With Manufacturer's Scan Tool

Angle Sensors For Throttle Drive, Checking

Special tools and equipment







- VAG1526A
- VAG1594A
- VAG1598/31
- VAS5051 with VAG5051/1

Angle sensor 1 for throttle drive (power accelerator activation) -G187- and angle sensor 1 for throttle drive (power accelerator activation) - G188- inform the Engine Control Module (ECM) about the position of throttle valve. Both angle sensors are located in throttle valve control module.

Test sequence
- Connect vehicle diagnostic, testing and information system VAS 5051 and select vehicle system "01 -Engine electronics" in selection. Ignition must be switched on. Connecting VAS 5051/VAG 1551 Scan Tool (ST)

Display on VAS 5051:







- Under -1- select diagnostic function "08 - Read measured value block".

Display on VAS 5051:







1 - Enter display group, max. entered value = 255
- Enter "062" for "display group number 062" in field -2- and confirm entry by pressing -Q- button.

Display on VAS 5051:







- Check specifications for electronic throttle potentiometer voltages in display fields -1- and -2-.

Display Group 062:

NOTE: Engine Control Module (ECM) calculates voltage values of angle sensors in percent relative to 5 volts and displays these percentage values. (5 volts supply voltage represents 100%).

- Observe display field 1 and 2.
- Slowly depress accelerator pedal completely.

Percent indication in display field 1 must rise uniformly. In the process, the tolerance range of 3 to 93% is not completely utilized.

Percent indication in display field 2 must decrease uniformly. The tolerance range 97 to 3% is not used completely during this.

NOTE:
- The reason why the value indicated in display field 1 climbs, while value indicated in display field 2 decreases, has to do with the fact that the potentiometers (angle sensors) in Throttle Valve Control Module -J338- run in opposite directions.
- This means the voltage of angle sensor 1 runs from 0 to 5 volts. (The more the throttle valve is opened, the larger the voltage; percent indication climbs).
- The voltage of angle sensor 2 runs from 5 to 0 volts. (The more the throttle valve is opened, the lower the voltage; the percentage decreases).

- Exit function "08 - Read measured value block" by pressing <- button.

If the displays are not as described:
- Check Throttle Valve Control Module -J338- voltage supply and wiring. Pay particular attention to connectors, which may be disconnected or corroded.
- Check Throttle Position (TP) sensor 2 -G185-. Testing and Inspection

Check voltage supply throttle valve control module
- Pull connector (2) off throttle valve control module.
- Switch ignition on.







- Connect multimeter for voltage measurement as follows:

Harness connector Specified value
Terminal
2 + Ground (GND) about 5 V
2 + 6 about 5 V

If specified values are not obtained:
- Check wire connections from Engine Control Module (ECM) to throttle valve control module.

Checking wire connections







- Pull connector (2) off throttle valve control module.
- Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Electrical Testing Using VAG1598/31 Test Box
- Check the following wire connections for open circuit and short circuit to Ground (GND) and B+:

Harness connector VAG1598/31 test box
Terminal Socket
1 92
2 83
3 117
4 84
5 118
6 91

- Repair open circuit or short circuit if necessary.

If no malfunctions are found in wires:
- Replace throttle valve control module.