Throttle Valve Control Module, Checking

Throttle Valve Control Module, Checking

NOTE:
- Use only gold-plated terminals when servicing terminals in harness connector of throttle valve control module.
- The throttle valve activation occurs via an electric motor (throttle drive) in the throttle valve control module. This is activated by ECM according to specifications of Throttle Position (TP) Sensor -G79- and Accelerator Pedal Position Sensor 2 -G185-.
- Throttle Valve Control Module -J338- 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-

Recommended Special Tools, Workshop Equipment, Testers, Measuring Instruments and Auxiliary Items
- V.A.G 1526 portable multimeter or V.A.G 1715 multimeter.
- Adapter set V. A. G 1594
- Wiring diagram

Test Conditions
- The corresponding fuses of Motronic Engine Control Module (ECM) -J220- must be OK
- Battery voltage must be at least 11.5 V.
- All electrical consumers such as, for example, lights and rear window defroster must be switched off.
- The parking brake must be applied, otherwise the daytime running lights are switched on.
- If the vehicle is equipped with an air conditioning system, this must be switched off.
- The Ground (GND) connections between engine and body must be OK.
- Throttle valve not damaged or contaminated
- Coolant temperature must be at least 80 degrees C, Diagnostic Mode 01 - Read Current System Data Diagnostic mode 1: Check measured values; PID 5, Coolant temperature.

Function Test
- Connect diagnostic tester. Diagnostic Tester, Connecting
- Switch ignition on.
- Under address word 33, select "Diagnostic mode 1: Checking measuring values."
- Select the measuring value "PID 17: Throttle valve position (absolute)."
- Check specified value of throttle valve position (absolute) at idle stop:







- Slowly depress accelerator pedal up to Wide Open Throttle (WOT) stop while observing the percentage display.
- The percentage display must increase uniformly.
- Check specified value of throttle valve position (absolute) at Wide Open Throttle (WOT) stop:







- End diagnosis and switch ignition off.

If the specifications are not obtained:
- Connect test box to ECM wiring harness. Test Box, Connecting For Wiring Test
- The Engine Control Module (ECM) remains disconnected.
- Measure resistance from throttle valve actuator between test box sockets 117 + 118

- specified value: 1 to 5 Ohms

If the specification is not obtained:
- Replace Throttle Valve Control Module -J338-.
- Erase DTC memory of ECM. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Generate Readiness Code

If the specification is obtained:
- Check voltage supply of throttle valve control module and wiring to control module.
- Check accelerator pedal position sensor. Throttle Position Sensor, Checking

If voltage supply and wiring are OK:
- Replace Engine Control Module (ECM).
- Voltage Supply and Wiring to Control Module, Checking
- Disconnect connector at throttle valve control module.







- Connect multimeter to terminals 2 + 6 of connector for voltage measurement.
- Switch ignition on.

- Specification: approx. 5 V

- Switch off ignition.
- Connect multimeter to terminal 2 of connector and Ground for voltage measurement.
- Switch ignition on.

- Specification: approx. 5 V

- Switch off ignition.

If the specifications are not obtained:
- Connect test box to control module wiring harness. Test Box, Connecting For Wiring Test
- The Engine Control Module (ECM) remains disconnected.
- Check wiring between test box and connector for open circuit according to wiring diagram:
- Terminal 1 + Socket 92
- Terminal 2 + Socket 83
- Terminal 3 + Socket 117
- Terminal 4 + Socket 84
- Terminal 5 + Socket 118
- Terminal 6 + Socket 91







- Wiring resistance: max. 1.5 Ohms

- Also check wires for short circuit to each other.
- Also check wires for short circuit to B+ or Ground.

If no fault is detected in the wiring:
- Check ECM voltage supply.
- Erase DTC memory of ECM. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Generate Readiness Code