Volkswagen New Beetle. Manual - part 1817

 

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Volkswagen New Beetle. Manual - part 1817

 

 

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. 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 
.  

DTC P0170/16554, P0171/16555 & P0172/16556: FUEL TRIM 

Code Definition 

DTC P0170/16554 
Fuel Trim - System Malfunction 

DTC P0171/16555 
Fuel Trim - Too Lean 

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 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. Check air filter for blockage. If no air 

NOTE:

Before replacing ECM check HO2S control signal. See DTC P0136/16522, 
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)

  

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leaks are found and air intake is unrestricted, 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 upstream HO2S 
(G39) 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 activation and readiness checks are okay and HO2S heater is 
on. 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, 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 .  

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 .  

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

pressure regulator. See FUEL SYSTEMS in 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, go to next step. If fuel 
injector volume 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 .  

9. Check to see if EVAP canister purge valve (N80) is stuck in the open position. See DTC P0440/16824 & 

DTC P0441/16825 . If EVAP canister purge valve is okay go to next step. If EVAP canister purge valve 

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 

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

  

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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 .  

10.  

Check MAF sensor (G70). See DTC P0101/16485, DTC P0102/16486 & DTC P0103/16487 . If MAF 
sensor is okay, go to next step. If MAF sensor 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 
.  

11. Turn ignition off. Raise vehicle and remove HO2 sensors protective cover. Disconnect upstream HO2S 

(G39) harness connector (Black 6-pin). See Fig. 14 .  

12. 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 upstream HO2S connector terminals and test box 
sockets. See Fig. 22 . 

z

Upstream HO2S connector terminal No. 1 and test box socket No. 70.  

z

Upstream HO2S connector terminal No. 2 and test box socket No. 71.  

z

Upstream HO2S connector terminal No. 5 and test box socket No. 51.  

z

Upstream HO2S connector terminal No. 6 and test box socket No. 52.  

Resistance should be a maximum of 1.5 ohms for each reading. Check wiring in upstream HO2S 6-pin 
harness connector for short circuits to one another. If resistance measurements are okay and no short 
circuits exist. Replace upstream 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 
.  

DTC P0201/16585, P0202/16586, P0203/16587 & P0204/16588: FUEL INJECTOR CIRCUIT 
MALFUNCTION 

Code Definition 

DTC P0201/16585 
Injector Cylinder 1 (N30) - Electrical Circuit Malfunction 

DTC P0202/16586 
Injector Cylinder 2 (N31) - Electrical Circuit Malfunction 

DTC P0203/16587 
Injector Cylinder 3 (N32) - Electrical Circuit Malfunction 

DTC P0204/16588 
Injector Cylinder 4 (N33) - Electrical Circuit Malfunction 

NOTE:

If MAF sensor (G70) malfunctions, a DTC for MAF sensor should be 
present in ECM memory. 

 

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 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 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 . Using scan tool, check 
activation of fuel injectors. See OUTPUT DIAGNOSTIC TEST MODE . All fuel injectors should 
audibly click. If any fuel injector does not click, go to next step. If all fuel injectors click, go to step 8 .  

2. Turn ignition off. Disconnect fuel injector harness connectors. Using DVOM, measure resistance between 

fuel injector terminals. See Fig. 24 . Resistance must be 14-18 ohms at room temperature (resistance 
should be greater than 14-18 ohms at engine operating temperature). If fuel injector resistance is okay, 
leave fuel injector harness connectors disconnected and go to next step. If fuel injector resistance is not 
okay, replace faulty fuel injector(s). See FUEL SYSTEM in appropriate REMOVAL, OVERHAUL & 
INSTALLATION article. After repairs, erase DTC memory. Verify repair. Test is complete. Perform 
ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

3.  

Turn ignition on. Using LED equipped test light connected to engine ground and with all fuel injector 
harness connectors disconnected, probe each fuel injector harness connector terminal No. 1. See Fig. 25 . 
Using ignition switch, operate starter, LED must illuminate. Repeat test at each fuel injector harness 
connector. If test light does not illuminate at each fuel injector harness connector terminal No. 1, go to 
next step. If test light illuminates at each fuel injector harness connector terminal No. 1, leave fuel 
injector harness connectors disconnected and go to step 5 .  

4. Check resistance between terminal No. 1 of fuel injector harness connector that does not illuminate and 

fuel pump relay. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in 
ELECTRICAL. Repair as necessary. After repairs, erase DTC memory. Verify repair. Test is complete. 
Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

5. With all fuel injector harness connectors disconnected, connect LED equipped test light between fuel 

NOTE:

Output Diagnostic Test Mode is used when using Scan Tools VAG 1551/1552 or 
VAS 5051/5052, always continue with output diagnostic test mode until last 
component in output diagnostic test mode test sequence has been checked. 
Follow scan tool manufacturer's instructions. 

NOTE:

When using scan tool to activate fuel injectors, they are barely audible. 
Use mechanics stethoscope if necessary. 

NOTE:

DO NOT check fuel injector voltage with engine running or fuel injector 
harness connectors installed on fuel injectors. Test light may not go out 
completely, but should dull and get brighter during activation. 

 

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 8:49:56 AM

Page 71 

© 2004 Mitchell Repair Information Company, LLC. 

 

 

 

 

 

 

 

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