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DTC P0120/16504 - TP Sensor Circuit Malfunction

NOTE: DTC is set with idle switch closed as soon as signal voltage of more than .72 volts is seen for longer than 2 seconds (corresponds to a throttle opening of more than 7 degrees).
  1. Inspect Throttle Position (TP) sensor connector for looseness and/or corrosion. Repair sensor connector as necessary. If sensor connector was not repaired, go to next step. If sensor connector was repaired, erase DTC memory. See CLEARING CODES  . Test drive vehicle. See TEST DRIVE.
  2. Turn ignition off. Ensure accelerator pedal cable is properly adjusted. See the ADJUSTMENTS article. Remove air intake sound absorber. Disconnect TP sensor connector. Using a DVOM, check continuity between TP sensor terminals No. 4 and 6.
  3. Continuity should be present. Open throttle slightly. DVOM should show infinity (no continuity). If continuity readings are not as specified, adjust TP sensor. See CLOSED THROTTLE POSITION (CTP) SWITCH in the ADJUSTMENTS article. After adjusting TP sensor, if continuity readings are as specified, go to step 5).
  4. If after adjusting TP sensor, continuity readings are not as specified, replace TP sensor. Erase DTC memory. See CLEARING CODES  . Test drive vehicle. See TEST DRIVE.
  5. Disconnect Powertrain Control Module (PCM) connectors. Connect VAG 1598/19 test box to PCM wiring harness. Terminal assignments of test box are identical to PCM connectors "A", "B", "C", "D" and "E".
  6. Using DVOM, check resistance between TP sensor terminal No. 4 (ground) and test box socket D12. Maximum resistance is one ohm. If resistance is within specification, go to next step. If resistance is not within specification, repair open circuit. Erase DTC memory. See procedures under CLEARING CODES  . Test drive vehicle. See TEST DRIVE.
  7. Using DVOM, check resistance between TP sensor terminal No. 6 (signal) and test box socket A4. Maximum resistance is one ohm. If resistance is within specification, circuit is okay. Erase DTC memory. See CLEARING CODES  . Test drive vehicle. See TEST DRIVE. If resistance is not within specification, repair open circuit. Erase DTC memory. See CLEARING CODES  . Test drive vehicle. See TEST DRIVE.
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