With Manufacturer's Scan Tool
Throttle Valve Control Module -J338- Checking
NOTE:
- Only gold plated terminals may be used to service the terminals in the connector of the throttle valve control module -J338-.
- Components of throttle valve control module -J338-: Throttle drive (power accelerator actuation) -G186-, Angle sensor -1- for throttle drive (power accelerator actuation) -G187- and Angle sensor -2- for throttle drive (power accelerator actuation) -G188-.
- If the throttle valve control module -J338- is replaced, the new control module must be adapted to the Motronic Engine Control Module (ECM) -J220-.
- On vehicles installed with an automatic transmission the transmission control module must also be adapted:
Special tools, workshop equipment, testers, measuring instruments and auxiliary items required
- VAG 1551 Scan tool (or VAG 1552) with VAG 1551/3 adapter cable
NOTE: All functions which could previously be performed with VAG 1551/1552 can also be performed with the VAS 5051.
- VAG 1526 Hand multimeter or VAG 1715 multimeter
- VAG 1594 Adapter set
- VAG 1598/31 Test box
- Electrical Wiring Diagrams
Test prerequisites
- The fuses must be OK.
- The battery voltage must be at least 11.5 V.
- All electrical accessories, e.g. lights and rear window heating must be switched off.
- If the vehicle is equipped with air conditioning, it must be turned off.
- Selector lever must be in position "P" or "N" on vehicles with an automatic transmission.
- Fuel Pump (FP) Relay -J17- must be OK., checking:
- Engine Coolant Temperature (ECT) must be at least 85 degrees C, See display group 1, display zone 2.
- Throttle valve not damaged or contaminated/dirty.
Test sequence
- Connect VAG 1551 Scan tool (or VAG 1552). Then switch ignition on and select Motronic Engine Control Module (ECM) -J220- with the "Address word" 01. ((VAG 1551 and Motronic Engine Control Module (ECM) -J220-, connecting and selecting).
[1][2][3]Connecting VAG 1551 Scan Tool
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- for function "Read measured value (data) block" and confirm entry with -Q- button.
Indicated on display:
Read measured 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 to 4 = display zones)
Read measured value block 62 ->
1 2 3 4
- Check throttle valve angle from sensor 1 -G187- at idling stop in display zone 1
Specification: 3 to 93%
- Check throttle valve angle from sensor 2 -G188- at idling stop in display zone 2
Specification: 97 to 3%
- Depress accelerator slowly to full throttle position and observe angles displayed in display zones 1 and 2:
The percentage display in display zone 1 must increase evenly. The full tolerance range 3 to 93% is not always displayed.
The percentage display in display zone 2 must drop evenly. The full tolerance range 97 to 3% is not always displayed.
NOTE:
- The reason why the display in display zone 1 increases and the display in display zone 2 decreases is because the potentiometers (angle sensors) in the Throttle Valve Control Module -J338- run in opposite directions.
- This means that the voltage of one angle sensor moves towards 5 volts. (The more the throttle valve is opened the higher the voltage; the percentage figure increases).
- While the voltage of angle sensor 2 decreases from 5 volts towards 0 volts. (The more the throttle valve is opened the lower the voltage; the percentage figure decreases).
- Press the -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with the -Q- button.
- Switch off ignition.
If the display does not indicate as described:
- Pull 6-pin connector off Throttle Valve Control Module -J338- -arrow-.
Checking resistance
- Measure resistance from throttle valve drive between terminals 3 and 5
Specification: 1.0 to 5.0
If the specification is not obtained:
- Replace Throttle Valve Control Module -J338-, item 6.
- Check DTC memory, repair malfunctions if necessary and then erase DTC memory. Reading Diagnostic Trouble Codes
- Adapt Motronic Engine Control Module (ECM) -J220- to Throttle Valve Control Module -J338-.
- Read readiness code. If the DTC memory has been erased or the Motronic Engine Control Module (ECM) -J220- was disconnected from battery positive (B+), the 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 -J338- and wiring to control module.
- Check Throttle Position (TP) sensor:
If the voltage supply and wiring are OK.:
- Replace Motronic Engine Control Module (ECM) -J220-.
- Check DTC memory, repair malfunctions if necessary and then erase DTC memory. Reading Diagnostic Trouble Codes
- Erase learned values and adapt Motronic Engine Control Module (ECM) -J220- again.
- Read readiness code. If the DTC memory has been erased or the Motronic Engine Control Module (ECM) -J220- was disconnected from battery positive (B+), the readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes
Checking voltage supply and wiring to control module
- Connect multimeter to measure voltage at connector terminals 2 (positive) and 6 (ground (GND)).
- Switch on ignition.
Specification: at least 4.5 V
- Switch off ignition.
- Connect multimeter to measure voltage at connector terminal (positive) and ground (GND).
- Switch on ignition.
Specification: at least 4.5 V
- Switch off ignition.
If the specifications are not obtained:
- Remove wiper arms and cowl panel:
- Connect VAG 1598/31 test box to control module wiring harness. The Motronic Engine Control Module (ECM) -J220- remains disconnected.
- Check wiring for open circuit between test box socket and connector referring to Electrical Wiring Diagrams:
Terminal 1 and socket 92
Terminal 2 and socket 83
Terminal 3 and socket 117
Terminal 4 and socket 84
Terminal 5 and socket 118
Terminal 6 and socket 91
Wire resistance: max. 1.5 ohms
- Additionally check wiring for short to one another, to vehicle ground (GND) and to battery positive.
Specification: infinity ohms
If no wiring malfunction is detected:
- Check Motronic Engine Control Module (ECM) -J220- voltage supply .
Engine Control Module (ECM) Voltage Supply, Checking
- Check DTC memory, repair malfunctions if necessary and then erase DTC memory.
Reading Diagnostic Trouble Codes
- Read readiness code. If the DTC memory has been erased or the Motronic Engine Control Module (ECM) -J220- was disconnected from battery positive (B+), the readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes