Diagnostic Mode 5: Check Oxygen Sensor Output Signals

Mode 5: Check Oxygen Sensor Output Signals

The static values of the oxygen sensors are indicated in this diagnostic mode.

The values of the individual oxygen sensor signal outputs must reach the specified value or must be within the min.- and max.- limits.

Test requirements:

- No DTCs in DTC memory; check DTC memory " Mode 3: Check DTC memory". Diagnostic Mode 3: Check DTC Memory
- Coolant temperature at least 80 degree C "Mode 1: Check measuring values "; "PID 05: Cooling fluid temperature". Diagnostic Mode 1: Check Measured Values

Work procedure
- Connect diagnostic tester. Diagnostic Tester, Connecting
- Start engine and let run at idle.
- In diagnostic function "33 - OBD", select "Mode 5: Check output of oxygen sensor signals".
- Via the following table, select the desired output of oxygen sensor signals according to Test ID (Test Identification), e.g. "01: Rich to lean sensor barrier voltage".
- Check specified values at idle.

NOTE:
- Bank 1 = cylinder bank 1 in direction of travel, right; Bank 2 = cylinder bank 2 in direction of travel, left.
- When selecting the diagnostic mode, the entry is always performed in "Bank 1 sensor 1".
- If either the VAG1551/1552 Scan Tool (ST) or VAS5051/5052 Vehicle Diagnostic, Testing and Information System is used for checking the output of oxygen sensor signals, the respective oxygen sensor can be selected by pressing button 1, 2, 5 and 6:
- Button 1 = Bank 1 sensor 1,
- Button 2 = Bank 1 sensor 2,
- Button 5 = Bank 2 sensor 1,
- Button 6 = Bank 2 sensor 2.

Test-ID 1) Diagnostic text
01: Rich to lean sensor barrier voltage
02: Lean to rich sensor barrier voltage
07: Minimum voltage at sensor for test cycle
08: Maximum voltage at sensor for test cycle
09: Time period between sensor shift procedures (half value)
48: "Rich"-shift of oxygen sensor regulation before catalytic converter via oxygen sensor regulation behind catalytic converter
49: "Lean"-shift of oxygen sensor regulation before catalytic converter via oxygen sensor regulation behind catalytic converter
50: Time period between sensor shift procedures

1) Test IDs that are not relevant are not listed.

- End diagnosis and switch ignition off.

Evaluation test-ID 01: Rich to lean sensor barrier voltage

Oxygen sensor Specified value
Bank 1, sensor 1 0.442 V
Bank 2, sensor 1 0.442 V
Bank 1, sensor 2 0.600 V
Bank 2, sensor 2 0.600 V

If specified value is not obtained:
- Replace respective oxygen sensor.

Evaluation test-ID 02:Lean to rich sensor barrier voltage

Oxygen sensor Specified value
Bank 1, sensor 1 0.442 V
Bank 2, sensor 1 0.442 V
Bank 1, sensor 2 0.625 V
Bank 2, sensor 2 0.625 V

If specified value is not obtained:
- Replace respective oxygen sensor.

Evaluation test-ID 07: Minimum voltage at sensor for test cycle

If the specified value is not reached:
- Short circuit to Ground (GND) in oxygen sensor or in wire.
- Check Oxygen Sensor (O2S) and oxygen sensor control before Three Way Catalytic Converter (TWC).
- Check Oxygen Sensor (O2S) and oxygen sensor control behind Three Way Catalytic Converter (TWC).

If the specified value is exceeded:
- Oxygen sensor not ready for operation
- Oxygen sensor heater faulty
- Test oxygen sensor heater before catalytic converter. Heater Check
- Test oxygen sensor heater behind catalytic converter. Heater Check

- Short circuit to B+ or open circuit in wiring in oxygen sensor or in wire.

- Check Oxygen Sensor (O2S) and oxygen sensor control before Three Way Catalytic Converter (TWC). Sensor and Sensor Control Check
- Check Oxygen Sensor (O2S) and oxygen sensor control behind Three Way Catalytic Converter (TWC). Sensor and Sensor Control Check

Evaluation test-ID 08: Maximum voltage at sensor for test cycle

If the specification is exceeded or not reached:

- Oxygen sensor not ready for operation
- Oxygen sensor heater faulty

- Test oxygen sensor heater before catalytic converter. Heater Check
- Test oxygen sensor heater behind catalytic converter. Heater Check

- Short circuit to Ground (GND) or open circuit in wiring in oxygen sensor or in wire.

- Check Oxygen Sensor (O2S) and oxygen sensor control before Three Way Catalytic Converter (TWC). Sensor and Sensor Control Check
- Check Oxygen Sensor (O2S) and oxygen sensor control behind Three Way Catalytic Converter (TWC). Sensor and Sensor Control Check

Evaluation test-ID 09: Time period between sensor shift procedures (half value)

If the specified value is exceeded:
- Short circuit to B+ or open circuit in wiring in oxygen sensor or in wire.
- Oxygen sensor faulty

- Check Oxygen Sensors (O2S) and oxygen sensor control before Three Way Catalytic Converter (TWC). Sensor and Sensor Control Check
- Check Oxygen Sensor (O2S) and oxygen sensor control behind Three Way Catalytic Converter (TWC). Sensor and Sensor Control Check

- Mixture too lean

- Check fuel pressure regulator and residual pressure. With Generic Scan Tool
- Check fuel injectors. With Generic Scan Tool
- Check intake system for leaks (false air). Testing and Inspection
- Check Fuel Pump (FP). Fuel Pump (FP), Electrical Testing
- Check exhaust system for proper seal. Testing and Inspection
- Check Secondary Air Injection (AIR) system for proper seal. Testing and Inspection
- Check vacuum lines for proper seal.

Evaluation test-ID 49: "Lean"-shift of oxygen sensor regulation before catalytic converter via oxygen sensor regulation behind catalytic converter

If the specified value is exceeded:
- Short circuit to Ground (GND) or open circuit in wiring in oxygen sensor or in wire.
- Oxygen sensor faulty

- Check Oxygen Sensors (O2S) and oxygen sensor control before Three Way Catalytic Converter (TWC). Oxygen Sensors Before Catalytic Converter
- Check Oxygen Sensor (O2S) and oxygen sensor control behind Three Way Catalytic Converter (TWC). Oxygen Sensor After Catalytic Converter

- Mixture too rich

- Check fuel pressure regulator and residual pressure. With Generic Scan Tool
- Check fuel injectors. With Generic Scan Tool
- Check Evaporative Emission (EVAP) canister purge regulator valve -N80-. With Generic Scan Tool

Evaluation test-ID 50: Time period between sensor shift procedures

If the specified value is not reached:
- Short circuit in oxygen sensor or in wire:

- Check Oxygen Sensor (O2S) and oxygen sensor control before Three Way Catalytic Converter (TWC). Oxygen Sensors Before Catalytic Converter

If the specified value is exceeded:
- Oxygen sensor faulty
- Check Oxygen Sensor (O2S) and oxygen sensor control before Three Way Catalytic Converter (TWC). Oxygen Sensor After Catalytic Converter

- Oxygen sensor is aged

- Replace respective oxygen sensor before catalytic converter.

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1 - Check DTC memory "Mode 3: Check DTC memory". Diagnostic Mode 3: Check DTC Memory
2 - If necessary, erase DTC memory "Mode 4: Reset/erase diagnostic data". Diagnostic Mode 4: Reset/Erase Diagnostic Data
3 - Generate readiness code. Readiness Code, Generating

- End diagnosis and switch ignition off.