Throttle Position Sensor, Checking
THROTTLE POSITION SENSOR, CHECKING
Special tools, testers and auxiliary items
- VAG 1551 Scan Tool (ST) or vehicle system tester VAG 1552 with VAG 1551/3 adapter cable
- VAG 1598/18 test box
- Multimeter (Fluke 83 or equivalent)
- VW 1594 connector test kit
- Wiring diagram
Functional check
- Connect VAG 1551 scan tool (VAG 1552) and insert "Engine Electronics" address word 01. Carry out selection with ignition switched on. Refer to " On-Board Diagnostic". Testing and Inspection
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- to select "Read Measuring Value Block" function 08.
- Press -Q- button to confirm input.
Indicated on display
Read measuring value block HELP
Input display group number XXX
- Press -0-, -0- and -3- to input display group number 003.
- Press -Q- button to confirm input.
Indicated on display (1, 2, 3 and 4 = Display fields)
Read measuring value block 3 ->
1 2 3 4
NOTE: If something different is indicated on the display:
See Scan tool operating instructions.
- Check throttle valve angle at closed throttle position in display field 3.
Specification: 5-19 <°
- Slowly open throttle valve fully and observe angle displayed in display field 3.
- Value must increase uniformly over the complete range
- Check throttle valve angle at wide open throttle position in display field 3.
Specification: 85-101 <°
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06.
- Press -Q- button to confirm input.
- Switch ignition off.
NOTE: The displayed value is dependent on the tolerances of the throttle position sensor and does not correspond to the actual opening angle.
If the value does not increase uniformly:
- Replace throttle position sensor.
If the value remains constant:
- Continue check according to following table.
Checking voltage supply
- Separate 3-pin connector from throttle position sensor.
- Connect multimeter to measure voltage at connector terminals 1 and 3.
- Switch ignition on.
- Specification: min. 4.5 V
- Switch ignition off.
If the specification is not attained:
- Connect VAG 1598/18 test box to ECM wiring harness.
- Check wiring for open circuits between test box and 3-pin connector, according to wiring diagram.
- Terminal 1 and test box socket 41
- Terminal 3 and test box socket 33
- Wire resistance: Max. 1.5 Ohms
- Check wires at 3-pin connector for shorts to one another.
- Terminal 1 and test box socket 33
- Specification: Infinity Ohms (no continuity)
If no wiring malfunction is detected:
- Replace Motronic ECM J220
Checking wiring
- Connect VAG 1598/18 test box to ECM wiring harness.
If the display shows constant 0 <°:
- Check wire for short circuit to ground.
- test box sockets 1 and 40
- Specification: Infinity Ohms (no continuity)
If the display shows constant 106 <°:
- Switch ignition on.
- Check wire for short circuit to positive.
- Connect multimeter to measure voltage at test box sockets 1 and 40
- Specification: 0 volts
- Switch ignition off
Continuation if voltage is present:
If voltage of about 5 volts was present:
- Separate 3-pin connector to throttle position sensor.
- Switch ignition on.
- Check wiring at 3-pin connector terminals 1 and 2 for short circuit to one another according to wiring diagram.
Specification: Infinity Ohms
If the voltage was approx. battery positive voltage (B+):
- Check wire at 3-pin connector terminal 1 for short circuit to B+ according to wiring diagram.
Continuation if no voltage is present:
- Separate 3-pin connector to throttle position sensor.
- Check wiring for open circuits between test box and 3-pin connector, according to wiring diagram.
- Terminal 2 and test box socket 40
- Wire resistance: Max. 1.5 Ohms
If no wiring malfunction is detected:
- Replace throttle position sensor.