With Generic Scan Tool
Throttle valve control module, checking
Vehicles with engine code AHA (80-pin Engine Control Module -ECM-)
Vehicles with engine code ATQ (121-pin Engine Control Module -ECM-).
Function
Components of Throttle Valve Control Module -J338-:
Throttle drive (power accelerator actuation) -G186-, Angle sensor -1- for throttle drive (power accelerator actuation) -G187-, Throttle Position (TP) Sensor -G69- and Closed Throttle Position (CTP) Switch -F60-.
If the complete throttle valve control module is current-less (e.g. connector disconnected) the throttle valve moves into a particular, specified mechanical position, which signals an increased idle speed of 1200 RPM to 1300 RPM with an engine at operating temperature.
If only the Throttle drive (power accelerator actuation) -G186- is current-less, the throttle valve also moves into the specified mechanical position (emergency running gap), however, since Closed Throttle Position (CTP) Switch - F60- can still be recognized, an "almost normal" idle speed of approx. 900 RPM is reached via the respective ignition angle retardation.
If the Engine Control Module (ECM) detects a malfunction at Angle sensor -1- for throttle drive (power accelerator actuation) -G187-, Throttle drive (power accelerator actuation) -G186- is switched current-less by the Engine Control Module (ECM) and the throttle valve moves into the specified mechanical position (emergency running gap) again.
Recommended special tools and equipment
- V.A.G 1526 multimeter or V.A.G 1715 multimeter
- V.A.G 1594 Connector test set
- 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. Diagnostic Mode 1: Check Measuring Values
Checking voltage supply and wiring to control module
- Disconnect 8-pin connector -1- from throttle valve control module -2-.
- 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 9.0 V
- Switch ignition off.
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test
- Check wires between test box and 8-pin connector for open circuit 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 circuits to each other, to vehicle Ground (GND) and to B+.
Specified value: Infinity Ohms
If no malfunctions are found in wires:
- Check voltage supply of Engine Control Module (ECM). With Generic Scan Tool
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
Vehicles with engine code ATQ (121-pin Engine Control Module -ECM-)
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 multimeter or V.A.G 1715 multimeter
- V.A.G 1594 Connector test set
- 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 degrees C, Diagnostic mode 1: Check measuring values; PID 5, Coolant temperature. Diagnostic Mode 1: Check Measuring Values
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 specified values are not obtained:
- Disconnect 6-pin connector -2- at the throttle valve control module -1-.
Check resistance
- Measure resistance of Throttle drive (power accelerator actuation) -G186- in Throttle Valve Control Module -J338- between terminals 3 + 5
Specified value: 3.0 to 200.0 Ohms
If specified value is not obtained:
- Replace Throttle Valve Control Module -J338-, Throttle valve control module, removing and installing.
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. 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
- Connect multimeter to connector terminals 2 + 6 for voltage measurement.
- Switch ignition on.
Specified value: at least 4.5 V
- Switch ignition off.
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test
- Check wires between test box and 6-pin 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
Wire resistance: max: 1.5 Ohms
- Also check wires for short circuits to each other, to vehicle Ground (GND) and to B+.
Specified value: Infinity Ohms
If no malfunctions are found in wires:
- Check voltage supply of Engine Control Module (ECM). With Generic Scan Tool
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes