DTC 00777 Questionable Signal
DTC Code 00777, Throttle Position Sensor G79:Questionable Signal
The Throttle Position sensor is located in the drivers footwell on the Accelerator Pedal. The TP sensor communicates the pedal position to the ECM.
Special Tools, Testers And Auxiliary Items:
- Fluke 83 Multimeter or equivalent
- VW 1594 Adaptor kit
Work Sequence
Display will appear as shown:
Rapid data transfer HELP
Select function XX
- Press 0 and 6 buttons to select Function 06 "End data transfer"
- Press Q button to enter input
- Switch OFF ignition
- Switch ignition back ON
- Press 0 and 1 buttons to select address word 01: "Engine electronics"
Display will appear as shown:
Rapid data transfer HELP
Select function XX
- Press 0 and 8 buttons to select Function 08 "Read measuring value block"
- Press Q button to enter input
Display will appear as shown:
Read measuring value block HELP
Input display group number XX
- Press 0 and 2 buttons to select "display group 02"
- Press Q button to enter input
Display will appear as shown:
Read measuring value block 2 -->
0 rpm 0.0% 0 1 0 18.4°C
- Observe Accelerator Pedal position in channel 2 (Do not press on Accelerator Pedal)
Specification: 0.0%
- Check Closed Throttle Position switch F60 in channel 3 (Center position must show 1)
Display: 0 1 0
Display will appear as shown:
Read measuring value block 2 -->
0 rpm 100% 0 0 0 18.4°C
- Slowly depress Accelerator Pedal until Wide Open Throttle is obtained, and observe values in channels 2 and 3
Channel 2: Pedal position value must increase continuously
Specification at Wide Open Throttle: 100%.
Channel 3: Center value must change to 0
Display: 0 0 0
NOTE: For vehicles with Automatic Transmission; the Kick Down Switch F8 pressure point must be distinctly felt before reaching Wide Open Throttle stop.
If final specification value not achieved:
- Press -> button
- Press 0 and 6 buttons to select Function 06 "End data transfor"
- Press Q button to enter input
- Switch OFF ignition
- Adjust Throttle Position (TP) sensor G79
If display does not change or is erratic:
- Check sensor as follows
- Press -> button
- Press buttons 0 and 6 to select Function 06 "End data transfer"
- Press Q button to enter input
- Switch OFF ignition
- Disconnect TP sensor -1-
- Measure sensor resistance between connector terminals 1 + 3
Pedal in Closed Throttle position
Specification: 1000 to 1500 ohm
Pedal in Wide Open Throttle position:
Specification: 1500 to 2500 ohm
- Check Closed Throttle Position switch F60 (in TP sensor) by measuring resistance between connector terminals 4 + 6
Pedal in Closed Throttle Position
Specification: max.1500.
Pedal depressed
Specification: infinite ohms
If specified resistance not obtained:
- Replace Throttle Position sensor G79
If specified resistance obtained:
- Connect VAG 1598/18 Test Box adaptor to ECM wiring harness
- Check wiring for open circuit between VAG 1598/18 Test Box adaptor and harness connector using wiring diagram:
Terminal 1 + socket 15
Terminal 2 + socket 57
Terminal 3 + socket 55
Terminal 4 + socket 65
Terminal 5 + socket 62
Terminal 6 + socket 33
Wire resistance: 1.5 ohm maximum
- Check for shorting between wires
Specification: infinite ohms
If no malfunction detected:
- Replace ECM J248