Volkswagen New Beetle. Manual - part 1915

 

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Volkswagen New Beetle. Manual - part 1915

 

 

Test Requirements 

Ensure battery is okay. 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.  

Test Procedure 

1. Check Climate Control Module (J255) for DTC(s). See appropriate AUTOMATIC A/C-HEATER 

SYSTEM article, under HVAC. If no DTCs are present, go to next step. If DTC(s) are present, repair as 
necessary. After repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn 
procedure. See TEST DRIVE RELEARN PROCEDURE .  

2. Check wiring between Climate Control Module (J255) and ECM (J220) for open or short circuits. See 

appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING 
DIAGRAMS. See Fig. 61 , Fig. 62 and Fig. 63 . If wiring is okay, go to next step. If wiring is not okay, 
repair as necessary. After repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM 
relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

3. Check centralized matching resistor in ECM. Turn ignition off. Connect ECM to test box, leave ECM 

harness connector disconnected from test box. Connect Test Box (VAG 1598/31). See CONNECTING 
VAG TEST BOX 
. Using DVOM, check resistance between test box sockets No. 58 and 60. Resistance 
should be 60-72 ohms. If resistance is not okay, replace faulty ECM. See ENGINE CONTROL 
MODULE REMOVAL & INSTALLATION 
. After repairs, erase DTC memory. Verify repair. Test is 
complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

DTC P1636/18044: DRIVETRAIN DATA BUS - NO SIGNAL FROM AIRBAG CONTROL MODULE 

SYSTEM WIRING DIAGRAMS article in ELECTRICAL and ECM GROUND & 
VOLTAGE SUPPLY . 

NOTE:

Engine control module communicates with all control modules capable of 
transferring data via a CAN (Controller Area Network) data bus. Data bus-
compatible control modules are connected together via two data bus wiring 
twisted together (CAN high and CAN low) and exchange information 
(messages). If information is not available in the CAN data bus from any one of 
the control modules in the CAN data bus system it will be recognized as a 
malfunction by the engine control module as well as other CAN data bus control 
modules. The CAN data bus requires a matching resistor to function fault-free. 
This central matching resistor is located in the engine control module. 

NOTE:

Automatic A/C-Heater SysteM is referred to by Volkswagen as the Climatronic 
system and is a fully automatic climate control system. 

NOTE:

Instrument Cluster Control Module (J285) and Can Data Bus OBD Interface 
(J533) are integral parts of the instrument cluster. If instrument cluster is 
replaced, Can Data Bus OBD Interface (J533) must be coded. See CAN DATA 
BUS OBD INTERFACE (J533) CODING . 

 

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2002-2003 ENGINE PERFORMANCE Self-Diagnostics - 1.8L Turbo

  

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(J234) 

Test Requirements 

Ensure battery is okay. 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.  

Test Procedure 

1. Check Air Bag Control Module (J234) for DTC(s). See DIAGNOSTICS in appropriate AIR BAG 

RESTRAINT SYSTEMS article, under RESTRAINTS. If DTC(s) are present, repair as necessary. After 
repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST 
DRIVE RELEARN PROCEDURE 
.  

2. Check wiring between Air Bag Control Module (J234) and ECM (J220) for open or short circuits. See 

appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING 
DIAGRAMS. See Fig. 61 , Fig. 62 and Fig. 63 . If wiring is okay, go to next step. If wiring is not okay, 
repair as necessary. After repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM 
relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

3. Check centralized matching resistor in ECM. Turn ignition off. Connect ECM to test box, leave ECM 

harness connector disconnected from test box. Connect Test Box (VAG 1598/31). See CONNECTING 
VAG TEST BOX 
. Using DVOM, check resistance between test box sockets No. 58 and 60. Resistance 
should be 60-72 ohms. If resistance is not okay, replace faulty ECM. See ENGINE CONTROL 
MODULE REMOVAL & INSTALLATION 
. After repairs, erase DTC memory. Verify repair. Test is 
complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

DTC P1639/18047: ACCELERATOR PEDAL POSITION SENSOR 1 (G79) ACCELERATOR PEDAL 
POSITION SENSOR 2 (G185) - IMPLAUSIBLE SIGNAL 

Circuit/Component Description 

APP sensor No. 1 (G79) and APP sensor No. 2 (G185) are located together as one unit in pedal assembly. APP 

NOTE:

If a test ends with ECM replacement. Before replacing ECM be certain that, all 
wiring, power and ground supplies are okay. See ENGINE PERFORMANCE in 
SYSTEM WIRING DIAGRAMS article in ELECTRICAL and ECM GROUND & 
VOLTAGE SUPPLY . 

NOTE:

Engine control module communicates with all control modules capable of 
transferring data via a CAN (Controller Area Network) data bus. Data bus-
compatible control modules are connected together via two data bus wiring 
twisted together (CAN high and CAN low) and exchange information 
(messages). If information is not available in the CAN data bus from any one of 
the control modules in the CAN data bus system it will be recognized as a 
malfunction by the engine control module as well as other CAN data bus control 
modules. The CAN data bus requires a matching resistor to function fault-free. 
This central matching resistor is located in the engine control module. 

 

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2002-2003 ENGINE PERFORMANCE Self-Diagnostics - 1.8L Turbo

  

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sensors sense the position of the accelerator pedal, not throttle position.  

