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
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
NOTE:
No resistance specification for HO2S heater circuit is given by
manufacturer.
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
Helpmelearn Repair Manuals
Wednesday, December 14, 2005 8:44:45 AM
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© 2004 Mitchell Repair Information Company, LLC.