Volkswagen New Beetle. Manual - part 1843

 

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Volkswagen New Beetle. Manual - part 1843

 

 

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 

Accelerator Pedal Position (APP) sensor No. 1 (G79) and APP sensor No. 2 (G185) are located together as one 
unit in pedal assembly. APP 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. Specification for APP sensor No. 1 (G79) is 12-96 percent (0.60-4.9 volts). APP 
Sensor No. 2 (G185) ranges from 4-50 percent (0.20-2.50 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). On vehicles with M/T, gear shifter must be in neutral with parking brake set. On vehicles with A/T, selector 
lever must be in park or neutral with parking brake set.  

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). Specification for APP sensor No. 1 (G79) is 12-
97 percent (0.60-4.9 volts). Specification for APP sensor No. 2 (G185) is 4-50 percent (0.20-2.50 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. 26 . 
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 

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. 

 

2003 Volkswagen New Beetle GLS 

2001-2003 ENGINE PERFORMANCE Self-Diagnostics - 2.0L - Beetle, Golf & Jetta (Engine Codes AVH & AZG)

  

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procedure. See TEST DRIVE RELEARN PROCEDURE .  

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 
.  

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 P1648/18056: DRIVETRAIN DATA BUS MALFUNCTION 

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.  

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.  

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. 

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:

Instrument Cluster Control Module (J285) and Can Data Bus OBD Interface 
(J533) are integral parts of the instrument cluster. If instrument cluster is 

 

2003 Volkswagen New Beetle GLS 

2001-2003 ENGINE PERFORMANCE Self-Diagnostics - 2.0L - Beetle, Golf & Jetta (Engine Codes AVH & AZG)

  

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Test Procedure 

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

off. Following scan tool manufacturer's instructions, check Transmission Control Module (J217) and 
ABS Control Module (J104) for DTCs. 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 Transmission Control Module (J217), ABS Control Module (J104) and ECM 

(J220) for open or short circuits. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS 
article in ELECTRICAL. See Fig. 42 , Fig. 43 and Fig. 44 . 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.  

4. 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 P1650/18058: DRIVETRAIN DATA BUS - NO SIGNAL FROM INSTRUMENT CLUSTER 
CONTROL MODULE (J285) 

Engine control module communicates with all control modules capable of transferring bus 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.  

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.  

replaced, Can Data Bus OBD Interface (J533) must be coded. See CAN DATA 
BUS OBD INTERFACE (J533) CODING . 

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:

Instrument Cluster Control Module (J285) and Can Data Bus OBD Interface 

 

2003 Volkswagen New Beetle GLS 

2001-2003 ENGINE PERFORMANCE Self-Diagnostics - 2.0L - Beetle, Golf & Jetta (Engine Codes AVH & AZG)

  

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Test Procedure 

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

off. Following scan tool manufacturer's instructions, check Instrument Cluster Control Module (J285) for 
DTCs. 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 Instrument Cluster Control Module (J285) and ECM (J220) for open or short 

circuits. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. 
See Fig. 42 , Fig. 43 and Fig. 44 . 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 P1682/18090: DRIVETRAIN DATA BUS - IMPLAUSIBLE SIGNAL FROM ABS CONTROL 
MODULE (J104) 

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.  

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.  

(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 . 

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:

Instrument Cluster Control Module (J285) and Can Data Bus OBD Interface 
(J533) are integral parts of the instrument cluster. If instrument cluster is 

 

2003 Volkswagen New Beetle GLS 

2001-2003 ENGINE PERFORMANCE Self-Diagnostics - 2.0L - Beetle, Golf & Jetta (Engine Codes AVH & AZG)

  

Helpmelearn Repair Manuals 

 

Wednesday, December 14, 2005 8:50:01 AM

Page 175 

© 2004 Mitchell Repair Information Company, LLC. 

 

 

 

 

 

 

 

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