Volkswagen New Beetle. Manual - part 1815

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. 4 and test box socket No. 5. See Fig. 22 . 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 .

Fig. 21: Identifying Heated Oxygen Sensor Terminals (G39) - Upstream 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)

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Fig. 22: Identifying Heated Oxygen Sensor Harness Connector Terminals - Upstream TWC
Courtesy of VOLKSWAGEN UNITED STATES, INC.

DTC P0133/16517 & P0134/16518: HO2S UPSTREAM TWC

Code Definition

DTC P0133/16517
HO2 Sensor (G39) Upstream TWC - Signal Too Slow (Aging)

DTC P0134/16518
HO2 Sensor (G39) Upstream TWC - No Activity (Aging)

Test Requirements

2003 Volkswagen New Beetle GLS

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

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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 34". 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-S1 OK". If scan tool does not display "B1-S1 OK", go to next
step. If scan tool displays "B1-S1 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 .

DTC P0136/16520, P0137/16521 & P0138/16522: HO2S DOWNSTREAM TWC

Code Definition

DTC P0136/16520
HO2 Sensor (G130) Downstream TWC - Circuit Malfunction

DTC P0137/16521
HO2 Sensor (G130) Downstream TWC - Voltage Too Low

NOTE:

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

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 .

2003 Volkswagen New Beetle GLS

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

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DTC P0138/16522
HO2 Sensor (G130) Downstream TWC - Voltage Too High

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) control signal activation. HO2S control signal should be activated. Use scan tool to check
downstream HO2S readiness. HO2S should be operationally ready. Observe scan tool in downstream
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 P0141/16525: HO2 SENSOR
(G130) DOWNSTREAM TWC, HEATING ELEMENT CIRCUIT MALFUNCTION .

Using scan tool, check downstream HO2S control signal switching voltage. Downstream HO2S voltage
should vary in very small increments, approximately 0.1 volt or less (e.g. 0.6 to 0.7 volt within
specification range of 0.1 to 0.9 volt). If downstream HO2S voltage remains constant at any of the
voltages identified in DOWNSTREAM HO2S CONTROL SIGNAL SWITCHING VOLTAGE table,
go to step 5 . If HO2S does not remain constant at any of the voltages identified in DOWNSTREAM
HO2S CONTROL SIGNAL SWITCHING VOLTAGE table, go to next step. If downstream HO2S

NOTE:

If no fault is found when using this Test Procedure, check downstream HO2S
(G130) heater. See DTC P0141/16525: HO2 SENSOR (G130) DOWNSTREAM
TWC, HEATING ELEMENT CIRCUIT MALFUNCTION .

NOTE:

Downstream HO2S (G130) control signal activation may only occur above
1500 RPM.

NOTE:

Downstream HO2S voltage does not fluctuate in the same manner as
upstream HO2S. Downstream HO2S voltage may vary in very small
increments, approximately 0.1 volt or less (e.g. 0.6 to 0.7 volt), within a
specification range of 0.1 to 0.9 volt. When engine, HO2Ss and catalytic
converter are in good working order, downstream HO2S voltage may not
switch at all in a defined RPM range (e.g.: 1500 RPM). See Fig. 23 .

2003 Volkswagen New Beetle GLS

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

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