When the engine is running (under load) the ECM can operate throttle valve independently of driver input.  

APP sensor No. 1 (G79) and APP sensor No. 2 (G185) communicate driver's intentions to ECM, fully 
independent of each other. APP sensor No. 1 (G79) and APP sensor No. 2 (G185). All models except Passat, 
specification for APP sensor No. 1 (G79) is 6 to 96 percent (0.30 to 4.8 volts). For Passat, Specification for APP 
sensor No. 1 (G79) is 12 to 97 percent (0.60 to 4.9 volts), the larger the throttle opening the higher the 
percentage (voltage) reading. For all models, APP Sensor No. 2 (G185) ranges from 3-48 percent (0.15 to 2.40 
volts), the larger the throttle opening the higher the percentage (voltage) reading.  

Test Requirements 

Ensure throttle valve is not damaged or dirty. 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 Procedure 

1. Connect scan tool, see RETRIEVING DIAGNOSTIC TROUBLE CODES . Turn ignition on, engine 

off. Following scan tool manufacturer's instructions, observe percentage reading on APP sensors No. 1 
(G79) and No. 2 (G185).  

2. Operate accelerator pedal slowly to Wide Open Throttle and observe percentage (voltage) readings for 

APP sensor No. 1 (G79) and APP sensor No. 2 (G185). All models except Passat, specification for APP 
sensor No. 1 (G79) is 6 to 96 percent (0.30 to 4.8 volts). For Passat, Specification for APP sensor No. 1 
(G79) is 12 to 97 percent (0.60 to 4.9 volts). All models, specification for APP sensor No. 2 (G185) is 3 
to 48 percent (0.15 to 2.40 volts). If percentage (voltage) is not okay, go to next step. If percentage 
(voltage) is okay, erase DTC memory. Test is complete. Perform ECM relearn procedure. See TEST 
DRIVE RELEARN PROCEDURE 
.  

3. Turn ignition off. Remove drive's side footwell cover and trim as necessary. Disconnect APP sensors 6-

pin harness connector. Turn ignition on. Check voltage supply at 6-pin harness connector. See Fig. 37 . 
See APP SENSOR VOLTAGE SPECIFICATIONS table. Turn ignition off. If no voltage is present, go 
to next step. If voltage tests are okay, erase DTC memory. Test is complete. Perform ECM relearn 
procedure. See TEST DRIVE RELEARN PROCEDURE 

APP SENSOR VOLTAGE SPECIFICATIONS 

NOTE:

Test ranges for accelerator position sensors may not fully display on scan tool. 
Percentage (voltage) should always be twice as large for APP sensor No. 1 
(G79) as the percentage (voltage) for APP sensor No. 2 (G185). No idle 
specifications for APP sensors are given by manufacturer. 

APP Sensor Harness Connector Terminals 

Voltage 

1 & Ground 

Minimum 4.5 

1 & 5 

Minimum 4.5 

 

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2002-2003 ENGINE PERFORMANCE Self-Diagnostics - 1.8L Turbo

  

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4.  

Turn ignition off. Disconnect ECM harness connector, leave ECM disconnected from test box. Connect 
Test Box (VAG 1598/31) or (VAG 1598/22) to ECM harness connector. See CONNECTING VAG 
TEST BOX 
. Using DVOM, check resistance between APP sensor circuits and test box sockets. See 
APP SENSOR 6-PIN HARNESS CONNECTOR/VAG TEST BOX SOCKET IDENTIFICATION 
table. Record resistance readings. Resistance should be a maximum of 1.5 ohms for each reading. Check 
wiring in APP sensor 6-pin harness connector for short circuits to one another, and for short circuits to B+ 
and ground. If resistance measurements are okay and no short circuits exist, go to next step. If any 
resistance measurement is not okay, or a short circuit exists, repair circuit(s), as necessary. After repairs, 
erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE 
RELEARN PROCEDURE 

APP SENSOR 6-PIN HARNESS CONNECTOR/VAG TEST BOX SOCKET IDENTIFICATION 

5. Replace faulty APP sensors No. 1 (G79) and No. 2 (G185). Accelerator position sensors are an integral 

part of the accelerator pedal assembly. After repairs, erase DTC memory. Adapt APP sensors to 
Transmission Control Module (J217). See A/T BASIC SETTING . Verify repair. Test is complete. 
Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

DTC P1640/18048: ECM (J220) - MALFUNCTION 

Test Requirements 

Ensure battery is okay. 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 coolant temperature is at least 176°
F (80°C).  

Test Procedure 

2 & Ground 

Minimum 4.5 

2 & 3 

Minimum 4.5 

NOTE:

If accelerator pedal assembly is replaced, APP sensors must be adapted 
to the A/T control module. 

NOTE:

APP sensor harness connector terminal No. 5 is for A/T models only. 

APP Sensor 6-Pin Harness Connector Terminal 

VAG Test Box Socket 

72 

73 

36 

35 

33 

34 

 

2003 Volkswagen New Beetle GLS 

2002-2003 ENGINE PERFORMANCE Self-Diagnostics - 1.8L Turbo

  

Helpmelearn Repair Manuals 

 

Wednesday, December 14, 2005 8:44:58 AM

Page 285 

© 2004 Mitchell Repair Information Company, LLC. 

 

 

 

 

 

 

 

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