Throttle Valve Control Module, Checking

Throttle Valve Control Module, Checking

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

Function

The throttle valve activation occurs via an electric motor (throttle drive) in the throttle valve control module. This is operated by Engine Control Module (ECM) according to specifications from both Throttle Position (TP) Sensor (G79) and Accelerator Pedal Position Sensor 2 (G185).

Components of Throttle Valve Control Module (J338):

• 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)

Special tools, testers and auxiliary items required

• Multimeter (VAG1526) or Multimeter (VAG1715)

• connector test kit (VAG1594)

• Wiring diagram

Test Prerequisites

• The respective fuses of Engine Control Module (ECM) (J623) must be OK:

• Battery voltage must be at least 11.5 Volts.

• All electrical consumers such as, lights and rear window defroster must be switched off.

• Parking brake must be engaged or else daylight driving lights will be switched on.

• If vehicle is equipped with an A/C system, it must be switched off.

• Ground (GND) connections between engine and chassis must be OK.

• Throttle valve must not be damaged or dirty.

• Coolant temperature must be at least 80 °C => [ Diagnostic Mode 01 - Read Current System Data ] Diagnostic Modes 01 - 09, Diagnostic mode 1: Check measured values; PID 5, Coolant temperature.

Function Test

- Connect diagnostic tester.

- Switch ignition on.

- Under address word 33, select "Diagnostic mode 1: Checking measured 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.

Specified value: 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 specified values are not reached, check voltage supply.

Voltage Supply, Checking

- Pull connector off throttle valve control module.

- Switch ignition on.

- Connect multimeter to the following connector terminals for voltage measurement:









If specified values are obtained, also check signal wires and activation wires of throttle valve control module.

If specified values are not obtained:

Check wire connections from Engine Control Module (ECM) to throttle valve control module.

Wire Connections, Checking

- Pull connector off throttle valve control module.





- Connect test box (VAG1598/31) to wiring harness of Engine Control Module (ECM) .

The following wire connections must be checked for short circuit to B+, Ground (GND) and for open circuit





- Repair open circuit in wiring or short circuit if necessary.

If no malfunctions are found in wires:

- Replace throttle valve control module.

- Read readiness code => [ Readiness Code, Reading ] Monitors, Trips, Drive Cycles and Readiness Codes. If DTC memory was erased, readiness code must be generated again => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.