DESCRIPTION The air fuel
ratio sensor (sensor 2) generates current that corresponds to the actual
air fuel ratio. This sensor current is used to provide the ECM with
feedback so that it can control the air fuel ratio. The ECM determines
the deviation from the stoichiometric air fuel ratio level, and
regulates the fuel injection duration. If the air fuel ratio sensor
(sensor 2) malfunctions, the ECM is unable to control the air fuel ratio
accurately. The air fuel ratio sensor (sensor
2) is a cup type sensor and uses a zirconia element for the sensor
element. The zirconium element is made of platinum coated zirconium and
includes an integrated heating element. The inner surface of the
zirconia element is exposed to the outside air and the outer surface of
it is exposed to the exhaust gas. The zirconia element generates a
voltage according to the oxygen concentration of the exhaust gas and
outside air. The air fuel ratio sensor (sensor 2) becomes very efficient
when heated. When the exhaust gas temperature is low, the sensor does
not generate useful voltage signals without supplementary heating.
Therefore, the air fuel ratio sensor (sensor 2) includes a heater to
heat the zirconia element. 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 three-way
catalytic converter is used. For the most efficient use of the three-way
catalytic converter, the air fuel ratio must be precisely controlled so
that it is always close to the stoichiometric air fuel ratio.
HINT:
- When any of these DTCs are stored, the ECM enters fail-safe mode. The
ECM turns off the air fuel ratio sensor (sensor 2) heater in fail-safe
mode. Fail-safe mode continues until the power switch is turned off.
- Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor (sensor 2).
- The ECM has a pulse width modulated control circuit to adjust the
current through the heater. The air fuel ratio sensor (sensor 2) 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 |
The
air fuel ratio sensor (sensor 2) heater current is more than the
specified value while the heater is operating (1 trip detection logic). |
- Short in air fuel ratio sensor (sensor 2) heater circuit
- Air fuel ratio sensor (sensor 2)
- ECM
| Comes on |
DTC stored | SAE Code: P0038 |
P003613 | A/F (O2) Heater Control Circuit Bank 1 Sensor 2 Circuit Open |
The
air fuel ratio sensor (sensor 2) heater current is less than the
specified value while the heater is operating (1 trip detection logic). |
- Open or short in air fuel ratio sensor (sensor 2) heater circuit
- Air fuel ratio sensor (sensor 2)
- EFI-MAIN NO. 2 relay
- ECM
| Comes on |
DTC stored | SAE Code: P0037 |
P102A9E | O2 Sensor Heater Performance Bank 1 Sensor 2 Stuck On |
The
air fuel ratio sensor (sensor 2) heater voltage is the specified value
or less while the heater is not operating (1 trip detection logic). |
- Short in air fuel ratio sensor (sensor 2) heater circuit
- Air fuel ratio sensor (sensor 2)
- ECM
| Comes on |
DTC stored | SAE Code: P102D | MONITOR DESCRIPTION
The
air fuel ratio sensor (sensor 2) detects oxygen levels in the exhaust
gas and transmits the information to the ECM. The inner surface of the
sensor element is exposed to the outside air. The outer surface of the
sensor element is exposed to the exhaust gas. The sensor element is made
of platinum-coated zirconia and includes an integrated heating element. The
zirconia element generates a small voltage when there is a large
difference in the oxygen concentrations between the exhaust gas and
outside air. The platinum coating amplifies this voltage generation. The
air fuel ratio sensor (sensor 2) is more efficient when heated. When
the exhaust gas temperature is low, the sensor cannot generate useful
current signals without supplementary heating. The ECM regulates the
supplementary heating using a duty-cycle approach to adjust the average
current in the sensor heater element. If the heater current is outside
the normal range, the signal transmitted by the air fuel ratio sensor
(sensor 2) becomes inaccurate. As a result, the ECM is unable to
regulate the air fuel ratio properly. Air Fuel Ratio Sensor (Sensor 2) Heater Range Check (P003612 and P003613):
- The ECM monitors the current applied to the air fuel ratio sensor (sensor 2) heater to check the heater for malfunctions.
