Volkswagen New Beetle. Manual - part 1919

 

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Volkswagen New Beetle. Manual - part 1919

 

 

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

off. Following scan tool manufacturer's instructions, check brake system 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 Brake Servo Pressure sensor (G294) harness connector and wiring. Brake Servo Pressure sensor is 

located at front of brake master cylinder. See appropriate WIRING DIAGRAM under ENGINE 
PERFORMANCE in SYSTEM WIRING DIAGRAMS. Repair as necessary. After repairs, erase DTC 
memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE 
RELEARN PROCEDURE 
.  

DTC P2101/18533: THROTTLE VALVE CONTROL MODULE (J338) - MALFUNCTION 

Circuit/Component Description 

Throttle Valve Control Module (TVCM - J338) is located on throttle body. Throttle valve drive angle sensors 
and are located in TVCM (J338). ECM monitors throttle valve drive angle sensors for throttle valve position. 
ECM calculates throttle position based on percentage values sent by throttle valve drive angle sensors. Throttle 
valve drive angle sensors run in opposite directions of each other. Throttle Valve Drive Angle sensor No. 1 
(G187) displays throttle positions from 3-97 percent. Throttle Valve Drive Angle sensor No. 2 (G188) displays 
throttle positions from 97-3 percent. Throttle Valve Drive Angle sensor No. 1 (G187) ranges from 3-93 percent 
(0.15-4.65 volts), the larger the throttle opening the higher the percentage (voltage) reading. Throttle Valve 
Drive Angle sensor No. 2 (G188) ranges from 97-3 percent (4.90-0.15 volts), the larger the throttle opening the 
smaller the percentage (voltage) reading. When the engine is running (under load) the ECM can operate throttle 
valve independently of driver input.  

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 

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:

Test ranges for throttle valve drive angle sensors may not fully display on scan 

 

2003 Volkswagen New Beetle GLS 

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

  

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1. Turn ignition off. Disconnect TVCM (J338) 6-pin harness connector. Using DVOM check resistance 

between terminals No. 3 and 5 on TVCM. See Fig. 20 . Specification is one to 5 ohms. If resistance is 
okay, go to next step. If resistance is not okay, replace faulty TVCM. Erase DTC memory. Verify repair. 
Test is complete. Adapt TVCM (J338) to ECM (J220), see THROTTLE VALVE CONTROL 
MODULE (J338) 
. For vehicles with A/T, adapt TVCM (J338) to Transmission Control Module (J217), 
see A/T BASIC SETTING . On all models, perform ECM relearn procedure. See TEST DRIVE 
RELEARN PROCEDURE 
.  

2.  

Connect scan tool. See RETRIEVING DIAGNOSTIC TROUBLE CODES . Turn ignition on, engine 
off. Following scan tool manufacturer's instructions, observe percentage reading for Throttle Valve Drive 
Angle sensor No. 1 (G187) and Throttle Valve Drive Angle sensor No. 2 (G188).  

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

Throttle Valve Drive Angle sensor No. 1 (G187) and Throttle Valve Drive Angle sensor No. 2 (G188). 
Specification for Throttle Valve Drive Angle sensor No. 1 (G187) is 3 to 93 percent (0.15 to 4.65 volts). 
Specification for Throttle Valve Drive Angle sensor No. 2 (G188) is 97 to 3 percent (4.90 to 0.15 volts). 
If throttle valve drive angle sensor tests are not okay, go to step 6 . If throttle valve drive angle sensor 
tests are okay, go to next step.  

4. Check APP sensors. See DTC P0226/16610: ACCELERATOR PEDAL POSITION SENSOR 1 

(G79) ACCELERATOR PEDAL POSITION SENSOR 2 (G185), IMPLAUSIBLE SIGNAL . If 
APP sensors are not okay, go to next step. If APP sensors are okay. Erase DTC memory. Perform ECM 
relearn procedure. See TEST DRIVE RELEARN PROCEDURE . If code did not return on test drive, 
test is complete.  

