Throttle Valve Control Module, Checking

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements 

• The Motronic Engine Control Module (ECM) - J220- fuses OK.
  Fig 1: Fuses On E-Box In Engine Compartment, Left Side

  Courtesy of AUDI OF AMERICA, LLC
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position "P" or "N".
• A/C switched off.
• Ground (GND) connections between engine/transmission/chassis OK.
• Throttle valve must not be damaged or dirty.
• Coolant Temperature at least 80° C.

Function 

Throttle valve operation occurs by an electric motor (Throttle Drive (for Electronic Power Control (EPC)) -G186-) in the Throttle Valve Control Module - J338-. It is operated by the Motronic Engine Control Module (ECM) -J220- and the Throttle Position (TP) Sensor -G79- /Accelerator Pedal Position Sensor 2 -G185-.

The Throttle Valve Control Module -J338- is made up of the following components:

• Throttle Drive (for Electronic Power Control (EPC)) -G186-
• Throttle Drive Angle Sensor 1 (for Electronic Power Control (EPC)) -G187-
• Throttle Drive Angle Sensor 2 (for Electronic Power Control (EPC)) -G188-

The Throttle Valve Control Module -J338- cannot be serviced separately and must be serviced as a unit.

Test procedure 

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK 

Start diagnosis 

-- Connect the scan tool.

-- Switch ignition on.

-- Using the scan tool, check the throttle valve position (absolute) at idle stop:

Diagnostic text		Specified value
Throttle valve position (absolute)
Idle stop		3.0 to 25.0%

-- Slowly depress the accelerator pedal to Wide Open Throttle (WOT) stop while observing the percentage display. The percentage display must increase uniformly.

-- Using the scan tool, check the throttle valve position (absolute) at Wide Open Throttle (WOT) stop:

Diagnostic text		Specified value
Throttle valve position (absolute)
Wide Open Throttle (WOT) stop		84.0 to 97.0%

-- End diagnosis and switch ignition off.

If the specified values are not obtained:

-- Remove the Throttle Valve Control Module -J338 - far enough so that the electrical connector terminals are reached.

-- Disconnect the Throttle Valve Control Module -J338- electrical harness connector -arrow-.

Checking resistance 

-- Using a Multimeter, check the Throttle Drive (for Electronic Power Control (EPC)) -G186- at the Throttle Valve Control Module -J338- terminals 3 to 5 for resistance.

Specified value: 1.0 to 5.0 Ω (at 20 °C)

If the specification was not obtained:

-- Replace the Throttle Valve Control Module - J338-. Refer to Repair information.

If the specification was obtained:

-- Check the voltage supply of the Throttle Valve Control Module -J338- to the Motronic Engine Control Module (ECM) -J220-.

-- THROTTLE POSITION SENSOR/ACCELERATOR PEDAL POSITION SENSOR 2, CHECKING .

Checking voltage supply and wiring 

-- Switch the ignition on.

-- Using a Multimeter --, check the Throttle Drive (for Electronic Power Control (EPC)) -G186- at the Throttle Valve Control Module -J338- electrical harness connector terminals 2 to 6 for voltage.

Specified value: at least 4.5 V

-- Switch the ignition off.

If the specification was not obtained:

Checking wiring 

If the manufacturers test box is being used. Perform the following step.

-- Install the test box. Refer to Repair information.

If the manufacturers test box is not being used. Perform the following step.

-- Remove the Motronic Engine Control Module (ECM) -J220-. Refer to Repair information.

-- Using a Multimeter --, check the Throttle Drive (for Electronic Power Control (EPC)) -G186- at Throttle Valve Control Module -J338- electrical harness connector terminals to the Motronic Engine Control Module (ECM) -J220- electrical harness connector T60 terminals for an open circuit according to the wiring diagram.

Throttle Valve Control Module -J338- electrical harness connector terminals	Motronic Engine Control Module (ECM) -J220- electrical connector T60 terminals or test box socket
1	12
2	28
3	30
4	27
5	15
6	29

Specified value: 1.5 Ω max.

If the specification is not obtained:

-- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).

-- If necessary, repair the faulty wiring connection.

-- Check the electrical harness connector for damage, corrosion, lose or broken terminals.

If no malfunction is detected in the wiring and if the voltage supply was not OK:

-- Replace the Motronic Engine Control Module (ECM) -J220-. Refer to Repair information.

Final procedures 

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .

-- End of diagnosis.