1. Oxygen Sensor (S1)
Lambda sensor installed at exhaust manifold is planar ZrO2 dual cell type and it senses O2 density of exhaust gas for accurate EGR control through fuel correction. It also limits smoke which is generated by reach air-fuel mixture at engine maximum loading condition. ECM controls pumping current in order to fit ?-value from linear O2 sensor to 1.0.
Lean air-fuel mixture(1.0
Rich air-fuel mixture(0.9
This performance is the most active and fast at normal operating temp.(450?~600?) thus, in order to reach normal operating temp. and last at that temp., heater(heating coil) is integrated with Lambda sensor.
Heater coil is controlled by ECM as PWM. the resistance of heater coil is low when coil is cold thus, current through it increases while resistance is high when coil is hot thus, current decreases. With this principle, Lambda sensor temp. is measured and Lambda sensor heater operation varies based on the data.
ECM assumes the correction resistance circuit is open and shows P2626 when upstream O2 sensor is higher than 4.8V under the fuel cut condition.
Item
Detecting Condition
Possible Cause
DTC Strategy
Circuit continuity check
Poor connection
Open or short power/ground in signal circuit
S1
Enable Conditions
Fuel cut condition
Threshold Value
Sensor voltage >4.8V
Diagnostic Time
2 sec
MIL ON Condition
2 driving cycle
Waveform of sensor Current Pump at IG KEY "ON" and Engine running. It fluctuates between 2V and 3V periodically.
Waveform of sensor Vertual Ground Output at IG KEY "ON" and Engine running. 2.5V is displayed.
Waveform of sensor Current Adjust at IG KEY "ON" and Engine running. It fluctuates between 2V and 3V periodically. Waveform of sensor Nernst Voltage at IG KEY "ON" and Engine running. 2.9V is displayed.