Jetta III L4-2.0L (ABA) (1995)
/Page-216001.png)
Oxygen Sensor: Technical Service Bulletins
Heated Oxygen Sensor - Troubleshooting
Group: 24
Number: 95-04
Date: Aug. 4, 1995
Subject:
Heated Oxygen Sensor, Troubleshooting
Model(s):
All Motronic Engine Management Systems m.y. 1993
Condition
A driveability complaint can lead to unnecessary replacement of the Heated Oxygen Sensor (H02S).
The following customer complaints and or observations may indicate a possible H02S problem.
^
Hesitation
^
Excessive visible exhaust smoke
^
Stalling and poor idle quality
^
CO outside specified range
^
Malfunction Indicator Lamp (MIL) Check Engine Light ON.
^
VAG 1551 Scan Tool displays, sensor malfunction
^
VAG 1551 Scan Tool displays, mixture control adjustment Diagnostic Trouble Code (DTC).
Oxygen sensor related complaints can be caused by:
^
Incorrect wiring combinations
^
Broken wires
^
Corroded terminals
^
Oxygen sensor heater not being energized (heater Relay not operating properly or supply Voltage interruption to sensor)
^
Contaminated sensor (e.g. Silicone, Antiseize compound etc.)
^
Malfunctioning Engine Coolant sensor (could cause the same complaints as Oxygen sensor)
^
Empty fuel tank or interrupted fuel supply
^
Vacuum leak or large exhaust leak upstream of the 02 sensor
^
Malfunctioning Engine Control Module
Service
Use the following steps to avoid unnecessary repairs when diagnosing suspected HO2S problems.
-
Make sure you have enough information by answering the following questions.
-
What is the symptom?
-
Under what conditions does it occur?
-
Is this the first repair for this complaint?
