Sensor and Sensor Control Check
Oxygen Sensors And Oxygen Sensor Control Before Catalytic Converter, Checking
Special tools and equipment
- VAG 1526 A
- VAG 1594 A
- VAG 1598/31
- VAS 5051 with VAS 5051/1
Test requirements
- No leaks in exhaust system.
- Engine coolant temperature at least 80 degree C See display group 004, display zone 3.
Test sequence
- Connect vehicle diagnostic, testing and information system VAS 5051 and select vehicle system "01 -Engine electronics" in selection. Engine must be running at idling speed. Connecting VAS 5051 Scan Tool
Display on VAS 5051:
- Under -1- select diagnostic function "04 - Basic setting".
Display on VAS 5051:
1 - Enter display group.
- Enter "030" for "display group number 030" in zone -2- and confirm entry by pressing -Q- button.
Display on VAS 5051:
- Check specifications in display zones -1- and -3-.
NOTE:
- By increasing the engine speed the specified values are achieved quickly.
- The "oxygen sensor status" indicates the condition of the oxygen sensor control and the oxygen sensors.
Display Group 030:
Significance of 3-digit readout of display group 030
Display Zone 1 - 4:
Display on VAS 5051:
- Only continue with test if displays have reached "111" in display zones -1-and -3- at least once.
- Press <- button.
Checking Oxygen Sensor Learned Values And Oxygen Sensor Control
Display on VAS 5051:
1 - Enter display group
- Enter "032" for "display group number 032" in zone -2- and confirm entry by pressing -Q- button.
- Check values in display zones -1- to -4-.
Display Group 032:
- Press <- button.
Display on VAS 5051:
1 - Enter display group.
- Enter "033" for "display group number 033" in zone -2- and confirm entry by pressing -Q- button.
Display on VAS 5051:
- Activate basic setting by pressing -A- button.
- Check indication in display fields -1- to -4-.
Display Group 033:
- Exit function "04 - Basic setting" by pressing <- button.
Continuation
If specification is not obtained in display zone 1 or display zone 3, or if the value does not fluctuate by at least 2%:
- Perform drive test to free oxygen sensors from any possible residues and repeat test.
If the specified result is not achieved in display zones 1 or 3, or if the value does not fluctuate by at least 2%, even after the test drive:
- Check basic voltage.
- Check oxygen sensor heating before catalytic converter. Heater Check
- Check oxygen sensor before catalytic converter for aging. Aging Check
Evaluating display group 032
Display 1/3 Or 2/4:
Evaluating display group 032
Display Zone 1/3 Or 2/4:
Evaluating display group 033
Display Zone 2/4:
Checking basic voltage
Test requirements:
- Fuse for oxygen sensors OK.
- Disconnect 6-pin connector of relevant oxygen sensor before catalytic converter.
- Connect multimeter between terminals 1 and 5 to measure voltage.
- Switch ignition on.
- Specified value: 0.400 to 0.500 V
- Switch ignition off.
If specified value is not obtained:
- Check oxygen sensor wiring:
Bank 1 or Bank 2
If specified value is not obtained:
- Replace relevant oxygen sensor before catalytic converter.
Check oxygen sensor wiring, bank 1, sensor 1, Heated Oxygen Sensor (HO2S) -G39-
- Disconnect 6-pin connector of bank 1, Heated Oxygen Sensor (HO2S) -G39-.
- Connect test box VAG 1598/31 to wiring harness for engine control module; engine control module must not be connected. Wiring and Component Testing Using VAG1598/31 Test Box
- Test for open circuit in following wiring connections.
Connector Test box VAG 1598/31
terminal Socket
1 70
2 71
3 51
4 52
- Repair open circuit, if necessary.
- Check for shorts between two wires.
If no wiring malfunction is detected:
- Replace engine control module.
Check oxygen sensor wiring, bank 2, sensor 1, Heated Oxygen Sensor (HO2S) 2 -G108-
- Disconnect 6-pin connector of bank 2, Heated Oxygen Sensor (HO2S) 2 -G108-.
- Connect test box VAG1598/31 to wiring harness for engine control module; engine control module must not be connected. Wiring and Component Testing Using VAG1598/31 Test Box
- Test for open circuit in following wiring connections.
Connector Test box VAG 1598/31
terminal Socket
1 13
2 14
5 12
6 15
- Repair open circuit, if necessary.
- Check for shorts between two wires.
If no wiring malfunction is detected:
- Replace engine control module.