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With Generic Scan Tool



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-, function of the E-gas system.

Components of Throttle Valve Control Module -J338-:
- Throttle drive (power accelerator actuation) -G186-
- Angle sensor -1- for throttle drive (power accelerator actuation) -G187-
- Angle sensor -2- for throttle drive (power accelerator actuation)-G188-

Recommended special tools and equipment
- V.A.G 1526 portable multimeter or V.A.G 1715 multimeter
- V.A.G 1594 connector test kit
- Wiring diagram

Test requirements







- The respective fuses of Motronic Engine Control Module (ECM) -J220- must be OK.
- Battery voltage must be at least 11.5 volts.
- All electrical consumers like, for example, lights and rear window heating 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.
- Throttle valve must be in Closed Throttle Position (CTP).
- Adjustment of accelerator pedal cable must be OK, checking.
- Coolant temperature must be at least 80 degrees C, Diagnostic mode 1: Check measuring values; PID 5, Coolant temperature. Refer to "Scan Tool Testing/Diagnostic Mode 1: Check Measuring Values".
Diagnostic Mode 1: Check Measuring Values

Function test
- Connect diagnostic tester. Refer to "Scan Tool Connecting/Diagnostic Tester, Connecting".
Diagnostic Tester, Connecting

- 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.

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 obtained:

Check resistance

Vehicles with engine code AEB







- Disconnect 8-pin harness connector from throttle valve control unit.
- Measure resistance of Throttle Position (TP) Actuator between terminals 1 + 2 at connection.
Specified value: 3...200 Ohms

Vehicles with engine code ATW, AUG, AWM
- Connect test box to control module wiring harness, connect test box for wiring test. Engine Control Module (ECM) is not connected. Refer to "Scan Tool Connecting/Test Box, Connecting For Wiring Test".
Test Box, Connecting For Wiring Test

- Measure resistance of throttle valve drive between test box sockets 117 +118
Specified value: 1...5 Ohms

Continuation for all vehicles
If specified value is obtained:
- Check voltage supply of throttle valve control module and wiring to control module.

If no malfunctions are detected:
- Replace Throttle Valve Control Module -J338-.
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Refer to "Monitors, Trips and/or Drive Cycle/Readiness Code, Generating".
Monitors, Trips, Drive Cycles and Readiness Codes

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-.
Testing and Inspection

If voltage supply and wires are OK:
- Replace Motronic Engine Control Module (ECM) -J220-.

Checking voltage supply and wiring to control module

Vehicles with engine code AEB







- Disconnect 8-pin harness connector from throttle valve control unit.
- Connect multimeter to connector terminals 4 + 7 for voltage measurement.
- Switch ignition on. Specified value: at least 4.5 V
- Switch ignition off.
- Connect multimeter to connector terminals 3 + 7 for voltage measurement.
- Switch ignition on. Specified value: at least 9 V
- Switch ignition off.
- Connect test box to control module wiring harness, connect test box for wiring test. Engine Control Module (ECM) is not connected. Refer to "Scan Tool Connecting/Test Box, Connecting For Wiring Test".
Test Box, Connecting For Wiring Test







- Check for open circuits in wires between test box and connector according to wiring diagram.
Terminal 1 + socket 66
Terminal 2 + socket 59
Terminal 3 + socket 69
Terminal 4 + socket 62
Terminal 5 + socket 75
Terminal 7 + socket 67
Terminal 8 + socket 74
Wire resistance: max: 1.5 Ohms
- Also check wires for short circuit to each other.
Specified value: Infinity Ohms

Vehicles with engine code ATW, AUG, AWM







- Disconnect 6-pin connector -2- at the throttle valve control module -1-.







- Connect multimeter to terminals 2 + 6 of connector for voltage measurement.
- Switch ignition on.
Specified value: at least 4.5 V
- Switch ignition off.







- Connect multimeter to terminal 2 of connector and Ground (GND) for voltage measurement.
- Switch ignition on.
Specified value: at least 4.5 V
- Switch ignition off.

If specified values are not obtained:
- Connect test box to control module wiring harness, connect test box for wiring test. Engine Control Module (ECM) is not connected. Refer to "Scan Tool Connecting/Test Box, Connecting For Wiring Test".
Test Box, Connecting For Wiring Test







- Check for open circuits in wires between test box and connector 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
Wire resistance: max: 1.5 Ohms
- Also check wires for short circuit to each other.
- Also check wires for short circuits to B+ or Ground (GND).

Continuation for all vehicles
If no malfunctions are found in wires:
- Check voltage supply of Engine Control Module (ECM).
Control Module Supply Voltage Check

- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Refer to "Monitors, Trips and/or Drive Cycle/Readiness Code, Generating".
Monitors, Trips, Drive Cycles and Readiness Codes
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