Volkswagen New Beetle. Manual - part 1956

Fig. 4: Identifying VAG1598/31 Test Box 
Courtesy of VOLKSWAGEN OF AMERICA, INC. 

Requirement 

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Ignition switched off.  

Work procedure 

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Remove inner cover, left plenum chamber, to do this, slide center cover -1- of plenum chamber forward 
out of catch and remove from instrument panel.  

Fig. 5: Removing Inner Cover 
Courtesy of VOLKSWAGEN OF AMERICA, INC. 

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Remove three bolts -1-. 

 

2003 Volkswagen New Beetle GLS 

1998-2004 ENGINE PERFORMANCE On-Board Diagnostic (OBD), 1.8L Generic Scan Tool - New Beetle

  

Fig. 6: [Removing Three Bolts] 
Courtesy of VOLKSWAGEN OF AMERICA, INC. 

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Lift left cover -1- of plenum chamber in center of instrument panel (arrow A) and thereby unclip (front 
edge clips, rear edge clamps).  

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Pull cover -1- toward vehicle center out of bracket underneath Apillar (arrow B).  

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Then disengage connector from control module and disconnect.  

Fig. 7: Pulling Cover Toward Vehicle Center Out Of Bracket Underneath A Pillar 
Courtesy of VOLKSWAGEN OF AMERICA, INC. 

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Connect VAG1598/31 test box at control module wiring harness. Engine Control Module (ECM) is not 
connected. 

 

2003 Volkswagen New Beetle GLS 

1998-2004 ENGINE PERFORMANCE On-Board Diagnostic (OBD), 1.8L Generic Scan Tool - New Beetle

  

Fig. 8: Connecting VAG1598/31 Test Box At Control Module Wiring Harness 
Courtesy of VOLKSWAGEN OF AMERICA, INC. 

When harness connectors are disconnected from the Engine Control Module (ECM) or the battery is 
disconnected, all adaptation values in the control module are erased. DTC memory content will remain intact 
however. If the engine is started after this, rough, uneven idle can result. In this case, the readiness code must be 
generated again, see READINESS CODE, GENERATING . 

Check Malfunction Indicator Lamp (MIL) in instrument cluster 

Meaning of exhaust MIL 

The Malfunction Indicator Lamp (MIL) lights up when exhaust relevant malfunctions are recognized by the 
Engine Control Module (ECM). 

Component location of exhaust MIL 

Fig. 9: Identifying ECM Harness Connector Terminals

 

2003 Volkswagen New Beetle GLS 

1998-2004 ENGINE PERFORMANCE On-Board Diagnostic (OBD), 1.8L Generic Scan Tool - New Beetle

  

Courtesy of VOLKSWAGEN OF AMERICA, INC.

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Blinking: There is a malfunction that causes damage to the catalytic converter in this driving condition. In 
this case, vehicle must only be driven at reduced performance!  

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Continuously lit: There is a malfunction that causes increased emissions. Check DTC memory for 
Motronic control module.  

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DTC memory must still be checked if there are drivability problems or customer complaints and the MIL 
is not lit, since malfunctions can be stored without causing the MIL to light immediately.  

Recommended special tools and equipment 

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VAG1526 multimeter or VAG1715 multimeter  

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VAG1594 connector test kit  

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Wiring diagram  

Test requirement 

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The respective fuses of Malfunction Indicator Lamp (MIL) -K83- must be OK. Fuse holder is located 
behind access panel at far left end of dash. 

Fig. 10: Identifying Fuses 
Courtesy of VOLKSWAGEN OF AMERICA, INC. 

Test sequence 

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Switch on ignition: 

NOTE:

The Malfunction Indicator Lamp (MIL) can blink or remain lit continuously. DTC 
memory must be checked in each case, see DIAGNOSTIC MODE 3: CHECK DTC 
MEMORY .

 

2003 Volkswagen New Beetle GLS 

1998-2004 ENGINE PERFORMANCE On-Board Diagnostic (OBD), 1.8L Generic Scan Tool - New Beetle