P003612, P003614, P005612, P005614, P102A9E, P105A9E

DTC Code	DTC Name
P003612	HO2S Heater Control Circuit Bank 1 Sensor 2 Circuit Short to Battery
P003614	HO2S Heater Control Circuit Bank 1 Sensor 2 Circuit Short to Ground or Open
P005612	HO2S Heater Control Bank 2 Sensor 2 Circuit Short to Battery
P005614	HO2S Heater Control Bank 2 Sensor 2 Circuit Short to Ground or Open
P102A9E	O2 Sensor Heater Performance Bank 1 Sensor 2 Stuck On
P105A9E	O2 Sensor Heater Performance Bank 2 Sensor 2 Stuck On

DESCRIPTION

In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a TWC (Three-Way Catalytic Converter) is used. For the most efficient use of the TWC, the air fuel ratio must be precisely controlled so that it is always close to the stoichiometric air fuel level. For the purpose of helping the ECM to deliver accurate air fuel ratio control, a heated oxygen sensor is used.

The heated oxygen sensor is located behind the TWC, and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with the heater that heats the sensing portion, it is possible to detect the oxygen concentration even when the intake air volume is low (the exhaust gas temperature is low).

When the air fuel ratio becomes lean, the oxygen concentration in the exhaust gas is high. The heated oxygen sensor informs the ECM that the post-TWC air fuel ratio is lean (low voltage, i.e. less than 0.45 V).

Conversely, when the air fuel ratio is richer than the stoichiometric air fuel level, the oxygen concentration in the exhaust gas is low. The heated oxygen sensor informs the ECM that the post-TWC air fuel ratio is rich (high voltage, i.e. higher than 0.45 V). The heated oxygen sensor has the property of changing its output voltage drastically when the air fuel ratio is close to the stoichiometric level.

The ECM uses the supplementary information from the heated oxygen sensor to determine whether the air fuel ratio after the TWC is rich or lean, and adjusts the fuel injection duration accordingly. Thus, if the heated oxygen sensor is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in the primary air fuel ratio control.

Tech Tips

When any of these DTCs are stored, the ECM enters fail-safe mode. The ECM turns off the heated oxygen sensor heater in fail-safe mode. Fail-safe mode continues until the engine switch is turned off.
The heated oxygen sensor heater circuit uses a relay on the +B side of the circuit.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory	Note
P003612	HO2S Heater Control Circuit Bank 1 Sensor 2 Circuit Short to Battery	Heated oxygen sensor heater current reaches high limit (1 trip detection logic).	Short in heated oxygen sensor (bank 1 sensor 2) heater circuit Heated oxygen sensor (bank 1 sensor 2) ECM	Comes on	DTC stored	SAE Code: P0038
P003614	HO2S Heater Control Circuit Bank 1 Sensor 2 Circuit Short to Ground or Open	Heated oxygen sensor heater current is the specified value or less while the heater is operating (1 trip detection logic).	Open or short in heated oxygen sensor (bank 1 sensor 2) heater circuit Heated oxygen sensor (bank 1 sensor 2) ECM	Comes on	DTC stored	SAE Code: P0037
P005612	HO2S Heater Control Bank 2 Sensor 2 Circuit Short to Battery	Heated oxygen sensor heater current reaches high limit (1 trip detection logic).	Short in heated oxygen sensor (bank 2 sensor 2) heater circuit Heated oxygen sensor (bank 2 sensor 2) ECM	Comes on	DTC stored	SAE Code: P0058
P005614	HO2S Heater Control Bank 2 Sensor 2 Circuit Short to Ground or Open	Heated oxygen sensor heater current is the specified value or less while the heater is operating (1 trip detection logic).	Open or short in heated oxygen sensor (bank 2 sensor 2) heater circuit Heated oxygen sensor (bank 2 sensor 2) ECM	Comes on	DTC stored	SAE Code: P0057
P102A9E	O2 Sensor Heater Performance Bank 1 Sensor 2 Stuck On	Heated oxygen sensor heater current is higher than the specified value while the heater is not operating (1 trip detection logic).	Short in heated oxygen sensor (bank 1 sensor 2) heater circuit Heated oxygen sensor (bank 1 sensor 2) ECM	Comes on	DTC stored	SAE Code: P102D
P105A9E	O2 Sensor Heater Performance Bank 2 Sensor 2 Stuck On	Heated oxygen sensor heater current is higher than the specified value while the heater is not operating (1 trip detection logic).	Short in heated oxygen sensor (bank 2 sensor 2) heater circuit Heated oxygen sensor (bank 2 sensor 2) ECM	Comes on	DTC stored	SAE Code: P105D

MONITOR DESCRIPTION

The sensing portion of the heated oxygen sensor has a zirconia element which is used to detect the oxygen concentration in the exhaust gas. If the zirconia element is at the appropriate temperature, and the difference between the oxygen concentrations surrounding the inside and outside surfaces of the sensor is large, the zirconia element generates voltage signals. In order to increase the oxygen concentration detecting capacity of the zirconia element, the ECM supplements the heat from the exhaust with heat from a heating element inside the sensor.

