P101D
2AZ-FXE ENGINE CONTROL: SFI SYSTEM: P0031, P0032, P101D: Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)
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DESCRIPTION
Refer to DTC P2195 P2195.
HINT
- When any of these DTCs is set, the hybrid vehicle control ECU enters fail-safe mode. The hybrid vehicle control ECU turns off the air fuel ratio sensor heater in fail-safe mode. Fail-safe mode continues until the power switch is turned off.
- Although the DTC titles say the oxygen sensor, these DTCs relate to the air fuel ratio sensor.
- Bank 1 sensor 1 refers to the sensor mounted in front of the Three-way catalytic converter and located near the engine assembly.
- The hybrid vehicle control ECU uses pulse width modulation to adjust the current through the heater. The air fuel ratio sensor heater circuit uses a relay on the +B side of the circuit.
HINT
- Bank 1 sensor 1 refers to the sensor closest to the engine assembly.
- Bank 1 sensor 2 refers to the sensor farthest away from the engine assembly.
MONITOR DESCRIPTION
The hybrid vehicle control ECU 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 hybrid vehicle control ECU. 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 hybrid vehicle control ECU 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 hybrid vehicle control ECU is unable to regulate air fuel ratio properly.
When the current in the air fuel ratio sensor heater is outside the normal operating range, the hybrid vehicle control ECU interprets this as a malfunction in the sensor heater and sets a DTC.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
P0031
P0032
P101D
TYPICAL MALFUNCTION THRESHOLDS
P0031
P0032
P101D
COMPONENT OPERATING RANGE
P0031
P0032
P101D
CONFIRMATION DRIVING PATTERN
1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG) and turn the Techstream on.
3. Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
4. Turn the power switch off and wait for at least 30 seconds.
5. Turn the power switch on (IG) and turn the Techstream on [A].
6. Put the engine in inspection mode Component Tests and General Diagnostics.
7. Start the engine and idle it for 5 minutes or more [B].
8. With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 2500 rpm for 1 minute [C].
9. Idle the engine for 5 minutes or more [D].
10. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
11. Read the DTC [E].
HINT
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.
12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
13. Input the DTC: P0031, P0032, or P101D.
14. Check the DTC judgment result.
15. If the judgment result shows INCOMPLETE or UNKNOWN, perform step [B] through [E] again.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT
Read freeze frame data using the Techstream. The hybrid vehicle control ECU 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 (HEATER RESISTANCE)
(a) Disconnect the air fuel ratio sensor connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
(c) Reconnect the air fuel ratio sensor connector.
NG -- REPLACE AIR FUEL RATIO SENSOR Removal
OK -- Continue to next step.
2. CHECK TERMINAL VOLTAGE (POWER SOURCE)
(a) Disconnect the air fuel ratio sensor connector.
(b) Turn the power switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Text in Illustration
(d) Reconnect the air fuel ratio sensor connector.
NG -- INSPECT INTEGRATION RELAY (EFI MAIN RELAY)
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - HYBRID VEHICLE CONTROL ECU)
(a) Disconnect the air fuel ratio sensor connector.
(b) Disconnect the hybrid vehicle control ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Standard Resistance (Check for Short):
(d) Reconnect the air fuel ratio sensor connector.
(e) Reconnect the hybrid vehicle control ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. CHECK WHETHER DTC OUTPUT RECURS (DTC P0031 OR P0032 OR P101D)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(e) Put the engine in inspection mode Component Tests and General Diagnostics.
(f) Start the engine.
(g) Allow the engine to idle for 5 minutes or more.
(h) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(i) Read the DTCs.
Result:
B -- REPLACE HYBRID VEHICLE CONTROL ECU Removal
A -- CHECK FOR INTERMITTENT PROBLEMS Check For Intermittent Problems
5. INSPECT INTEGRATION RELAY (EFI MAIN RELAY)
(a) Inspect the integration relay Inspection.
NG -- REPLACE INTEGRATION RELAY Removal
OK -- Continue to next step.
6. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - AIR FUEL RATIO SENSOR)
(a) Remove the integration relay from the engine room relay block.
(b) Disconnect the integration relay connector.
(c) Disconnect the air fuel ratio sensor connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Standard Resistance (Check for Short):
(e) Reconnect the air fuel ratio sensor connector.
(f) Reconnect the integration relay connector.
(g) Reinstall the integration relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - IGCT RELAY)
(a) Remove the integration relay from the engine room relay block.
(b) Disconnect the integration relay connector.
(c) Remove the IGCT relay from the engine room relay block.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Standard Resistance (Check for Short):
(e) Reconnect the integration relay connector.
(f) Reinstall the integration relay.
(g) Reinstall the IGCT relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - BODY GROUND)
(a) Remove the integration relay from the engine room relay block.
(b) Disconnect the integration relay connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
(d) Reconnect the integration relay connector.
(e) Reinstall the integration relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - EFI MAIN RELAY)