3.
Is the problem found?
▶ Repair the trouble causing part and go to "Verification of Vehicle Repair".
▶ Go to "Power Circuit Inspection".
O2 sensor installed at exhaust manifold is linear O2 sensor 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 λ-value from linear O2 sensor to 1.0.
Lean air-fuel mixture(1.0＜λ＜1.1) : ECM supplies pumping current to O2 sensor (+pumping current) and activates it for O2 sensor to have the characteristic at λ=1.0 (0.0 pumping current). With the value of pumping current supplied to O2 sensor, ECM detects O2 density of exhaust gas.
Rich air-fuel mixture(0.9＜λ＜1.0) : ECM takes away pumping current from O2 sensor (-pumping current) and deactivates it for O2 sensor to have the characteristic at λ=1.0 (0.0 pumping current). With the value of pumping current taken away from O2 sensor, ECM detects O2 density of exhaust gas.
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 O2 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, O2 sensor temp. is measured and O2 sensor heater operation varies based on the data.
P0032 is set when short to battery in O2 sensor control circuit is detected for more than 2.0 sec. at O2 sensor heater control condition. This code is due to 1)short to battery in heater control circuit or 2)O2 sensor heater internal open.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy | ● Voltage monitoring | ● O2 sensor heater circuit ● O2 sensor component | ||
Enable Conditions | ● Engine running | |||
ThresholdValue | ● Short to battery in O2 sensor heater control circuit | |||
DiagnosticTime | ● 2.0 sec. | |||
Fail Safe | Fuel Cut | NO | ||
EGR Off | NO | |||
Fuel Limit | NO | |||
MIL | NO | |||
Temperature (℃) | O2 sensor heater resistance(Ω) | Temperature (℃) | O2 sensor heater resistance(Ω) | O2 sensor heater control Hz |
20 | 9.2 | 400 | 17.7 | 100 Hz |
100 | 10.7 | 500 | 19.2 | |
200 | 13.1 | 600 | 20.7 | |
300 | 14.6 | 700 | 22.5 |
Electrical systems consist of a lot of harness and connectors, poor connection of terminals can cause various problems and damge of component.
Perform checking procedure as follows.
Check damage of harness and terminals : Check terminals for contact resistance, corrosion and deformation.
Check connecting condition of ECM and component connector : Check terminal seperation, damage of locking device and connecting condition between terminal and wiring.
Disconnect the pin which requires checking at male connector and insert it to the terminal at female connector for checking connecting condition. ( after checking, reconnect the pin at correct position. )
Is the problem found?
▶ Repair the trouble causing part and go to "Verification of Vehicle Repair".
▶ Go to "Power Circuit Inspection".
IG KEY "OFF", ENGINE "OFF".
Disconnect O2 sensor connector.
IG KEY "ON".
Measure the voltage of O2 sensor connector terminal 2.
Specification : 11.0V~13.0V ( Main relay ON power )
Is the measured voltage within the specification?
▶ Go to "Control Circuit Inspection".
▶ Repair open in Main relay power circuit and E/R FUSE ＆ RELAY BOX 10A SNSR fuse and go to "Verification of Vehicle Repair".
Check O2 sensor heater control circuit voltage
IG KEY "OFF", ENGINE "OFF".
Disconnect O2 sensor connector.
IG KEY "ON".
Measure the voltage of O2 sensor connector terminal 5.
Specification : 2.0V~2.5V
Is the measured voltage within the specification?
▶ Go to "Component Inspection".
▶ No voltage is detected : Go to "2. Check open in O2 sensor heater control circuit" as follows.
▶ High voltage is detected : Repair short to battery in control circuit and go to "Verification of Vehicle Repair".
Check open in O2 sensor heater control circuit
IG KEY "OFF", ENGINE "OFF".
Disconnect O2 sensor connector and ECM connector.
Check continuity between O2 sensor connector terminal 5 and ECM connector terminal 51.
Specification : Continuity (below 1.0Ω )
Is the measured resistance within the specification?
▶ Repair short to ground in control circuit and go to "Verification of Vehicle Repair".
▶ Repair open in O2 sensor heater control circuit and go to "Verification of Vehicle Repair".
Check O2 sensor component heater coil resistance
IG KEY "OFF", ENGINE "OFF".
Disconnect O2 sensor connector.
Check continuity between O2 sensor component connector 2 and 5.
Specification : Refer to "Specification" of "General Information"
Is the measured resistance within the specification?
▶ Go to "Verification of Vehicle Repair".
▶ Replace O2 sensor and go to "Verification of Vehicle Repair".
After a repair, it is essential to verify that the fault is corrected.
After connecting Scantool select "DIAGNOSTIC TROUBLE CODES(DTCs)" mode.
Clear recorded DTC using Scantool.
Drive the vehicle within DTC "Enable conditions" in "General information".
After selecting "DIAGNOSTIC TROUBLE CODES(DTCs)" mode and check if DTC is recorded again.
Are any DTCs recorded ?
▶ Go to the DTC guide of recorded NO. in Scantool.
▶ System operates within specification.
