Volkswagen New Beetle. Manual - part 1784

 

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Volkswagen New Beetle. Manual - part 1784

 

 

Boost Pressure Regulation - Control Limit Exceeded  

Possible Effects 

Possible effect is boost pressure too high or reduce power.  

Test Requirements 

Ensure all fuses are okay, battery voltage is at least 11.5 volts and fuel pump relay is okay. Ensure all electrical 
accessories are off and A/C is off. Ensure engine is mechanically sound. Ensure no intake or exhaust system 
leaks exist. Ensure engine coolant temperature is at least 176°F (80°C).  

Test Procedures 

1. Verify battery voltage is a minimum of 11.5 volts and all fuses are okay. Repair as necessary. Connect 

Scan Tool VAG 1551/1552 or 5051/5052. See Fig. 1 .  

2. Start engine and idle. Using scan tool access "Display group 11". With a helper to operate scan tool from 

rear seat, accelerate vehicle in 3rd gear from about 1500 RPM to wide open throttle. Press VAG 1551 
PRINT button at approximately 3000 RPM. Boost value should be 24.5-32 psi (1.7-2.2 bar). If specified 
boost pressure is not attained, go to next step.  

3. Check Wastegate by-pass regulator valve, see DTC P0245/1629, P0246/16630, P1546/17954 & 

P1549/17957 . Repeat turbocharger test. If Wastegate by-pass regulator valve was replaced and boost 
pressure is still to low, go to next step. If Wastegate by-pass regulator valve was replaced and boost 
pressure is okay, 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 

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:

When using scan tool to activate wastegate by-pass regulator valve, it is barely 
audible. Check by touch or use mechanics stethoscope if necessary. 

NOTE:

Manufacturer recommends using Scan Tool (VAG 1551/VAG 1552, VAS 
5051/VAS 5052) and Test Box (VAG 1598) to diagnose this code. Follow test 
equipment manufacturer's instructions for operation. If scan tool is not 
available, check components and wiring for damage. See appropriate WIRING 
DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. 

 

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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Wednesday, December 14, 2005 8:48:21 AM

Page 48 

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4. Inspect turbo charger and waste gate, repair or replace as necessary. 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 
.  

DTC P0245/16629, DTC P0246/16630, DTC P1546/17954 & DTC P1549/17957 

Code Definition 

DTC P0245/16629 
Wastegate By-Pass Regulator Valve (N75) - Open Circuit/Short To Ground 

DTC P0246/16630 
Wastegate By-Pass Regulator Valve (N75) - Short To Positive 

DTC P1546/17954 
Wastegate By-Pass Regulator Valve (N75) - Short To Positive 

DTC P1549/17957 
Wastegate By-Pass Regulator Valve (N75) - Open Circuit/Short To Ground  

Possible Effects 

Possible effects are boost pressure too low and/or lack of power.  

Test Procedures 

1. Turn ignition off. Locate wastegate by-pass regulator valve. See COMPONENT LOCATIONS and Fig. 

22 .  

2. Disconnect harness connector from wastegate by-pass regulator valve. Measure resistance between 

wastegate by-pass regulator valve terminals. See Fig. 22 . If resistance is between 14-20 ohms, go to next 
step. If resistance is not 14-20 ohms, replace wastegate by-pass regulator valve. After repairs, erase DTC 

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:

When using scan tool to activate wastegate by-pass regulator valve, it is barely 
audible. Check by touch or use mechanics stethoscope if necessary. 

 

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 8:48:21 AM

Page 49 

© 2004 Mitchell Repair Information Company, LLC. 

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. Verify battery voltage is a minimum of 11.5 volts and all fuses are okay. Repair as necessary. Connect 

Scan Tool VAG 1551/1552 or 5051/5052. See Fig. 1 . Turn ignition on, engine off.  

4. Using scan tool, activate wastegate by-pass regulator valve. Wastegate by-pass regulator valve should 

audibly click. If wastegate by-pass regulator valve does not click, go to next step. If wastegate by-pass 
regulator valve clicks check vacuum supply to wastegate by-pass regulator valve. Repair as necessary. 
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. Disconnect wastegate by-pass regulator valve 2-pin connector. See Fig. 22 . Turn ignition on, with engine 

off.  

6. Using DVOM and adapter cables from Test Kit (VAG 1594), measure voltage between wastegate by-pass 

regulator valve 2-pin harness connector terminal 1 and engine ground. Battery voltage should be present. 
Turn ignition off. If readings are not okay, go to next step. If readings are okay, replace faulty wastegate 
by-pass regulator valve. 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. Turn ignition off. Disconnect ECM harness connector. Connect Test Box (VAG 1598/22) to ECM 

harness connector. See CONNECTING VAG TEST BOX .  

8.  

Using DVOM, check resistance between the following wastegate by-pass regulator valve (N75) 2-pin 
harness connector terminals and test box sockets. See Fig. 30 . 

z

Wastegate By-Pass Regulator Valve (N75) harness connector terminal No. 1 and test box socket 
No. 1.  

z

Wastegate By-Pass Regulator Valve (N75) harness connector terminal No. 1 and test box socket 
No. 2.  

z

Wastegate By-Pass Regulator Valve (N75) harness connector terminal No. 2 and test box socket 
No. 62.  

9. Resistance should be a maximum of 1.5 ohms for each reading. If resistance is not okay, repair as 

necessary. Verify repair. Test is complete. Check wires in wastegate by-pass regulator valve 2-pin 
harness connector for short circuits to one another, also for short circuits to battery positive and ground. If 
wiring is not okay, repair as necessary. Verify repair. Test is complete.  

10. If resistance is okay and all wiring is okay, replace faulty ECM. See ENGINE CONTROL MODULE 

under REMOVAL, OVERHAUL & INSTALLATION. 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 
.  

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)

  

Helpmelearn Repair Manuals 

 

Wednesday, December 14, 2005 8:48:22 AM

Page 50 

© 2004 Mitchell Repair Information Company, LLC. 

Fig. 22: Identifying Test Points On Wastegate By-Pass Valve (N75) (Golf & Jetta - 1.9L Turbo Diesel) 
Courtesy of VOLKSWAGEN UNITED STATES, INC. 

DTC P0300/16684, DTC P0301/16685, DTC P0302/16686, DTC P0303/16687 & DTC P0304/16688 

Code Definition 

DTC P0300/16684 
Misfire Recognized 

DTC P0301/16685 
Misfire Recognized - Cylinder No. 1 

DTC P0302/16686 
Misfire Recognized - Cylinder No. 2 

DTC P0303/16687 

 

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 8:48:22 AM

Page 51 

© 2004 Mitchell Repair Information Company, LLC. 

 

 

 

 

 

 

 

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