Oxygen Sensor Heater For Oxygen Sensors Behind Three Way Catalytic Converter (TWC), Checking
Oxygen Sensor Heater For Oxygen Sensors Behind Three Way Catalytic Converter (TWC), Checking
Recommended special tools and equipment
- V.A.G 1526A multimeter
- V.A.G 1594A connector test kit
- V.A.G 1598/31 test box
Test requirements:
- Fuse for oxygen sensor heating OK
- Ground (GND) connections at engine and transmission OK
- Fuel Pump (FP) Relay OK; checking. Fuel Pump (FP) Relay -J17- and Activation, Checking
- Ignition switched off.
NOTE:
- Voltage for Oxygen Sensor (O2S) Heater 1 (behind Three Way Catalytic Converter (TWC)) -Z29- (bank 1, sensor 2) and Oxygen Sensor (O2S) Heater 2 (behind Three Way Catalytic Converter (TWC)) -Z30- (bank 2, sensor 2) is supplied via the Fuel Pump (FP) relay.
- Bank 1 = cylinder bank 1 in direction of travel, right; Bank 2 = cylinder bank 2 in direction of travel, left.
- When servicing terminals in harness connector of oxygen sensor, use only gold-plated terminals.
Procedure
- Disconnect electrical 4-pin harness connector -1- at right from Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130- and Oxygen Sensor (O2S) Heater 1 (behind Three Way Catalytic Converter (TWC)) -Z29- (bank 1, sensor 2).
- Remove coolant reservoir -2- (arrows)
- Disconnect electrical wire from Engine Coolant Level (ECL) Warning Switch -F66- and set aside coolant reservoir with coolant hoses -1- and -3- connected.
- Disconnect electrical 4-pin harness connector -4- at left from Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131- and Oxygen Sensor (O2S) Heater 2 (behind Three Way Catalytic Converter (TWC)) -Z30- (bank 2, sensor 2).
Checking internal resistance
- Connect multimeter between terminal 1 and 2 for resistance measurement.
- Specified value at room temperature: 6.4 to 47.5 Ohms
If specified value is not obtained:
- Replace respective oxygen sensor behind catalytic converter
If specified value is obtained:
Checking voltage supply
- Connect multimeter between terminal 1 and 2 for voltage measurement.
- Operate starter briefly.
- Specified value: approx. battery voltage
If there is no voltage:
- Connect multimeter for voltage measurement as follows:
Harness connector Terminal Measure to
1 Engine Ground (GND)
- Operate starter briefly.
- Specified value: approx. battery voltage
- Switch ignition off.
If there is no voltage again:
- Check wire connection from harness connector terminal 1 to Fuel Pump (FP) Relay -J17- via fuse for open circuit according to wiring diagram.
- Specified value: Wire resistance max 1.5 Ohms
- If necessary, repair wire connection.
If voltage supply is OK:
Check Ground (GND) activation
- Connect multimeter for voltage measurement as follows.
Harness connector Terminal Measure to
2 B+
- Operate starter briefly (engine can also start).
- Specified value: approx. battery voltage, possibly fluctuating
- Switch ignition off.
If specified value is not obtained:
- Connect test box to wiring harness of Engine Control Module (ECM); ECM is not connected. Test Box, Connecting For Wiring and Component Test
- Check the following wire connections for open circuit according to wiring diagram:
- Oxygen Sensor (O2S) Heater 1 (behind Three Way Catalytic Converter (TWC)) -Z29- bank 1 behind catalytic converter:
Harness connector Terminal Measure to
2 63
- Oxygen Sensor (O2S) Heater 2 (behind Three Way Catalytic Converter (TWC)) -Z30- bank 2 behind catalytic converter:
Harness connector Terminal Measure to
2 6
Specified value: Wire resistance max 1.5 Ohms
- Check wires for short circuit to B+ or Ground (GND).
- Specified value: Infinite Ohms (no continuity)
- If necessary, repair wire connection.
If no malfunctions are detected:
- Replace Engine Control Module (ECM).
Assembly is performed in reverse order of removal, note the following:
Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check DTC memory see "Mode 3: Check DTC memory". Mode 3: Check DTC Memory
2. If necessary, erase DTC memory see "Mode 4: Reset/erase diagnostic data". Mode 4: Reset/Erase Diagnostic Data
3. Generate readiness code. Readiness Code, Generating
- End diagnosis and switch ignition off.