Volkswagen New Beetle. Manual - part 1869

 

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Volkswagen New Beetle. Manual - part 1869

 

 

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 . Using generic scan tool, 

following scan tool manufacturer's instructions, check aging of downstream HO2S.  

3.  

This test requires using Scan Tool VAG 1551/1552 or VAS 5051/5052. For A/T put vehicle gear selector 
lever in park. For M/T put vehicle gear shift lever in neutral. Apply parking brake. Start engine and idle. 
Using Scan Tool VAG 1551/1552 or VAS 5051/5052, go to "Display group 36". Allow engine to run at 
idle until scan tool display jumps from "Test off" to "Test on". Observe downstream HO2S voltage on 
scan tool display, voltage should increase. Allow engine to continue idling until scan tool displays 
specification "B1-S2 OK". If scan tool does not display "B1-S2 OK", go to next step. If scan tool displays 
"B1-S2 OK", erase DTC memory. Test is complete. Perform ECM relearn procedure. See TEST DRIVE 
RELEARN PROCEDURE 
.  

4. Test drive vehicle (to burn HO2S clean) and retest system. If test is okay after test drive, erase DTC 

memory. Test is complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN 
PROCEDURE 
. If test is not okay after test drive, ECM supplied basic voltage needs to be checked. Go 
to next step.  

5. Turn ignition off. For Passat, see Fig. 18 . For all other models. Raise vehicle and remove HO2 sensors 

protective cover and disconnect downstream HO2S (G130) harness connector (brown 4-pin), see Fig. 19 
Go to next step.  

6. Turn ignition off. Connect DVOM between terminals No. 3 and 4 of downstream HO2S harness 

connector, see Fig. 23 . Start engine, check ECM supplied basic voltage. Turn ignition off. Voltage 
should be 0.4 to 0.5 volt. If voltage is not okay, go to next step. If voltage is okay, replace downstream 
HO2S. After repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn 
procedure. See TEST DRIVE RELEARN PROCEDURE .  

7. 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 the following downstream HO2S harness connector terminals and test 
box sockets. See Fig. 23 . 

z

Downstream HO2S connector terminal No. 3 and test box socket No. 68.  

z

Downstream HO2S connector terminal No. 4 and test box socket No. 69.  

Resistance should be a maximum of 1.5 ohms for each reading. Check wiring in downstream HO2S 4-pin 
harness connector for short circuits to one another. If resistance measurements are okay and no short 
circuits exist. Replace downstream HO2S. After repairs, erase DTC memory. Verify repair. Test is 
complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE . 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 
.  

NOTE:

Catalytic converter must be 662° F (350° C) to 932° F (500° C) for scan tool 
to switch from "Test off" to "Test on". 

 

2003 Volkswagen New Beetle GLS 

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

  

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DTC P0141/16525: HO2 SENSOR (G130) DOWNSTREAM TWC - HEATING ELEMENT CIRCUIT 
MALFUNCTION 

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).  

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. For Passat, see Fig. 18 . For all other models. Raise vehicle and remove HO2 sensors 

protective cover and disconnect downstream HO2S (G130) harness connector (brown 4-pin), see Fig. 19 
Go to next step.  

4.  

Using DVOM check heater circuit on HO2S for continuity. Connect DVOM between terminals No. 1 and 
2 of HO2S. See Fig. 22 . 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. 23 . 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 appropriate WIRING 
DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. 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. 23 . Reconnect scan tool (if 

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 

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

  

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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 0-12 volts. Turn ignition off. If voltage and/or activation is not okay, go to next step. If 
voltage and activation are okay. 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. 23 . 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 
.  

DTC P0170/16554, DTC P0171/16555 & DTC P0172/16556 

Code Definition 

z

DTC P0170/16554: Fuel Trim - System Malfunction  

z

DTC P0171/16555: Fuel Trim - Too Lean  

z

DTC P0172/16556: Fuel Trim - Too Rich  

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 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, secondary air injection and exhaust system for leaks. Check air filter for blockage. If 

no air or exhaust leaks are found and air intake is unrestricted, go to next step. If air or exhaust leaks are 
found and/or air intake is restricted. Repair as necessary. After repairs, erase DTC memory. Verify repair. 
Test is complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

2.  

NOTE:

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

 

2003 Volkswagen New Beetle GLS 

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

  

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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 upstream HO2S G20 
control signal activation. HO2S control signal should be activated. Use scan tool to check upstream 
HO2S readiness. HO2S should be operationally ready. Observe scan tool in upstream HO2S heater 
activation test mode. Heater should be on. If HO2S heater is on, activation and readiness checks are okay. 
Go to next step (further testing is needed). If HO2S heater is off, or if HO2S activation or readiness 
checks are not okay, check HO2S heater. See DTC P0130/16514 & DTC P0135/16519 .  

3.  

Using scan tool, check upstream HO2S learned values at idle and part throttle. Learned values should be 
negative 10 to positive 10 percent (0.3 to 0.7 volt) at idle and part throttle. If learned values are okay, go 
to next step. If learned values are not okay and show a lean signal, go to step 6 . If learned values are not 
okay and show a rich signal, go to step 7 .  

4. Using scan tool, check upstream HO2S control signal switching. Values should be negative 10 to positive 

10 percent (0.3 to 0.7 volt) at idle and part throttle and must switch a minimum of 2 percent (0.1 volt). If 
test values are not as specified and faulty wiring is suspected, go to step 11 . If test values are not as 
specified and wiring is not suspect, go to next step. If test values are okay, erase DTC memory. Perform 
ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE . If no DTC resets test is 
complete.  

5. Test drive vehicle (to burn HO2S clean) and retest system. If test values are okay after test drive, go to 

next step. If test values are not okay after test drive, replace upstream HO2S. After repairs, erase DTC 
memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE 
RELEARN PROCEDURE 
.  

6. Check downstream HO2S control. See DTC P0136/16520, DTC P0137/16521 & DTC P0138/16522 . If 

downstream HO2S is okay, go to next step. If downstream HO2S is not okay, replace downstream HO2S. 
After repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See 
TEST DRIVE RELEARN PROCEDURE .  

7. Check for gasoline fouled engine oil. Change engine oil as necessary. Check fuel pressure and fuel 

pressure regulator. See FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. If 
fuel pressure is okay, go to next step. If fuel pressure 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 
.  

8. Check fuel injector volume (possible blocked or leaking injector). See FUEL SYSTEMS in appropriate 

SYSTEM & COMPONENT TESTING article. If fuel injector volume is okay, and fuel injectors do not 
leak more than 2 drops per minute each, go to next step. If fuel injector volume is not okay and /or any 
fuel injectors leak more than 2 drops per minute each, repair as necessary. After repairs, erase DTC 
memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE 

NOTE:

Upstream HO2S (G39) control signal activation may only occur above 1500 
RPM. 

NOTE:

Operating range of upstream HO2S is negative 25 to positive 25 percent 
when using Scan Tool VAG 1551/1552 or VAS 5051. Specified range of 
upstream HO2S is negative 10 to positive 10 percent when using Scan 
Tool VAG 1551/1552 or VAS 5051. In testing procedures negative 10 to 
positive 10 percent specification is allowed to vary slightly. 

 

2003 Volkswagen New Beetle GLS 

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

  

Helpmelearn Repair Manuals 

 

Wednesday, December 14, 2005 8:44:37 AM

Page 101 

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