Throttle Valve Control Module -J338-, Checking
Throttle Valve Control Module -J338-, Checking
The following components are located in the housing for the throttle valve control module:
- Throttle drive (power accelerator actuation) -G186-. (This is an electric motor that is activated by the ECM. This electric motor opens the throttle valve against spring pressure.)
- Angle sensor -1- for throttle drive (power accelerator actuation) -G187-
- Angle sensor -2- for throttle drive (power accelerator actuation) -G188-
NOTE:
- The housing for the throttle valve control module must not be opened.
- The angle sensors are designed as potentiometers (variable resistances). They communicate the position of the throttle valve to the Engine Control Module (ECM) fully independent of each other.
Recommended special tools and equipment
- V.A.G 1526A multimeter
- V.A.G 1594A connector test kit
- V.A.G 1598/31 test box
Test requirements:
- Fuses for engine electronics OK
- Ground (GND) connections at engine and transmission OK
- Battery voltage at least 12.5 V
- Parking brake engaged.
- Selector lever of automatic transmission in position "P" or "N".
- Electrical consumers switched off (radiator fan must NOT run during test).
- A/C switched off.
- Coolant temperature at least 80 degrees C see "Mode 1: Check measuring values "; "PID 05: Coolant temperature". Mode 1: Check Measured Values
NOTE: Use only gold-plated terminals when servicing terminals in harness connector of throttle valve control module.
Checking function
- Connect diagnostic tester.
- Switch ignition on.
- In diagnostic function "33 - OBD", select "Mode 1: Checking measured values."
- Select the desired measuring value "PID 17: Throttle valve position (absolute)."
- Specified value: 12 to 16%
- Slowly depress accelerator pedal completely.
- Specified value: The percentage display must increase uniformly
- Hold accelerator pedal fully depressed; in vehicles with automatic transmission, do not depress beyond the kickdown point when doing this.
- Specified value: 84 to 88%
- Switch ignition off.
If specified values are not obtained:
- Check voltage supply and wire connections of throttle valve control module, Pay particular attention to harness connectors that could be loose or corroded.
- Check Throttle Position (TP) sensor. Throttle Position (TP) Sensor, Checking
Checking voltage supply
- Remove rear engine cover -arrows-.
- Disconnect electrical harness connector -1- at Throttle Valve Control Module -J338-.
NOTE: Disregard items -2- and -3-.
- Switch ignition on.
- Connect multimeter for voltage measurement as follows.
Harness connector Terminal Specified value
2 + Ground(GND) about 5 V
2 + 6 about 5 V
- Switch ignition off.
If specified values are not obtained:
Checking wire connections
- Connect test box to wiring harness of Engine Control Module (ECM), ECM is not connected. Test Box, Connecting For Wiring and Component Test
- Check the following wire connections for open circuit according to wiring diagram:
Harness connector Terminal Test box Socket
1 92
2 83
3 117
4 84
5 118
6 91
Specified value: Wire resistance max 1.5 Ohms
- Check wires for short circuit to each other as well as to B+ and Ground (GND).
- Specified value: Infinite Ohms (no continuity)
- If necessary, repair wire connection.
If no malfunction is detected in the wiring and if the voltage supply was OK:
- Replace throttle valve control module
- After replacing the throttle valve control module, it must be adapted. For this purpose switch on ignition for at least 30 seconds without starting engine or depressing accelerator pedal.
- Switch ignition off.
- Engine Control Module (ECM) now requires approx. 3 seconds to store the learned value. At this time, the ignition must not be switched on again
Assembly is performed in the reverse order of removal, note the following:
Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check DTC memory see "Mode 3: Check DTC memory". Mode 3: Check DTC Memory
2. If necessary, erase DTC memory see "Mode 4: Reset/erase diagnostic data". Mode 4: Reset/Erase Diagnostic Data
3. Generate readiness code. Readiness Code, Generating
- End diagnosis and switch ignition off.