With Manufacturer's Scan Tool
Throttle Valve Control Module, Checking
Components of throttle valve control module (J338): Throttle valve drive (G186), angle sensor 1 for throttle valve drive (G187) and angle sensor 2 for throttle valve drive (G188).
NOTE:
- If the throttle valve control module is replaced, the new control module must without fail be adapted to the Engine Control Module (ECM).
- On vehicles fitted with an automatic transmission the transmission control module must also be adapted:
Special tools and equipment
- Scan tool VAG 1551 or vehicle system tester V.A.G 1552 with cable VAG 1551/3B
- Test box V.A.G 1598/31
- Hand multimeter V.A.G 1526 or multimeter VAG 1715
- Adapter set V.A.G 1594
- Wiring diagram
Test conditions
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Reading Diagnostic Trouble Codes
- Throttle valve not damaged or dirty.
- All electrical consumers, e.g. lights and rear window heating must be switched off.
- If the vehicle is equipped with an air conditioner, this must be switched off.
- The battery voltage must be at least 11.5 V.
- Coolant temperature must be at least 85 °C, see display group 04, display zone 3.
- On vehicles with automatic transmission selector lever in "P" or "N" position
NOTE: Only gold-plated terminals can be used to repair the terminals in the connector for the throttle valve control module.
- Connect scan tool VAG 1551 (V.A.G 1552). Then switch ignition on and select engine control module with "Address word" 01.
Connecting scan tool and selecting engine control module.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons 0 and 8 for function "Read Measuring Value Block" and confirm entry with Q button.
Indicated on display
Read Measuring Value Block
Input display group number XXX
- Press buttons 0, 6 and 2 for "Display group number 62" and confirm entry with Q button.
Indicated on display (1-4 = Display zones)
Read Measuring Value Block 62 ->
1 2 3 4
- Check throttle valve angle of sensor 1 (G187) on idle speed stop in display zone 1.
Specification: 3 to 16 %
- Check throttle valve angle of sensor 2 (G188) on idle speed stop in display zone 2.
Specification: 97 to 82 %
- Depress accelerator slowly until full throttle position and observe angles displayed in display zones 1 and 2:
- The percent display in display zone 1 must rise continuously and evenly. The full tolerance range 3 to 93 % is not always displayed.
- The percent display in display zone 2 must fall continuously and evenly. The full tolerance range 97 to 3 % is not always displayed.
NOTE:
- The reason why the display in display zone 1 rises and the display in display zone 2 falls is because the potentiometers (angle sensors) in the throttle valve control modules run in counter directions.
- The percentage indicated in display zones 1 and 2 must always total approx. 100 %.
- The voltage of angle sensor 1 moves toward 5 volts. (The more the throttle valve is opened the higher the voltage; percentage increases).
- The voltage of angle sensor 2 drops from 5 volts toward 0 volt. (The more the throttle valve is opened the lower the voltage; percentage falls).
If the specifications are obtained:
- Press -> button.
- Press buttons 0 and 6 for function "End output" and confirm entry with Q button.
- Switch ignition off.
If the displays do not indicate as described:
- Press -> button.
- Press buttons 0 and 6 for function "End output" and confirm entry with Q button.
- Switch ignition off.
- Remove inner plenum chamber cover, left:
- Connect test box V.A.G 1598/31 to control module wiring harness. Engine control module is not connected by this action.
- Measure resistance of throttle valve drive between test box sockets 117 + 118
Specification: 1.0. to 5.0 Ohms
If the specification is not obtained:
- Replace throttle valve control module (J338)
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Reading Diagnostic Trouble Codes
- Adapt engine control module to throttle valve control module.
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again. Monitors, Trips, Drive Cycles and Readiness Codes Monitors, Trips, Drive Cycles and Readiness Codes
If the specification is obtained:
- Check voltage supply of throttle valve control module and wiring to control module.
- Check accelerator pedal sensor (E-Gas).
If the voltage supply and wiring is OK:
- Replace Engine Control Module (ECM).
Checking voltage supply and wiring to control module
- Disconnect 6-pin connector off throttle valve control module -arrow-.
- Connect multimeter to measure voltage at terminals 2 and 6.
- switch ignition on.
Specification: min. 4.5 V
- Switch ignition off.
- Connect multimeter to measure voltage at connector terminal 2 and Ground.
- Switch ignition on.
Specification: min. 4.5 V
- Switch ignition off.
If the specifications are not attained:
- Remove inner plenum chamber cover, left:
- Connect test box V.A.G 1598/31 to control module wiring harness. Engine control module is not connected by this action.
- Check wiring for open circuit between test box and connector terminals:
- 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
- Additionally check wires for short to one another.
Specification: Infinity Ohms
- Check wiring additionally for short circuit to battery positive or Ground.
Specification: Infinity Ohms
NOTE: Only gold-plated terminals can be used to repair the terminals in the connector for the throttle valve control module.
If no wiring problem is detected:
- Check Engine Control Module (ECM) voltage supply.