Volkswagen New Beetle. Manual - part 1811

 

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Volkswagen New Beetle. Manual - part 1811

 

 

DTC P0036/16420, P0037/16421 & P0038/16422: HO2S DOWNSTREAM TWC 

Code Definition 

DTC P0036/16420 
HO2 Sensor (G130) Downstream TWC - Heating Open Circuit 

DTC P0037/16421 
HO2 Sensor (G130) Downstream TWC - Heating Short To Ground 

DTC P0038/16422 
HO2 Sensor (G130) Downstream TWC - Heating Short To B+  

Test Requirements 

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 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. Check air induction and secondary air injection system for leaks. If no air leaks are found, go to next step. 

If air leaks are found. Repair as necessary. After repairs, erase DTC memory. Verify repair. Test is 
complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

2. Connect Scan Tool. See RETRIEVING DIAGNOSTIC TROUBLE CODES . Start engine and idle for 

two minutes. Following scan tool manufacturer's instructions, use scan tool to check downstream HO2S 
(G130) heater activation. Observe scan tool in downstream HO2S heater activation test mode. Heater 
actuation must switch, alternating from on to off. If HO2S heater remains in off mode, go to next step. If 
HO2S heater switches, alternating from on to off, go to next step (further testing is needed).  

3. Turn ignition off. Raise vehicle and remove HO2 sensors protective cover and disconnect downstream 

HO2S (G130) harness connector (Brown 4-pin). See Fig. 14 .  

4.  

mileage. After reconnecting ECM, it is necessary to perform relearn procedure. 
See TEST DRIVE RELEARN 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:

No resistance specification for HO2S heater circuit is 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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Wednesday, December 14, 2005 8:49:54 AM

Page 44 

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Using DVOM check heater circuit on HO2S for continuity. Connect DVOM between terminals No. 1 and 
2 of HO2S. See Fig. 15 . HO2S heater circuit should have continuity. If HO2S heater circuit has 
continuity, go to next step. If HO2S heater circuit is open, replace faulty downstream HO2S. After 
repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST 
DRIVE RELEARN PROCEDURE 
.  

5. Start engine and idle. Check voltage supply to HO2S heater. Connect DVOM between terminal No. 1 of 

HO2S harness connector and ground. See Fig. 16 . Voltage should be 11.0-14.5 volts. If voltage is okay, 
go to next step. If voltage is not okay. Turn ignition off. Using DVOM check resistance of HO2S harness 
connector terminal No. 1 to fuel pump relay (J17) harness connector. See ENGINE PERFORMANCE in 
SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Resistance should be a maximum of 1.5 
ohms. Repair as necessary. After repairs, erase DTC memory. Verify repair. Test is complete. Perform 
ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

6. Using DVOM and scan tool, check activation and voltage of heater circuit on HO2S. Connect DVOM 

between terminals No. 1 and 2 of HO2S harness connector. See Fig. 16 . Reconnect scan tool (if 
removed). Start engine and idle. Following scan tool manufacturer's instructions, use scan tool to check 
HO2S (G130) heater activation. Observe scan tool in downstream HO2S heater circuit activation mode. 
Observe voltage on DVOM. When scan tool shows heater circuit activation On, voltage should be 11.5-
14.5 volts. When scan tool shows heater circuit activation alternating from On to Off, voltage should 
alternate from 12-0 volts. Turn ignition off. If voltage and/or activation is not okay, go to next step. If 
voltage and activation are okay, erase DTC memory. Test is complete. Perform ECM relearn procedure. 
See TEST DRIVE RELEARN PROCEDURE .  

7.  

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 HO2S harness connector No. 2 and test box socket No. 63. See Fig. 16 . Resistance 
should be a maximum of 1.5 ohms. If resistance 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 
. If resistance is okay, and all wiring is okay, 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 
.  

NOTE:

Before replacing ECM check HO2S control signal. See DTC P0136/16520, 
DTC P0137/16521 & DTC P0138/16522 . If HO2S control signal is not within 
specifications it may set a DTC for HO2S heater malfunction. 

 

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 8:49:54 AM

Page 45 

© 2004 Mitchell Repair Information Company, LLC. 

Fig. 14: Locating Heated Oxygen Sensors Protective Cover & Identifying Harness Connectors (Beetle, 
Golf & Jetta)
 
Courtesy of VOLKSWAGEN UNITED STATES, INC.

 

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 8:49:54 AM

Page 46 

© 2004 Mitchell Repair Information Company, LLC. 

Fig. 15: Identifying Heated Oxygen Sensor Terminals - Downstream TWC 
Courtesy of VOLKSWAGEN UNITED STATES, INC.

 

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 8:49:54 AM

Page 47 

© 2004 Mitchell Repair Information Company, LLC. 

 

 

 

 

 

 

 

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