Oxygen sensor signal (B1-S1), mode 5

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 1999 Volkswagen Jetta, 1999 Volkswagen GTI, 1998 Volkswagen Jetta, 1998 Volkswagen GTI, and 1997 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: When a Heated Oxygen Sensor (HO2S) malfunction is stored, use mode 5 to check the HO2S signal output, to see whether the HO2S before three way catalytic converter is within specification, or whether another malfunction is present, e.g. the HO2S after three way catalytic converter is causing an O2S control malfunction.

The points 01 to 09 in Fig 1 represent:

01 - Rich/lean threshold voltage (constant value)

02 - Lean/rich threshold voltage (constant value)

03 - Lower voltage for calculating switching period

04 - Upper voltage for calculating switching period

05 - Calculated rich/lean switching time

06 - Calculated lean/rich switching time

07 - Minimum test voltage

08 - Maximum test voltage

09 - Time between threshold voltages

Fig 1: Identifying Oxygen Sensor Signal (B1-S1)

Press --> button -5- to select mode 5 oxygen sensor signal (B1-S1).

Display will appear as shown: Test ID 01

Fig 2: Identifying Scan Tool Display - Oxygen Sensor Signal (B1-S1), Mode 5 (1 Of 5)

Rich/lean threshold voltage: Standard value 0.445 volts

Press --> button.

Display will appear as shown: Test ID 02

Fig 3: Identifying Scan Tool Display - Oxygen Sensor Signal (B1-S1), Mode 5 (2 Of 5)

Lean/rich threshold voltage: constant value 0.445 volts
If constant value is not obtained, the HO2S is faulty

Press --> button.

For the following three HO2S signal values shown in HO2S SIGNAL VALUES table are always displayed:

HO2S SIGNAL VALUES

1st value = Minimum value

2nd value = Actual value

3rd value = Maximum value

NOTE: The displayed Min. and Max. values are constant and do not change. The actual value is displayed as a constant. It will only change when during the test the HO2S supplies a greater or smaller signal.

Display will appear as shown: Test ID 07

Fig 4: Identifying Scan Tool Display - Oxygen Sensor Signal (B1-S1), Mode 5 (3 Of 5)

Minimum test voltage
If the actual value is below 0.148 volts, there is a short to ground.
When the actual value exceeds 0.4 volts, the malfunction could be the HO2S is not at working temperature, sensor heating is faulty, wiring open circuit to HO2S or a short circuit to positive (B+).

Press --> button.

Display will appear as shown: Test ID 08

Fig 5: Identifying Scan Tool Display - Oxygen Sensor Signal (B1-S1), Mode 5 (4 Of 5)

Maximum test voltage
If the actual value is above 1.078 volts, there is a short circuit to positive (B+) in the wire to HO2S
If the actual value is below 0.598 volts, the malfunction could be a HO2S not reaching proper operating temperature, faulty O2S heating or an open circuit in the HO2S wiring.

Press --> button.

Display will appear as shown: Test ID 09

Fig 6: Identifying Scan Tool Display - Oxygen Sensor Signal (B1-S1), Mode 5 (5 Of 5)

Display will appear as shown: Test ID 09 The display shows the time between the threshold voltages
If the actual value is below the minimum time of 0.04 seconds, there is a short circuit
If the actual value exceeds the maximum time of 1.20 seconds, the malfunction could be due to an aged, lazy or contaminated oxygen sensor.

Press -C- button to exit the program sequence.