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
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 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.
- Coolant temperature must be at least 80 degree C, Diagnostic mode 1: Check measuring values; PID 5, Coolant temperature. Diagnostic Mode 1: Check Measured Values
Function test
- Connect diagnostic tester. 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:
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test
Engine Control Module (ECM) is not connected.
- Measure resistance of throttle valve drive between test box sockets 117 + 118
Specified value: 1...5 Ohm
If specified value is not obtained:
- Replace Throttle Valve Control Module -J338-.
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Readiness Code, Generating
If specified value is obtained:
- Check voltage supply of throttle valve control module and wiring to control module.
- Check Throttle Position (TP) sensor.
If voltage supply and wires are OK:
- Replace Engine Control Module (ECM).
Checking voltage supply and wiring to control module
- Disconnect connector at throttle valve control module.
- Connect multimeter to terminals 2 + 6 of connector for voltage measurement.
- Switch ignition on.
Specified value: about 5 V
- Switch ignition off.
- Connect multimeter to terminal 2 of connector and Ground (GND) for voltage measurement.
- Switch ignition on.
Specified value: about 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. Test Box, Connecting For Wiring Test
Engine Control Module (ECM) is not connected.
- 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 Ohm
- Also check wires for short circuit to each other.
- Also check wires for short circuits to B+ or Ground (GND).
If no malfunctions are found in wires:
- Check voltage supply of Engine Control Module (ECM). Voltage Supply For Engine Control Module (ECM), Checking
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Readiness Code, Generating