Test Chart 1

Throttle Valve Control Module -J338-, Checking

The following components are located in the housing for the throttle valve control module:
- Throttle Drive (for Electronic Power Control (EPC)) -G186-. (This is an electric motor that is activated by the ECM. This electric motor opens the throttle valve against spring pressure.)
- Throttle Drive Angle Sensor 1 (for Electronic Power Control (EPC)) -G187-
- Throttle Drive Angle Sensor 2 (for Electronic Power Control (EPC)) -G188-

NOTE:
- The housing for the throttle valve control module must not be opened.
- The angle sensors are designed as potentiometers (variable resistances). They communicate the position of the throttle valve to the Engine Control Module (ECM) fully independent of each other.







Recommended special tools and equipment
- VAG1526A multimeter
- VAG1594A connector test kit
- VAG1598/31 test box

Test requirements:
- Fuses for engine electronics OK
- Ground (GND) connections at engine and transmission OK
- Battery voltage at least 12.5 V
- Parking brake engaged.
- Vehicles with automatic transmission: Selector lever in position "P" or "N".
- Electrical consumers switched off (radiator fan must NOT run during test).
- A/C switched off.
- Coolant temperature at least 80 degrees C; "PID 05: Coolant temperature". Diagnostic Mode 01 - Read Current System Data

NOTE: Use only gold-plated terminals when servicing terminals in harness connector of throttle valve control module.

Checking function
- Connect diagnostic tester. VAS 5051, Connecting and Select Functions
- Switch ignition on.
- In diagnostic function "33 - OBD", select "Mode 1: Checking measured values."
- Select desired measuring value "PID 17: Throttle valve position (absolute)."
- Specified value: 12 to 16%
- Slowly depress accelerator pedal completely.
- Specified value: The percentage display must increase uniformly
- Hold accelerator pedal fully depressed; in vehicles with automatic transmission, do not depress beyond the kickdown point when doing this.
- Specified value: 84 to 88%
- Switch ignition off.

If specified values are not obtained:
- Check voltage supply and wire connections of throttle valve control module. Pay particular attention to harness connectors that could be loose or corroded.
- Check Throttle Position (TP) sensor. Testing and Inspection

Checking voltage supply
- Disconnect electrical harness connector at throttle valve control module.
- Switch ignition on.







- Connect multimeter for voltage measurement as follows:

Harness connector Terminal Specified value
2 + Ground (GND) about 5 V
2 + 6 about 5 V

- Switch ignition off.

If specified values are not obtained:

Checking wire connections
- Connect test box to wiring harness of Engine Control Module (ECM); ECM is not connected.







- Check the following wire connections for open circuit according to wiring diagram:

Harness connector Terminal Test box Socket
1 92
2 83
3 117
4 84
5 118
6 91

- Specified value: Wire resistance max 1.5 Ohms
- Check wires for short circuit to each other as well as to B+ and Ground (GND).
- Specified value: Infinity Ohm (no continuity)
- If necessary, repair wire connection.

If no malfunction is detected in wiring and if voltage supply was OK:
- Replace throttle valve control module.
- After replacing throttle valve control module, it must be adapted. For this purpose switch on ignition for at least 30 seconds without starting engine or depressing accelerator pedal.
- Switch ignition off.
- Engine Control Module (ECM) now requires approx. 3 seconds to store the learned value. At this time, the ignition must not be switched on again

Final procedures
1. Check DTC memory. Diagnostic Mode 03 - Read DTC Memory
2. If necessary, erase DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If DTC memory was erased, generate readiness code.

- End diagnosis and switch ignition off.