Heated Oxygen Sensor Signal Wiring and Connections Checking

Heated Oxygen Sensor (HO2S) Signal Wiring And Wiring Connections, Checking


NOTE: Heated oxygen sensor signals are monitored by the On Board Diagnostic (OBD) system.


- Check Diagnostic Trouble Code (DTC) memory.

If HO2S malfunctions are indicated but O2S heating is OK:
- Disconnect oxygen sensor.







- Connect multimeter US 1119 (Fluke 83 or equivalent) at 2 VDC measuring range, and check voltage between harness connector terminals 3 and 4.
- Switch ignition on.
Specified value: 450 ± 50 mV (before TWC)

If voltage is not OK:
- Connect VAG1598/19 test box to Engine Control Module (ECM) harness connector. Refer "Scan Tool Testing/SCan Tool Connecting and Initial Checks/VAG1598/19 Test Box, Connecting" Testing and Inspection

- Check wiring connections for open circuit, short circuit to B+, and short circuit to Ground:


NOTE:
- Heated Oxygen Sensor (HO2S) -G39- (bank 1)
- Heated Oxygen Sensor (HO2S) 2 -G108- (bank 2)


HO2S or HO2S 2 VAG1598/19 test box socket (ECM terminal)
connector terminal
3 (G39) B20
4 (G39) B24
3 (G108) B21
4 (G108) B23







If wiring is OK:
- Replace Engine Control Module (ECM).