Throttle Valve Control Module, Checking

NOTE:

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. It is activated by the Engine Control Module (ECM) according to specifications of the two sensors, Throttle Position (TP) Sensor -G79- and Sender -2- for accelerator pedal position -G185- ELECTRONIC ENGINE POWER CONTROL , function of the EPC system.

Components of Throttle Valve Control Module -J338- :

Throttle drive -G186- (power accelerator actuation)
Angle sensor -1- for throttle drive (power accelerator actuation) -G187-
Angle sensor -2- for throttle drive (power accelerator actuation) -G188-

Special tools and workshop equipment required

Multimeter VAG1526 or multimeter VAG1715
Connector test kit VAG1594
Wiring diagram

Test requirements

Fuses in E-box (in plenum chamber, left) must be OK: Refer to SYSTEM WIRING DIAGRAM

Fig 1: Identifying Fuses In E-Box (In Plenum Chamber, Left)
Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
Battery voltage must be at least 11.5 volts.
All electrical consumers such as, for example, 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 20° C, 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:

PID		Diagnostic text		Specified value:
17:		Throttle valve position (absolute)
		Idle stop		3.0 to 16.0%

-- 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:

PID		Diagnostic text		Specified value:
17:		Throttle valve position (absolute)
		Wide Open Throttle (WOT) stop		84.0 to 93.0%

-- End diagnosis and switch ignition off.

If specified values are not obtained:

-- Disconnect the 6-pin connector at the throttle valve control module (arrow).

Fig 2: Disconnecting 6-Pin Connector At Throttle Valve Control Module

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Checking resistance

-- Measure resistance of Throttle drive -G186- (power accelerator actuation) in Throttle Valve Control Module -J338- between terminals 3 + 5

Fig 3: 6-Pin Sensor Connector & Terminals

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Specified value: 1.0 to 5.0 Ω

If specified value is not obtained:

-- Replace Throttle Valve Control Module -J338-, intake manifold, disassembling and assembling.

-- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.

-- Generate readiness code.

If specified value is obtained:

-- Check voltage supply of throttle valve control module and wiring to control module.

-- Check Throttle Position (TP) Sensor -G79- and Sender -2- for accelerator pedal position -G185- THROTTLE POSITION SENSOR, CHECKING .

If voltage supply and wires are OK:

-- Replace Motronic Engine Control Module (ECM) -J220- ENGINE CONTROL MODULE, REPLACING .

Checking voltage supply and wiring

-- Connect multimeter to connector terminals 2 + 6 for voltage measurement.

Fig 4: Checking Voltage Between Terminals 2 & 6 Of 6-Pin Connector

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Switch ignition on.

Specified value: at least 4.5 V

-- Switch ignition off.

If there is no voltage:

-- Connect test box to control module wiring harness, connect test box for wiring test.

-- Check wires between test box and 6-pin connector for open circuit according to wiring diagram:

Fig 5: Identifying 6 Pin Electrical Harness Connector Terminals

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Terminal 1+socket 92

Terminal 2+socket 83

Terminal 3 + socket 117

Terminal 4 + socket 84

Terminal 5 + socket 118

Terminal 6 + socket 91

Wire resistance: max. 1.5 Ω

-- Also check wires for short circuit to each other, to vehicle Ground (GND) and to B+.

Specified value: ∞ Ω

-- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.

-- Generate readiness code.

If no malfunctions are found in wires:

-- Check voltage supply of Engine Control Module (ECM) according to wiring diagram: Refer to SYSTEM WIRING DIAGRAM

-- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.

-- Generate readiness code.