 V
- Alternator OK
- All electrical consumers, e.g. lights and rear window heating must be switched off
- If the vehicle is equipped with an air conditioner, this must be switched off
- Selector lever must be in "P" or "N" position on vehicles with an automatic transmission
Test sequence
- Connect scan tool VAG 1551 (V.A.G 1552). Start engine and select "Address word" 01 of Engine Control Module (ECM). Engine must be running at idle speed.
Connecting scan tool and selecting Engine Control Module (ECM). Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/VAG1551 Scan Tool" Testing and Inspection
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons 0 and 8 for function "Read Measuring Value Block" and confirm entry with Q button.
Indicated on display
Read Measuring Value Block
Input display group number XXX
- Press buttons 0, 0 and 4 for "Display group number 4" and confirm entry with Q button.
Indicated on display (1-4 = Display zones)
Read Measuring Value Block 4 ->
1 2 3 4
- Read supply voltage for the Engine Control Module (ECM) in display zone 2.
Specification: At least 11.5 V
- Press -> button.
- Press buttons 0 and 6 for function 11End output" and confirm entry with Q button.
- Switch ignition off.
If the specification is not attained:
- Remove inner plenum chamber cover, left:
- Connect test box V.A.G 1598/31 to control module wiring harness. The engine control module is not connected by this action.
Checking voltage supply terminal 30
- Measure supply voltage between test box sockets 1 + 62 and 2 + 62 using multimeter and adapter cables from V.A.G 1594:
Specification: min. 11.5 V
If the specification is not attained:
- Check wiring connections to relay plate according to wiring diagram.
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Refer to "Displaying and Reading Trouble Codes/With Manufacturers Scan Tool/DTC Memory Checking and Erasing" Testing and Inspection
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again.
Refer to "Monitors, Trips and/or Drive Cycle/Readiness Code, Displaying" Testing and Inspection
Refer to "Monitors, Trips and/or Drive Cycle/Readiness Code, Generating" Testing and Inspection
Checking voltage supply terminal 15
- Measure supply voltage between test box sockets 1 + 3 and 2 + 3 using multimeter and cables from V.A.G 1594.
- Switch ignition on.
Specification: mm. 11.5 V
- Switch ignition off.
If the specification is not attained:
- Check wiring connections to relay plate according to wiring diagram.
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Refer to "Displaying and Reading Trouble Codes/With Manufacturers Scan Tool/DTC Memory Checking and Erasing" Testing and Inspection
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again.
Refer to "Monitors, Trips and/or Drive Cycle/Readiness Code, Displaying" Testing and Inspection
Refer to "Monitors, Trips and/or Drive Cycle/Readiness Code, Generating" Testing and Inspection