If the heater current is outside the normal range, the
signal transmitted by the air fuel ratio sensor (sensor 2) becomes
inaccurate. When the current in the air fuel ratio sensor (sensor 2)
heater is outside the normal operating range, the ECM interprets this as
a malfunction in the sensor heater and stores a DTC.
Air Fuel Ratio Sensor (Sensor 2) Heater Performance (P102A9E):
- When the air fuel ratio sensor (sensor 2) heater terminal voltage is the
specified value or less while the heater is not operating, the ECM
determines that there is a malfunction in the sensor heater and stores
DTC.
MONITOR STRATEGY
Related DTCs | P0037: Air fuel ratio sensor (sensor 2) heater range check (low current)
P0038: Air fuel ratio sensor (sensor 2) heater range check (high current)
P102D: Air fuel ratio sensor (sensor 2) heater performance |
Required Sensors/Components (Main) | Air fuel ratio sensor (sensor 2) heater |
Required Sensors/Components (Related) | - |
Frequency of Operation | Continuous |
Duration | 10 seconds: P0037 and P0038 5 seconds: P102D |
MIL Operation | Immediate |
Sequence of Operation | None | TYPICAL ENABLING CONDITIONS P0037
All of the following conditions are met |
- | Auxiliary battery voltage |
10.5 V or higher | Time after heater on |
5 seconds or more | Air fuel ratio sensor (sensor 2) heater performance fail (P102D) |
Not detected | Output duty cycle |
30% or higher |
Heater high current cutout |
Off | P0038
Monitor runs whenever the following DTCs are not stored |
None | All of the following conditions are met |
- | Auxiliary battery voltage |
10.5 V or higher | Time after heater on |
5 seconds or more | CPU commanded duty cycle |
Higher than 5% | Output duty cycle |
Higher than 5% | P102D
Monitor runs whenever the following DTCs are not stored |
None | Both of the following conditions are met |
- | Auxiliary battery voltage |
10.5 V or higher | Output duty cycle |
Less than 95% | TYPICAL MALFUNCTION THRESHOLDS P0037
Heater on current | Less than 0.8 A | P0038
Either of the following conditions is met |
- | Heater on current detected by heater monitor IC |
More than 13 A | Heater on voltage detected by heater monitor IC |
[Auxiliary battery voltage x 0.1] V or higher | P102D
Heater off voltage detected by heater monitor IC |
[Auxiliary battery voltage x 0.33] V or less | CONFIRMATION DRIVING PATTERN
HINT:
- After repair has been completed, clear the DTC and then check that the
vehicle has returned to normal by performing the following All Readiness
check procedure.
Click here
- When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.
Click here
- Connect the Techstream to the DLC3.
- Turn the power switch on (IG).
- Turn the Techstream on.
- Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
- Turn the power switch off and wait for at least 30 seconds.
- Turn the power switch on (IG) [A].
- Turn the Techstream on.
- Put the engine in Inspection Mode (Maintenance Mode).
Click here
- 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 2500 rpm for 1 minute [C].
HINT:
During
charge control, the engine speed is set at idle. Therefore, the engine
speed does not increase when depressing the accelerator pedal. In this
case, perform steps [C] and [D] after charge control has completed.
- Idle the engine for 5 minutes or more [D].
- Enter the following menus: Powertrain / Engine / Trouble Codes [E].
- Read the pending DTCs.
HINT:
- 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, P003613 or P102A9E.
- Check the DTC judgment result.
Techstream 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
|
HINT:
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
HINT:
- Refer to "Data List / Active Test" [A/F Sensor Heater Duty B1S2].
Click here
- Sensor 1 refers to the sensor closest to the engine assembly.
- Sensor 2 refers to the sensor farthest away from the engine assembly.
- Change the fuel injection volume using the Control the Injection Volume
for A/F Sensor function provided in the Active Test and monitor the air
fuel ratio sensor (sensor 2) output current (Click here
). If the sensor output current does not change (almost no reaction)
while performing the Active Test, the sensor may be malfunctioning.
