DESCRIPTION
Refer to DTC P2195 (See page ).
HINT:
DTC No. |
DTC Detection Condition |
Trouble Area |
---|---|---|
P0031 |
Air fuel ratio sensor heater current is less than 0.8 A, even when the air fuel ratio sensor heater duty cycle is 30% or higher (1 trip detection logic). |
|
P0032 |
Air fuel ratio sensor heater current reaches the high limit (1 trip detection logic). |
|
P101D |
The heater current is higher than the specified value while the heater is not operating (1 trip detection logic). |
ECM |
MONITOR DESCRIPTION
The ECM uses information from the air fuel ratio sensor to regulate the air fuel ratio and keep it close to the stoichiometric level. This maximizes the ability of the three-way catalytic converter to purify the exhaust gases.
The air fuel ratio sensor 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 is more efficient when heated. When the exhaust gas temperature is low, the sensor cannot generate useful voltage 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 becomes inaccurate. As a result, the ECM is unable to regulate the air fuel ratio properly.
When the current in the air fuel ratio 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
Related DTCs |
P0031: Air Fuel Ratio Sensor Heater range check (Low Current) P0032: Air Fuel Ratio Sensor Heater range check (High Current) P101D: Air Fuel Ratio Sensor Heater Performance |
Required Sensors/Components (Main) |
Air fuel ratio sensor heater |
Required Sensors/Components (Related) |
- |
Frequency of Operation |
Continuous |
Duration |
10 seconds: P0031 10.24 seconds: P0032 1 second: P101D |
MIL Operation |
Immediate |
Sequence of Operation |
None |
TYPICAL ENABLING CONDITIONS
P0031
Monitor runs whenever the following DTCs are not stored |
None |
All of the following conditions are met |
- |
Battery voltage |
10.5 V or more |
Time after heater on |
5 seconds or more |
Active heater off control |
Not operating |
Active heater on control |
Not operating |
Air fuel ratio sensor heater performance fail (P101D) |
Not detected |
Output duty cycle |
30% or more |
Monitor runs whenever the following DTCs are not stored |
None |
All of the following conditions are met |
- |
Battery voltage |
10.5 V or more |
Time after heater on |
5 seconds or more |
Output duty cycle |
More than 0% |
Active heater off control |
Not operating |
Active heater on control |
Not operating |
Monitor runs whenever the following DTCs are not stored |
None |
All of the following conditions are met |
10 seconds or more |
Battery voltage |
10.5 V or more |
Time after heater on |
5 seconds or more |
Output duty cycle |
Less than 60% |
Active heater off control |
Not operating |
Active heater on control |
Not operating |
Air fuel ratio sensor heater low current fail (P0031) |
Not detected |
TYPICAL MALFUNCTION THRESHOLDS
P0031
Heater on current |
Less than 0.8 A |
Both of the following conditions are met |
- |
Command to heater output |
ON |
Heater current detected by heater monitor IC |
14 A or more |
Both of the following conditions are met |
- |
Heater off current |
More than 11 A |
Heater current detected by heater monitor IC |
14 A or more |
COMPONENT OPERATING RANGE
P0031
Heater on current |
0.8 A or more |
Both of the following conditions are met |
- |
Command to heater output |
ON |
Heater current detected by heater monitor IC |
Less than 14 A |
Heater off current |
11 A or less |
CONFIRMATION DRIVING PATTERN
HINT:
Techstream Display |
Description |
---|---|
NORMAL |
|
ABNORMAL |
|
INCOMPLETE |
|
N/A |
|
HINT:
HINT:
WIRING DIAGRAM
Refer to DTC P2195 (See page ).
CAUTION / NOTICE / HINT
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT:
PROCEDURE
1. |
INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE) |
(a) Inspect the air fuel ratio sensor (See page
).
HINT:
Perform "Inspection After Repair" after replacing the air fuel ratio sensor (See
page ).
NG | ![]() |
REPLACE AIR FUEL RATIO SENSOR |
|
2. |
CHECK TERMINAL VOLTAGE (POWER SOURCE OF AIR FUEL RATIO SENSOR) |
(a) Disconnect the air fuel ratio sensor connector. |
|
(b) Turn the ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection |
Switch Condition |
Specified Condition |
---|---|---|
B7-2 (+B) - Body ground |
Ignition switch ON |
11 to 14 V |
*a |
Front view of wire harness connector (to Air Fuel Ratio Sensor) |
NG | ![]() |
GO TO STEP 5 |
|
3. |
CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM) |
(a) Disconnect the air fuel ratio sensor connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Tester Connection |
Condition |
Specified Condition |
---|---|---|
B7-1 (HA1A) - B58-18 (HA1A) |
Always |
Below 1 Ω |
Standard Resistance (Check for Short):
Tester Connection |
Condition |
Specified Condition |
---|---|---|
B7-1 (HA1A) or B58-18 (HA1A) - Body ground |
Always |
10 kΩ or higher |
NG | ![]() |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
4. |
CHECK WHETHER DTC OUTPUT RECURS (DTC P0031, P0032 OR P101D) |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Clear the DTCs (See page ).
(e) Turn the ignition switch off and wait for at least 30 seconds.
(f) Allow the vehicle to drive in accordance with the driving pattern described in the Confirmation Driving Pattern.
(g) Enter the following menus: Powertrain / Engine / Trouble Codes.
(h) Read the DTCs.
Result |
Proceed to |
---|---|
DTC is not output |
A |
DTC P0031, P0032 or P101D is output |
B |
A | ![]() |
CHECK FOR INTERMITTENT PROBLEMS |
B | ![]() |
REPLACE ECM |
5. |
INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (EFI MAIN NO. 2 RELAY) |
(a) Inspect the EFI MAIN No. 2 relay (See page
).
NG | ![]() |
REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY |
|
6. |
CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - EFI MAIN NO. 2 RELAY) |
(a) Disconnect the air fuel ratio sensor connector.
(b) Remove the engine room junction block assembly from the engine room relay block.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Tester Connection |
Condition |
Specified Condition |
---|---|---|
B7-2 (+B) - 1F-9 |
Always |
Below 1 Ω |
Standard Resistance (Check for Short):
Tester Connection |
Condition |
Specified Condition |
---|---|---|
B7-2 (+B) or 1F-9 - Body ground |
Always |
10 kΩ or higher |
OK | ![]() |
REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - EFI MAIN NO. 2 RELAY) |
NG | ![]() |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
Installation
INSTALLATION
PROCEDURE
1. INSTALL SEPARATE TYPE FRONT SEAT CUSHION COVER
(a) Using a tacker, install the separate type front seat cushion heater
to the end of the separate type front seat cushion cover with 25 new tack
pins.
NOTICE:
...
Sleep Operation Failure of Occupant Classification ECU (B1796)
DESCRIPTION
In sleep mode, the occupant classification ECU reads the condition of each sensor
while the ignition switch is off.
In this mode, if occupant classification ECU detects an internal malfunction,
DTC B1796 is output.
DTC No.
...
Front Passenger Side Door Entry Unlock Function does not Operate
DESCRIPTION
If the front passenger door entry lock function operates normally, but its entry
unlock function does not, this means that the request code from the front passenger
door is being output normally. In this case, a malfunction in the touch sensor ...