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Engine Controls - Self-Diagnostics - 1.8L Turbo: Other Audi A4 B5 facelift

Testing & Diagnostics ~1540 words

Knock Sensor No. 1

  1. Inspect knock sensor 3-pin connector for looseness and/or corrosion. Knock sensor No. 1 is located at left side of engine, under intake manifold near front of engine. Repair sensor connector as necessary. If sensor connector was not repaired, go to next step. If connector was repaired, erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  2. Turn ignition off. Disconnect engine speed sensor 3-pin connector. Using DVOM, check resistance between specified knock sensor 3-pin connector (sensor side) terminals. Knock sensor terminals No. 1 and 2. Knock sensor terminals No. 1 and 3. Knock sensor terminals No. 2 and 3. Resistance should be infinity. If resistance is infinity, go to next step. If resistance is not infinity, replace knock sensor. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  3. Disconnect Powertrain Control Module (PCM) connectors. Connect VAG 1598/22 test box to PCM wiring harness. Using DVOM, check resistance between knock sensor connector (harness side) terminals and specified test box sockets. Knock sensor connector terminal No. 1 and test box socket 68. Knock sensor connector terminal No. 2 and test box socket 67. Knock sensor connector terminal No. 3 and test box socket 2. Resistance should be 1.5 ohms or less. If resistance is within specification, go to next step. If resistance is not within specification, repair wiring harness open as necessary. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  4. Using DVOM, check resistance between knock sensor connector (harness side) terminals and specified test box sockets. Knock sensor connector terminal No. 2 and test box socket 68. Knock sensor connector terminal No. 3 and test box socket 68. Knock sensor connector terminal No. 3 and test box socket 67. Resistance should be infinity. If resistance is infinity, go to next step. If resistance is not infinity, repair wiring harness short as necessary. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  5. Loosen knock sensor No. 1 and re-tighten to 15 ft. lbs. (20 N.m). Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article. If DTC is still in memory, replace faulty knock sensor No. 1. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.