- Read Freeze Frame Data using the Techstream. 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
1. | INSPECT AIR FUEL RATIO SENSOR (SENSOR 2) (HEATER RESISTANCE) |
(a) Inspect the air fuel ratio sensor (sensor 2). Click here
HINT: Perform "Inspection After Repair" after replacing the air fuel ratio sensor (sensor 2).
Click here
NG |
| REPLACE AIR FUEL RATIO SENSOR (SENSOR 2) |
OK |
| |
2. |
CHECK TERMINAL VOLTAGE (POWER SOURCE OF AIR FUEL RATIO SENSOR (SENSOR 2)) |
*a | Front view of wire harness connector
(to Air Fuel Ratio Sensor (Sensor 2)) |
(a) Disconnect the air fuel ratio sensor (sensor 2) connector. (b) Turn the power switch on (IG).
(c) Measure the voltage according to the value(s) in the table below. Standard Voltage:
Tester Connection | Condition |
Specified Condition |
C49-2 (+B) - Body ground |
Power switch on (IG) |
11 to 14 V |
NG |
| GO TO STEP 6 |
OK |
| |
3. |
CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR (SENSOR 2) - ECM) |
(a) Disconnect the air fuel ratio sensor (sensor 2) connector. (b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection | Condition |
Specified Condition |
C49-1 (HA1B) - C55-8 (HA1B) |
Always | Below 1 Ω |
C49-1 (HA1B) or C55-8 (HA1B) - Body ground and other terminals |
Always | 10 kΩ or higher |
NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
| |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG). (c) Turn the Techstream on. (d) Clear the DTCs. Powertrain > Engine > Clear DTCs
(e) Turn the power switch off and wait for at least 30 seconds.
NEXT |
| |
5. |
CHECK WHETHER DTC OUTPUT RECURS (DTC P003612, P003613 AND/OR P102A9E) |
(a) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
(b) Enter the following menus: Powertrain / Engine / Trouble Codes. (c) Read the DTCs. Powertrain > Engine > Trouble Codes
Result | Proceed to |
DTCs are not output | A |
DTC P003612, P003613 and/or P102A9E is output |
B |
A |
| CHECK FOR INTERMITTENT PROBLEMS |
B |
| REPLACE ECM |
6. |
INSPECT EFI-MAIN NO. 2 RELAY | (a) Inspect the EFI-MAIN NO. 2 relay.
Click here
NG |
| REPLACE EFI-MAIN NO. 2 RELAY |
OK |
| |
7. |
CHECK TERMINAL VOLTAGE (POWER SOURCE OF EFI-MAIN NO. 2 RELAY) |
*1 | No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly |
*2 | EFI-MAIN NO. 2 Relay |
(a) Remove the EFI-MAIN NO. 2 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
(b) Measure the voltage according to the value(s) in the table below. Standard Voltage:
Tester Connection | Condition |
Specified Condition |
3 (EFI-MAIN NO. 2 relay) - Body ground |
Always | 11 to 14 V |
NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR (AUXILIARY BATTERY - EFI-MAIN NO. 2 RELAY) |
OK |
| |
8. |
CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY - BODY GROUND) |
(a) Remove the EFI-MAIN NO. 2 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection | Condition |
Specified Condition |
1 (EFI-MAIN NO. 2 relay) - Body ground |
Always | Below 1 Ω |
NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
| |
9. |
CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY - AIR FUEL RATIO SENSOR (SENSOR 2)) |
(a) Remove the EFI-MAIN NO. 2 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
(b) Disconnect the air fuel ratio sensor (sensor 2) connector. (c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection | Condition |
Specified Condition |
5 (EFI-MAIN NO. 2 relay) - C49-2 (+B) |
Always | Below 1 Ω |
5 (EFI-MAIN NO. 2 relay) or C49-2 (+B) - Body ground and other terminals |
Always | 10 kΩ or higher |
OK |
| REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI-MAIN NO. 1 RELAY - EFI-MAIN NO. 2 RELAY) |
NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR | |