Volkswagen New Beetle. Manual - part 1842

 

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Volkswagen New Beetle. Manual - part 1842

 

 

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 

Check Air Bag Control Module (J234) for DTC(s). See appropriate AIR BAG RESTRAINTS SYSTEM 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 .  

DTC P1612/18020: ECM (J220) - INCORRECTLY CODED 

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). 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.  

ECM Coding 

Use scan tool to code ECM. See ENGINE CONTROL MODULE (J220) CODING .  

DTC P1626/18034: DRIVETRAIN DATA BUS, NO SIGNAL FROM TRANSMISSION CONTROL 
MODULE (J217) 

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.  

Test Procedure 

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 . 

 

2003 Volkswagen New Beetle GLS 

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

  

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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) 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) 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 
.  

4. 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 P1630/18038, P1631/18039, P1633/18041 & P1634/18042: ACCELERATOR PEDAL POSITION 
SENSOR SIGNAL 

Code Definition 

DTC P1630/18038 
Accelerator Pedal Position Sensor 1 (G79) - Signal Too Low 

DTC P1631/18039 
Accelerator Pedal Position Sensor 1 (G79) - Signal Too High 

DTC P1633/18041 
Accelerator Pedal Position Sensor 2 (G185) - Signal Too Low 

DTC P1634/18042 
Accelerator Pedal Position Sensor 2 (G185) - Signal Too High  

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. 

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 . 

 

2003 Volkswagen New Beetle GLS 

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

  

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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 12-97 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 
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 

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. 

NOTE:

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

 

2003 Volkswagen New Beetle GLS 

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

  

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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 P1636/18044: DRIVETRAIN DATA BUS - NO SIGNAL FROM AIRBAG CONTROL MODULE 
(J234) 

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.  

Test Procedure 

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

article under RESTRAINTS. 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 Air Bag Control Module (J234) 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 

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

 

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 171 

© 2004 Mitchell Repair Information Company, LLC. 

 

 

 

 

 

 

 

Content   ..  1840  1841  1842  1843   ..