With Generic Scan Tool

Throttle valve control module, checking

80-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 throttle valve control module is is not supplied with power, (e.g. connector disconnected) the throttle valve moves to a preset position, resulting in an increased idle speed of 1200 RPM to 1300 RPM with engine at operating temperature.

If only the throttle drive (power accelerator actuation) -G186- is not supplied with power, the throttle valve also moves to the preset position (emergency running gap), however, since Closed Throttle Position (CTP) Switch -F60- can still be recognized, a nominal idle speed of approx. 900 RPM is obtained via retarding the ignition timing.

If the Engine Control Module (ECM) detects a malfunction at Angle sensor -1- for throttle drive (power accelerator actuation) -G187-, the Engine Control Module (ECM) interrupts the power supply to the Throttle drive (power accelerator actuation) -G186-. When this occurs, the throttle valve moves into the preset mechanical position (emergency running gap) in order to increase the idle speed.

Recommended special tools and equipment
- VAG 1526 multimeter or VAG 1715 multimeter
- VAG 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.

Checking voltage supply and wiring to control module






- 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.

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 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

If no wiring faults are found:

- Check voltage supply of Engine Control Module (ECM).

- Erase DTC memory of Engine Control Module (ECM).

- Generate readiness code.