Operation CHARM: Car repair manuals for everyone.
Home >> Audi >> 1995 >> Cabriolet V6-2.8L (AAH) >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Oxygen Sensor >> Testing and Inspection >> Checking Oxygen Sensor Heating
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Checking Oxygen Sensor Heating

PROCEDURE
- Disconnect Heated Oxygen Sensor (HO2S) harness connector on right or left cylinder bank.

2 Pin Harness Connector:





- Connect multimeter (Fluke 83 or equivalent) between connector terminals 1 (GND), and 2 (B+).
- Start engine and let idle.
^ Specified value: approx. 12-14 volts.

If specified values are not obtained:
- Check HO2S fuse S28 (red fuse holder, engine) in central electrical system.
- Check continuity in wiring from connector terminal 1 to fuse using wiring diagram.
^ Specified value: maximum 0.5 ohms.
- Check continuity in wiring from connector terminal 2 to GND.
^ Specified value: maximum 0.5 ohms.
- Check fuel pump relay.

If the specified values are obtained:
- Connect additional test harness VAG 1315A/1 into 2-pin HO2S connector.
- Switch multimeter to 10 amp (DC) measuring range and connect (connect test harness to 10 amp connector).
- Start engine and let idle.
^ Specified reading: 0.5-3.0 amps.
^ Current (amperage) decreases as sensor temperature increases.

If specified reading is not obtained:
- Replace heated oxygen sensor.
pro multis · About Operation CHARM