Volkswagen New Beetle. Manual - part 1789

IAT Sensor (G72) - Short To Ground 

DTC P1161/17569 
IAT Sensor (G72) - Open Circuit/Short To B+  

Possible Effects 

Possible effect is engine pre-heating not functioning.  

Test Procedures 

1. Turn ignition off. Disconnect MAP/IAT sensor harness connector.  

2. Measure resistance between terminals No. 1 and 2 at MAP/IAT sensor (component side). Resistance 

should be 1500-2000 ohms at 86°F (30°C) and 275-375 ohms at 176°F (80°C). See Fig. 29 and Fig. 17 . 
If resistance is as specified, go to next step. If resistance is not as specified, replace MAP/IAT sensor. 
After repairs, erase DTC memory. See CLEARING DIAGNOSTIC TROUBLE CODES 
(FUNCTION 05) under SELF DIAGNOSTIC SYSTEM. Verify repair. Test is complete. Perform ECM 
relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

3. Turn ignition off. Disconnect ECM harness connector. Connect VAG 1598/31 test box to ECM harness 

connector. See CONNECTING VAG TEST BOX (leave ECM disconnected).  

4.  

Measure resistance between terminal No. 1 at MAP/IAT sensor harness connector and socket No. 52 at 
test box. See Fig. 14 and Fig. 15 . Measure resistance between terminal No. 2 at MAP/IAT sensor harness 
connector and socket No. 73 at test box. Both resistances should be less than 1.5 ohms. If resistances are 
as specified, go to next step. If any resistance is not as specified, repair open in wiring between MAP/IAT 
sensor and ECM. After repairs, erase DTC memory. See CLEARING DIAGNOSTIC TROUBLE 
CODES (FUNCTION 05) under SELF DIAGNOSTIC SYSTEM. Verify repair. Test is complete. 
Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

5. Measure resistance between terminals No. 1 and 2 at MAP/IAT sensor harness connector. Resistance 

should be infinite. If resistance is as specified, go to next step. If resistance is not as specified, repair 
circuits shorted to each other between MAP/IAT sensor and ECM. After repairs, erase DTC memory. See 

NOTE:

IAT sensor in an integral part of Manifold Absolute Pressure (MAP) sensor. 

NOTE:

For connector terminal wire colors, see appropriate WIRING DIAGRAM under 
ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. For component 
locations, see Fig. 14 . 

NOTE:

Before replacing any component, ensure all connectors at component and ECM 
are clean and tight. After making any repairs, disconnect ECM harness 
connector for 10 seconds, connect ECM harness connector and retest system. 
It is necessary to generate an ECM readiness code if ECM memory is cleared, 
battery voltage is disconnected or ECM is disconnected. 

NOTE:

Test box socket numbers correspond to ECM pin numbers. 

 

2003 Volkswagen New Beetle GLS 

2002-2004 ENGINE PERFORMANCE Self-Diagnostics - 1.9L Turbo Diesel - Beetle, Golf & Jetta (Engine Code ALH)

  

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CLEARING DIAGNOSTIC TROUBLE CODES (FUNCTION 05) under SELF DIAGNOSTIC 
SYSTEM. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE 
RELEARN PROCEDURE .  

6. Measure resistance between ground and terminals No. 1 and 2 at MAP/IAT sensor harness connector. 

Both resistances should be infinite. If resistances are as specified, go to next step. If any resistance is not 
as specified, repair short to ground in wiring between MAP/IAT sensor and ECM. After repairs, erase 
DTC memory. See CLEARING DIAGNOSTIC TROUBLE CODES (FUNCTION 05) under SELF 
DIAGNOSTIC SYSTEM. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST 
DRIVE RELEARN PROCEDURE .  

7. Measure resistance between positive battery terminal and terminals No. 1 and 2 at MAP/IAT sensor 

harness connector. Both resistances should be infinite. If resistances are as specified, replace ECM. If any 
resistance is not as specified, repair short to voltage in wiring between MAP/IAT sensor and ECM. After 
repairs, erase DTC memory. See CLEARING DIAGNOSTIC TROUBLE CODES (FUNCTION 05) 
under SELF DIAGNOSTIC SYSTEM. Verify repair. Test is complete. Perform ECM relearn procedure. 
See TEST DRIVE RELEARN PROCEDURE .  

Fig. 29: Identifying MAP/IAT Sensor Terminals 
Courtesy of VOLKSWAGEN UNITED STATES, INC. 

