Electronic Throttle Control Module: Testing and Inspection

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.







- Fuses -1, 2, 3, 4 and 7- in protective housing (plenum chamber, left) must be OK.
- 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 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: Check 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 diagnostic and switch ignition off.


If specified values are not obtained:







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

Checking resistance







- Measure resistance of Throttle drive (power accelerator actuation) -G186- in Throttle Valve Control Module -J338- between terminals 3 + 5
Specified value: 1.0...5.0 Ohms

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. 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.

If there is no voltage:

Checking wiring
- 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 circuit to each other, to vehicle Ground (GND) and to B+.
Specified value: infinity Ohms

- 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 no malfunctions are found in wires:
- Check voltage supply of Engine Control Module (ECM) according to wiring diagram:
- 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