Volkswagen New Beetle. Manual - part 1816

voltage is okay (voltage is fairly constant, but does not match voltages identified in DOWNSTREAM
HO2S CONTROL SIGNAL SWITCHING VOLTAGE table), test is complete. Erase DTC memory.
Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .

DOWNSTREAM HO2S CONTROL SIGNAL SWITCHING VOLTAGE

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

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

5. Turn ignition off. Raise vehicle and remove HO2 sensors protective cover. Disconnect downstream

HO2S (G130) harness connector (Brown 4-pin). See Fig. 14 . Go to next step.

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

connector. See Fig. 16 . 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. 16 .

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

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 any resistance measurement is not okay, or a short
circuit exists, repair circuit(s), as necessary. 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 . After
repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST
DRIVE RELEARN PROCEDURE .

Downstream HO2S Voltage

Possible Fault

(1)

0.0

Possible Short To Ground

1.1

Possible Short To B+

0.4-0.5

Possible Open Circuit (ECM Supplied Basic Voltage)

(1)

Voltages identified in this table indicate a fault with downstream HO2S switching
voltage.

2003 Volkswagen New Beetle GLS

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

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Page 64

Fig. 23: Identifying HO2S Patterns
Courtesy of VOLKSWAGEN UNITED STATES, INC.

DTC P0139/16523 & P0140/16524: HO2S DOWNSTREAM TWC

2003 Volkswagen New Beetle GLS

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

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Code Definition

DTC P0139/16523
HO2 Sensor (G39) Downstream TWC - Signal Too Slow (Aging)

DTC P0140/16524
HO2 Sensor (G39) Downstream TWC - No Activity (Aging)

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 .

Connect scan tool. See RETRIEVING DIAGNOSTIC TROUBLE CODES . If using Scan Tool VAG
1551/1552 or VAS 5051/5052, go to next step. If using generic scan tool, follow scan tool manufacturer's
instructions, check aging of upstream HO2S. If scan tool indicates aging of upstream HO2S is not okay,
go to step 4 . If scan tool indicates aging of upstream HO2S is okay, erase DTC memory. Test is
complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .

3. 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 "system in basic setting 43". Using accelerator pedal prop
manually set engine speed to 2300-2500 RPM. Maintain engine speed of 2300 to 2500 RPM until scan
tool display jumps from "Test off" to "Test on". Continue to maintain engine speed of 2300 to 2500 RPM
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, replace downstream HO2S. After repairs, erase DTC
memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE
RELEARN PROCEDURE .

NOTE:

Manufacturer recommends using Scan Tool VAG 1551/1552 or VAS
5051/5052.

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

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

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Wednesday, December 14, 2005 8:49:55 AM

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

Test Requirements

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 .

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. SeeENGINE 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

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 8:49:55 AM

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