DTC P1245/17653, DTC P1246/17654 & DTC P1247/17655 

Code Definition 

DTC P1245/17653 
Needle Lift Sensor (G80) - Short To Ground 

DTC P1246/17654 
Needle Lift Sensor (G80) - Implausible Signal 

 

2003 Volkswagen New Beetle GLS 

2002-2004 ENGINE PERFORMANCE Self-Diagnostics - 1.9L Turbo Diesel - Beetle, Golf & Jetta (Engine Code ALH)

  

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DTC P1247/17655 
Needle Lift Sensor (G80) - Open Circuit/Short To B+  

Possible Effects 

Possible effects are glow plug indictor light blinks, engine runs rough, lack of power and/or increased 
emissions.  

Test Procedures 

1. Turn ignition off. Disconnect needle lift sensor harness connector. Needle Lift Sensor (G80) is located on 

No. 3 injector.  

2. Measure resistance between terminals No. 1 and 2 at needle lift sensor (component side). Resistance 

should be 80-120 ohms. If resistance is as specified, go to next step. If resistance is not as specified, 
replace needle lift sensor with No. 3 injector. After repairs, erase DTC memory. See CLEARING 
DIAGNOSTIC TROUBLE CODES (FUNCTION 05) under SELF DIAGNOSTIC SYSTEM. Verify 
repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN 
PROCEDURE .  

3. Turn ignition off. Disconnect ECM harness connector. Connect VAG 1598/31 test box to ECM harness 

connector, see CONNECTING VAG TEST BOX (leave ECM disconnected).  

4.  

Measure resistance between terminal No. 1 at needle lift sensor harness connector and socket No. 109 at 
test box. See Fig. 30 . Measure resistance between terminal No. 2 at needle lift sensor harness connector 
and socket No. 101 at test box. Both resistances should be less than 1.5 ohms. If resistances are as 
specified, go to next step. If any resistance is not as specified, repair open in wiring between needle lift 
sensor and ECM. After repairs, erase DTC memory. See CLEARING DIAGNOSTIC TROUBLE 
CODES (FUNCTION 05) under SELF DIAGNOSTIC SYSTEM. Verify repair. Test is complete. 
Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

5. Measure resistance between terminals No. 1 and 2 at needle lift sensor harness connector. See Fig. 30 . 

Resistance should be infinite. If resistance is as specified, go to next step. If resistance is not as specified, 
repair circuits shorted to each other between needle lift sensor and ECM. After repairs, erase DTC 
memory. See CLEARING DIAGNOSTIC TROUBLE CODES (FUNCTION 05) under SELF 
DIAGNOSTIC SYSTEM. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST 

NOTE:

For connector terminal wire colors, see appropriate WIRING DIAGRAM under 
ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. For component 
locations, see COMPONENT LOCATIONS . 

NOTE:

Before replacing any component, ensure all connectors at component and ECM 
are clean and tight. After making any repairs, disconnect ECM harness 
connector for 10 seconds, connect ECM harness connector and retest system. 
It is necessary to generate an ECM readiness code if ECM memory is cleared, 
battery voltage is disconnected or ECM is disconnected. 

NOTE:

Test box socket numbers correspond to ECM pin numbers. 

 

2003 Volkswagen New Beetle GLS 

2002-2004 ENGINE PERFORMANCE Self-Diagnostics - 1.9L Turbo Diesel - Beetle, Golf & Jetta (Engine Code ALH)

  

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DRIVE RELEARN PROCEDURE .  

6. Measure resistance between ground and terminals No. 1 and 2 at needle lift sensor harness connector. 

Both resistances should be infinite. If resistances are as specified, go to next step. If any resistance is not 
as specified, repair short to ground in wiring between needle lift sensor and ECM. After repairs, erase 
DTC memory. See CLEARING DIAGNOSTIC TROUBLE CODES (FUNCTION 05) under SELF 
DIAGNOSTIC SYSTEM. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST 
DRIVE RELEARN PROCEDURE .  

7. Measure resistance between positive battery terminal and terminals No. 1 and 2 at needle lift sensor 

harness connector. Both resistances should be infinite.  

8. If any resistance is not as specified, repair short to voltage in wiring between needle lift sensor and ECM. 

After repairs, erase DTC memory. See CLEARING DIAGNOSTIC TROUBLE CODES 
(FUNCTION 05) under SELF DIAGNOSTIC SYSTEM. Verify repair. Test is complete. Perform ECM 
relearn procedure. See TEST DRIVE RELEARN PROCEDURE . If resistances are as specified, 
replace faulty ECM. After repairs, erase DTC memory. See CLEARING DIAGNOSTIC TROUBLE 
CODES (FUNCTION 05) under SELF DIAGNOSTIC SYSTEM. Verify repair. Test is complete. 
Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

 

2003 Volkswagen New Beetle GLS 

2002-2004 ENGINE PERFORMANCE Self-Diagnostics - 1.9L Turbo Diesel - Beetle, Golf & Jetta (Engine Code ALH)

  

Helpmelearn Repair Manuals 

 

Wednesday, December 14, 2005 8:48:23 AM

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