Heated Oxygen Sensor Heater Range Check (P003612, P003614, P005612, P005614, P102A9E and P105A9E):
- The ECM monitors the current applied to the heated oxygen sensor heater to check the heater for malfunctions.
  
  If the heater current is outside the normal range, the signal transmitted by the heated oxygen sensor becomes inaccurate. When the current in the heated oxygen sensor heater is outside the normal operating range, the ECM interprets this as a malfunction in the sensor heater and stores a DTC.

MONITOR STRATEGY

Required Sensors/Components	Heated oxygen sensor (sensor 2) heater
Frequency of Operation	Continuous

TYPICAL ENABLING CONDITIONS

Time after heater on

10 seconds or more

CONFIRMATION DRIVING PATTERN

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG) [A].
Turn the GTS on.
Start the engine and idle it for 5 minutes or more [B].
With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 3000 rpm for 1 minute [C].
Idle the engine for 5 minutes or more [D].
Enter the following menus: Powertrain / Engine / Trouble Codes [E].
Read the pending DTCs.
Tech Tips
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P003612, P003614, P005612, P005614, P102A9E or P105A9E.

Check the DTC judgment result.

GTS Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions

Tech Tips

If the judgment result is NORMAL, the system is normal.
If the judgment result is ABNORMAL, the system has a malfunction.
If the judgment result is INCOMPLETE, perform steps [B] through [E] again.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

Note

Inspect the fuses for circuits related to this system before performing the following procedure.

Tech Tips

Bank 1 refers to the bank that includes the No. 1 cylinder*.

*: The No. 1 cylinder is the cylinder which is farthest from the transaxle.
Bank 2 refers to the bank that does not include the No. 1 cylinder.
Sensor 1 refers to the sensor closest to the engine assembly.
Sensor 2 refers to the sensor farthest away from the engine assembly.
Refer to "Data List / Active Test" [O2 Sensor Heater B1S2, O2 Sensor Heater Current Value B1S2, O2 Sensor Heater B2S2 and O2 Sensor Heater Current Value B2S2].

Click here
When the values for the Data List item O2 Sensor Heater Current Value B1S2 and O2 Sensor Heater Current Value B2S2 are not 0 A, the heater is on.
Change the fuel injection volume using the Control the Injection Volume for A/F Sensor function provided in the Active Test and monitor the heated oxygen sensor output voltage Click here. If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.
Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

Inspect the heated oxygen sensor.

Click here

Result

Proceed to
OK
NG

NG

REPLACE HEATED OXYGEN SENSOR Click here

OK

CHECK TERMINAL VOLTAGE (POWER SOURCE OF HEATED OXYGEN SENSOR)

*a

Front view of wire harness connector

(to Heated Oxygen Sensor)

*b

Bank 1

*c

Bank 2

-

Disconnect the heated oxygen sensor connector.
Turn the engine switch on (IG).

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Condition	Specified Condition
K38-2 (+B) - Body ground	Engine switch on (IG)	11 to 14 V
D104-2 (+B) - Body ground	Engine switch on (IG)	11 to 14 V

Result

Proceed to
OK
NG

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI-MAIN RELAY - HEATED OXYGEN SENSOR)

OK

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)

Disconnect the heated oxygen sensor connector.
Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
K38-1 (HT1B) - D110-50 (HT1B)	Always	Below 1 Ω
D104-1 (HT2B) - D110-16 (HT2B)	Always	Below 1 Ω
K38-1 (HT1B) or D110-50 (HT1B) - Body ground and other terminals	Always	10 kΩ or higher
D104-1 (HT2B) or D110-16 (HT2B) - Body ground and other terminals	Always	10 kΩ or higher

Result

Proceed to
OK
NG

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

CLEAR DTC

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTC.

Powertrain > Engine > Clear DTCs

Turn the engine switch off and wait for at least 30 seconds.

Result

Proceed to
NEXT

CHECK WHETHER DTC OUTPUT RECURS (DTC P003612, P003614, P005612, P005614, P102A9E OR P105A9E)

Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine / Trouble Codes.

Read the DTCs.

Powertrain > Engine > Trouble Codes

Result

Result	Proceed to
DTCs are not output	A
DTC P003612, P003614, P005612, P005614, P102A9E or P105A9E is output	B

A

CHECK FOR INTERMITTENT PROBLEMS Click here

B

REPLACE ECM Click here

SFI SYSTEM, Diagnostic DTC:P003612, P003614, P005612, P005614, P102A9E, P105A9E