Knock Sensor No. 2

  1. Inspect knock sensor 3-pin connector for looseness and/or corrosion. Knock sensor No. 2 is located at left side of engine, under intake manifold near rear of engine. Repair sensor connector as necessary. If sensor connector was not repaired, go to next step. If connector was repaired, erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  2. Turn ignition off. Disconnect engine speed sensor 3-pin connector. Using DVOM, check resistance between specified knock sensor 3-pin connector (sensor side) terminals. Knock sensor terminals No. 1 and 2. Knock sensor terminals No. 1 and 3. Knock sensor terminals No. 2 and 3. Resistance should be infinity. If resistance is infinity, go to next step. If resistance is not infinity, replace knock sensor. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  3. Disconnect Powertrain Control Module (PCM) connectors. Connect VAG 1598/22 test box to PCM wiring harness. Using DVOM, check resistance between knock sensor connector (harness side) terminals and specified test box sockets. Knock sensor connector terminal No. 1 and test box socket 60. Knock sensor connector terminal No. 2 and test box socket 67. Knock sensor connector terminal No. 3 and test box socket 2. Resistance should be 1.5 ohms or less. If resistance is within specification, go to next step. If resistance is not within specification, repair wiring harness open as necessary. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  4. Using DVOM, check resistance between knock sensor connector (harness side) terminals and specified test box sockets. Knock sensor connector terminal No. 2 and test box socket 60. Knock sensor connector terminal No. 3 and test box socket 60. Knock sensor connector terminal No. 3 and test box socket 67. Resistance should be infinity. If resistance is infinity, go to next step. If resistance is not infinity, repair wiring harness short as necessary. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  5. Loosen knock sensor No. 2 and re-tighten to 15 ft. lbs. (20 N.m). Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article. If DTC is still in memory, replace faulty knock sensor No. 2. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  1. Inspect knock sensor No. 1 connector for looseness and/or corrosion. Knock sensor No. 1 is located on driver side of engine under intake manifold closer to front of engine. Repair sensor connector as necessary. If sensor connector was not repaired, go to next step. If sensor connector was repaired, erase DTC memory and test drive vehicle. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  2. Using a DVOM, measure resistance between the following knock sensor connector (sensor side) terminals: Knock sensor terminals No. 1 and 3. Knock sensor terminals No. 1 and 3. Knock sensor terminals No. 2 and 3. Resistance specification is infinity (no continuity). If resistance is infinity, go to next step. If resistance is not infinity, replace knock sensor No. 1. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  3. Turn ignition off. Connect VAG 1598/22 test box to PCM harness connector. Using a DVOM, measure resistance between knock sensor connector (harness side) and the following terminals: Knock sensor connector (harness side) terminal No. 1 and test box socket 68. Knock sensor connector (harness side) terminal No. 2 and test box socket 67. Knock sensor connector (harness side) terminal No. 3 and test box socket 2. Resistance specification is 1.5 ohms or less. If resistance is within specification, go to next step. If resistance is not within specification, repair open in wiring harness as necessary. See appropriate wiring diagram in «WIRING DIAGAMS»(ref-3061) article. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  4. Using a DVOM, measure resistance between knock sensor connector (harness side) and the following terminals: Knock sensor connector (harness side) terminal No. 2 and test box socket 68. Knock sensor connector (harness side) terminal No. 3 and test box socket 68. Knock sensor connector (harness side) terminal No. 3 and test box socket 67. Resistance specification is infinity. If resistance is infinity, go to next step. If resistance is not infinity, repair short in wiring harness as necessary. See appropriate wiring diagram in «WIRING DIAGAMS»(ref-3061) article. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  5. Loosen knock sensor No. 1 mounting bolt and retighten to 15 ft. lbs. (20 N.m). If DTC still exists, replace knock sensor No. 1. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article. If DTC no longer is stored, erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  1. Inspect knock sensor No. 2 connector for looseness and/or corrosion. Knock sensor No. 2 is located on driver side of engine under intake manifold closer to rear of engine. Repair sensor connector as necessary. If sensor connector was not repaired, go to next step. If sensor connector was repaired, erase DTC memory and test drive vehicle. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  2. Using a DVOM, measure resistance between the following knock sensor connector (sensor side) terminals: Knock sensor terminals No. 1 and 2. Knock sensor terminals No. 1 and 3. Knock sensor terminals No. 2 and 3. Resistance specification is infinity (no continuity). If resistance is infinity, go to next step. If resistance is not infinity, replace knock sensor No. 2. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  3. Turn ignition off. Connect VAG 1598/22 test box to PCM harness connector. Using a DVOM, measure resistance between knock sensor connector (harness side) and the following terminals: Knock sensor connector (harness side) terminal No. 1 and test box socket 60. Knock sensor connector (harness side) terminal No. 2 and test box socket 67. Knock sensor connector (harness side) terminal No. 3 and test box socket 2. Resistance specification is 1.5 ohms or less. If resistance is within specification, go to next step. If resistance is not within specification, repair open in wiring harness as necessary. See appropriate wiring diagram in «WIRING DIAGAMS»(ref-3061) WIRING DIAGRAMS article. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  4. Using a DVOM, measure resistance between knock sensor connector (harness side) and the following terminals: Knock sensor connector (harness side) terminal No. 2 and test box socket 60. Knock sensor connector (harness side) terminal No. 3 and test box socket 60. Knock sensor connector (harness side) terminal No. 3 and test box socket 67. Resistance specification is infinity. If resistance is infinity, go to next step. If resistance is not infinity, repair short in wiring harness as necessary. See apprpriate wiring diagram in «WIRING DIAGAMS»(ref-3061) article. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.
  5. Loosen knock sensor No. 2 mounting bolt and retighten to 15 ft. lbs. (20 N.m). If DTC still exists, replace knock sensor No. 2. Erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article. If DTC no longer is stored, erase DTC memory. See CLEARING CODES in «SELF-DIAGNOSTICS - INTRODUCTION»(ref-3050) article.

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