Throttle Valve Control Module J338, Checking

Throttle Valve Control Module, Checking

NOTE: If the throttle valve control module is replaced, the new control module must without fail be adapted to the engine control module.

On vehicles installed with an automatic transmission the transmission control module must also be adapted:

Special tools and equipment
- VAG 1551 Scan Tool or VAG 1552 with cable VAG 1551/3
- Test box VAG 1598/22
- Hand multimeter VAG 1526 or multimeter VAG 1715
- Adapter set VAG 1594
- Wiring diagram

Test conditions
- Throttle valve not damaged or dirty.
- Throttle cable adjustment OK, checking

Checking idling switch
- Connect VAG 1551 Scan Tool ((VAG 1552). Then switch ignition on and select engine control module using "Address word" 01. (Connecting scan tool and selecting engine control module [1][2][3]Connecting VAG Scan Tool 1551/1552).

Indicated on display

Rapid data transfer HELP
Select function XX

- Press keys 0 and 8 for function "Read Measuring Value Block" and confirm entry with Q key.

Indicated on display

Read Measuring Value Block HELP
Input display group number XXX

- Press keys 0, 5 and 4 for "Display group number 54" and confirm entry with Q key.

Indicated on display: (1 to 4 = Display zones)

Read Measuring Value Block 54 ->
1 2 3 4

- Check operating mode display in display zone 2.
Display: Idling
- Slowly open throttle valve through range of travel to stop. Open valve further, 4th position from left must jump to part throttle
Display: Part throttle

Display constantly remains on one operating condition:

Display Cause
Part throttle Open circuit or short to B+
Idling Short to Ground

Continuation of check when display shows part throttle







- Pull 8-pin connector off throttle valve control module.
- Bridge connector contacts 3+7 with auxiliary cables from VAG 1594 and observe display.

If display jumps to idling:
- Press -> key.
- Press keys 0 and 6 for "End data transfer" function and confirm input with Q key.
- Switch ignition off.
- Replace throttle valve control module -J338-.

If display remains on part throttle:
- Press -> key.
- Press keys 0 and 6 for "End data transfer" function and confirm input with Q key.
- Switch ignition off.
- Check voltage supply of throttle valve control module and wiring to control module.

If the voltage supply and wiring is OK:
- Replace engine control module.

Continuation of check when display constantly shows idling







- Pull 8 pin connector off throttle valve control module.

If display jumps to part throttle:
- Press -> key.
- Press keys 0 and 6 for "End data transfer" function and confirm input with Q key.
- Switch ignition off.
- Replace throttle valve control module -J338-.

If display remains on part throttle:
- Press -> key.
- Press keys 0 and 6 for "End data transfer" function and confirm input with Q key.
- Switch ignition off.
- Check voltage supply of throttle valve control module and wiring to control module.

If the voltage supply and wiring is OK:
- Replace engine control module.

Checking voltage supply and wiring to control module







- Pull 8 pin connector off throttle valve control module.
- Connect multimeter to measure voltage at connector contacts 4+7.
- Switch ignition on.
Specification: min. 4.5 V
- Connect multimeter to measure voltage at connector contacts 3+7.
Specification: at least 9 V
- Switch ignition off.

If the specifications are not attained:







- Connect test box VAG 1598/22 to control module wiring harness.







- Check wiring for open circuit between test box and connector using wiring diagram:
Contact 1 + socket 66
Contact 2 + socket 59
Contact 3 + socket 69
Contact 4 + socket 62
Contact 5 + socket 75
Contact 7 + socket 67
Contact 8 + socket 74
Wire resistance: max. 1.5 Ohm
- Check additional wires for short to one another.
Specification: Infinite Ohm

If no wiring malfunction is detected:
- Check engine control module voltage supply. Voltage Supply For Engine Control Module (ECM), Checking