5. Replace APP sensors. Erase DTC memory. Verify repair. Test is complete. For vehicles with A/T, adapt 

APP sensors to Transmission Control Module (J217). See A/T BASIC SETTING . On all models, 
perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

6. Turn ignition off. Disconnect ECM harness connector. Leave ECM disconnected from test box. Connect 

Test Box (VAG 1598/31) to ECM harness connector. See CONNECTING VAG TEST BOX . Using 
DVOM, check resistance between TVCM (J338) 6-pin harness connector and test box sockets, see 
TVCM (J338) 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 TVCM (J338) 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 

TVCM (J338) 6-PIN HARNESS CONNECTOR/VAG TEST BOX SOCKET IDENTIFICATION 

tool. No idle specifications for throttle valve drive angle sensors are given by 
manufacturer. 

NOTE:

If TVCM (J338) is replaced it must be adapted to the ECM and A/T control 
module (if equipped). 

TVCM 6-Pin Harness Connector Terminal 

VAG Test Box Socket 

92 

 

2003 Volkswagen New Beetle GLS 

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

  

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7. Turn ignition on. Using DVOM, measure voltage between TVCM (J338) 6-pin harness connector 

specified terminals. See TVCM (J338) VOLTAGE SPECIFICATIONS table. See Fig. 33 . Record 
voltage readings. If voltage readings are not okay, go to next step. If voltage readings are okay, resistance 
measurements are okay and no short circuits exist, replace faulty TVCM. After repairs, erase DTC 
memory. Verify repair. Test is complete. Adapt TVCM (J338) to ECM (J220). See THROTTLE 
VALVE CONTROL MODULE (J338) 
. For vehicles with A/T, adapt TVCM (J338) to Transmission 
Control Module (J217). See A/T BASIC SETTING . On all models, perform ECM relearn procedure. 
See TEST DRIVE RELEARN PROCEDURE 

TVCM (J338) VOLTAGE SPECIFICATIONS 

8. Check ECM voltage supply. See ECM GROUND & VOLTAGE SUPPLY under ECM (J220) - ME 

SFI CONTROL MODULE. If ECM ground circuits and ECM voltage supply are okay, go to next step. If 
ECM ground circuits and/or ECM voltage supply are not okay, repair as necessary. After repairs, erase 
DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE 
RELEARN PROCEDURE 
.  

9. Replace faulty ECM. See ENGINE CONTROL MODULE REMOVAL & INSTALLATION . Erase 

DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE 
RELEARN PROCEDURE 
.  

DTC P2122/18554, DTC P2127/18559, DTC P2128/18560 & DTC P2138/18570 

Code Definition 

z

DTC P2122/18554: Accelerator Pedal Position Sensor 1 (G79) - Signal Too Low  

z

DTC P2127/18559: Accelerator Pedal Position Sensor 2 (G185) - Signal Too Low  

z

DTC P2128/18560: Accelerator Pedal Position Sensor 2 (G185) - Signal Too High  

z

DTC P2138/18570: 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 
sensors sense the position of the accelerator pedal, not throttle position. 

83 

117 

84 

118 

91 

TVCM 6-Pin Harness Connector Terminals 

Voltage 

2 & Ground 

Minimum 4.5 

2 & 6 

Minimum 4.5 

 

2003 Volkswagen New Beetle GLS 

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

  

Helpmelearn Repair Manuals 

 

Wednesday, December 14, 2005 8:45:01 AM

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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). On all models except Passat, 
specification for APP sensor No. 1 (G79) is 6 to 96 percent (0.30 to 4.8 volts). For Passat models, 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 

2 & Ground 

Minimum 4.5 

2 & 3 

Minimum 4.5 

 

2003 Volkswagen New Beetle GLS 

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

  

Helpmelearn Repair Manuals 

 

Wednesday, December 14, 2005 8:45:01 AM

Page 301 

© 2004 Mitchell Repair Information Company, LLC. 

 

 

 

 

 

 

 

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