Volkswagen New Beetle. Manual - part 1922

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

  

exhaust MIL must light up. 

If exhaust MIL does not light up when ignition is switched on: 

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Switch ignition off.  

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Check wire from ECM to exhaust MIL as follows:  

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Connect test box to control module wiring harness, see CONNECT TEST BOX FOR WIRING TEST . 

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Bridge sockets 2+47 of test box with the respective adapter cables.  

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Switch on ignition:  

exhaust MIL must light up. 

If Malfunction Indicator Lamp (MIL) does not light up: 

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Switch ignition off.  

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Remove instrument cluster: 

See INSTRUMENT CLUSTER, REMOVING AND INSTALLING 

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Check wire connection from Engine Control Module (ECM) to Malfunction Indicator Lamp (MIL) -K83-
according to wiring diagram.  

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Erase DTC memory of Engine Control Module (ECM), see DIAGNOSTIC MODE 4: RESET/ERASE 
DIAGNOSTIC DATA .  

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Generate readiness code, see READINESS CODE, GENERATING . 

If no malfunctions are detected in wire from Engine Control Module (ECM) to Malfunction Indicator 
Lamp (MIL): 

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Replace Motronic Engine Control Module (ECM) -J220-, see REPLACING ENGINE CONTROL 
MODULE (ECM) .  

If exhaust MIL lights up when ignition is switched on: 

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Start engine and let run at idle: 

Exhaust MIL must 

go out after a few seconds. 

If Malfunction Indicator Lamp (MIL) does not go out: 

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Switch ignition off.  

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Remove instrument cluster: 

 

2003 Volkswagen New Beetle GLS 

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

  

See INSTRUMENT CLUSTER, REMOVING AND INSTALLING

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Connect test box to control module wiring harness, see CONNECT TEST BOX FOR WIRING TEST . 

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Check wire connection between test box socket 47 and instrument cluster for short circuit to Ground 
(GND) according to wiring diagram.  

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Erase DTC memory of Engine Control Module (ECM), see DIAGNOSTIC MODE 4: RESET/ERASE 
DIAGNOSTIC DATA .  

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Generate readiness code, see READINESS CODE, GENERATING .  

If no malfunctions are detected in wire from Engine Control Module (ECM) to Malfunction Indicator Lamp 
(MIL): 

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Replace Motronic Engine Control Module (ECM) -J220-, see REPLACING ENGINE CONTROL 
MODULE (ECM) .  

SELECT DIAGNOSTIC MODE 

Recommended special tools and equipment: 

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VAS 5052 Vehicle Diagnostic and Information System with  

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VAS 5052/3 diagnostic cable  

Fig. 11: Identifying VAS 5052 Vehicle Diagnostic And Information System 
Courtesy of VOLKSWAGEN OF AMERICA, INC. 

Address word 33 - On-Board Diagnostic (OBD) 

Function 

Via the diagnostic tester, different diagnostic modes can be selected under "address word 33 - On-Board 
Diagnostic (OBD)". 

 

2003 Volkswagen New Beetle GLS 

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