DTC P0031 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 1) DTC P0032 Oxygen Sensor Heater Control Circuit High (Bank 1 Sensor 1)

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1 DI0 DIGNOSTICS ENGINE (UZFE) CICUIT INSPECTION DICMP0 DTC P00 Oxygen Sensor Heater Control Circuit Low (ank Sensor ) DTC P00 Oxygen Sensor Heater Control Circuit High (ank Sensor ) DTC P007 Oxygen Sensor Heater Control Circuit Low (ank Sensor ) DTC P008 Oxygen Sensor Heater Control Circuit High (ank Sensor ) DTC P005 Oxygen Sensor Heater Control Circuit Low (ank Sensor ) DTC P005 Oxygen Sensor Heater Control Circuit High (ank Sensor ) DTC P0057 Oxygen Sensor Heater Control Circuit Low (ank Sensor ) DTC P0058 Oxygen Sensor Heater Control Circuit High (ank Sensor ) 606

2 DIGNOSTICS ENGINE (UZFE) DI CICUIT DESCIPTION To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a threeway catalytic converter is used, but for the most efficient use of the threeway catalytic converter, the airfuel ratio must be precisely controlled so that it is always close to the stoichiometric airfuel ratio. The heated oxygen sensor has the characteristic which its output voltage changes suddenly in the vicinity of the stoichiometric airfuel ratio. This characteristic is used to detect the oxygen concentration in the exhaust gas and provide the ECM with feedback to control the airfuel ratio. When the airfuel ratio becomes LEN, the oxygen concentration in the exhaust increases and the heated oxygen sensor informs the ECM of the LEN condition (low voltage, i.e. less than 0.5 V). When the airfuel ratio is ICHE than the stoichiometric airfuel ratio, the oxygen concentration in the exhaust gas is reduced and the heated oxygen sensor informs the ECM of the ICH condition (high voltage, i.e. more than 0.5 V). The ECM judges by the voltage output from the heated oxygen sensor whether the airfuel ratio is ICH or LEN and controls the injection time accordingly. However, if malfunction of the heated oxygen sensor causes output of abnormal voltage, this disables the ECM for performing an accurate airfuel ratio control. The heated oxygen sensors include a heater which heats the zirconia element. The heater is controlled by the ECM. When the intake air volume is low (the temperature of the exhaust gas is low) current flows to the heater to heat the sensor for accurate oxygen concentration detection. tmosphere Housing Ideal irfuel Mixture Platinum Electrode Solid Electrolyte (Zirconia Element) Platinum Electrode Heater Coating (Ceramic) Output Voltage Cover icher ir Fuel atio Leaner P00 FI70 Exhaust Gas HINT: The ECM provides a pulse width modulated control circuit to adjust current through the heater. The heated oxygen sensor heater circuit uses a relay on the + side of the circuit. eference (ank Sensor System Drawing) : From attery EFI Fuse No. EFI elay + Heater HT EFI Fuse No. Sensor E OX HT OX E ECM Duty Control Ground MEL

3 DI DIGNOSTICS ENGINE (UZFE) DTC No. DTC Detecting Condition Trouble rea P00 P007 P005 P0057 P00 P008 P005 P0058 Heater current is 0.5 or less when the heater operates with more than 0.5 V positive battery voltage When heater operates, heater current exceeds.0 HINT: ank refers to bank the includes cylinder No.. ank refers to bank that does not includes cylinder No.. Sensor refers to the sensor closer to the engine assembly. Sensor refers to the sensor farther away from the engine assembly. Open in heater circuit of heated oxygen sensor Heated oxygen sensor heater EFI relay ECM Short in heater circuit of heated oxygen sensor Heated oxygen sensor heater EFI relay ECM MONITO DESCIPTION The sensing portion of the heated oxygen sensor has a zirconia element which is used to detect oxygen concentration in the exhaust. If the zirconia element is at the proper temperature and difference of the oxygen concentration between the inside and outside surface of sensor is large, the zirconia element will generate voltage signals. In order to increase the oxygen concentration detecting capacity in the zirconia element, the ECM supplements the heat from the exhaust with heat from a heating element inside the sensor. When current in the sensor is out of the standard operating range, the ECM interprets this as a fault in the heated oxygen sensor and sets a DTC. Example: The ECM will set a high current DTC if the current in the sensor is more than.0 when the heater is OFF. Similarly, the ECM will set a low current DTC if the current is less than 0.5 when the heater is ON. 608

4 DIGNOSTICS ENGINE (UZFE) DI MONITO STTEGY elated DTCs equired sensors/components Frequency of operation Duration MIL operation Sequence of operation P00 P00 P007 P008 P005 P005 P0057 P0058 Main sensors/components elated sensors/components Continuous 0. sec. P00, P007, P005, P0057: driving cycle P00, P008, P005, P0058: Immediate None Heated oxygen sensor heater current bank sensor (Low current) Heated oxygen sensor heater current bank sensor (High current) Heated oxygen sensor heater current bank sensor (Low current) Heated oxygen sensor heater current bank sensor (High current) Heated oxygen sensor heater current bank sensor (Low current) Heated oxygen sensor heater current bank sensor (High current) Heated oxygen sensor heater current bank sensor (Low current) Heated oxygen sensor heater current bank sensor (High current) Heated oxygen sensor Vehicle speed sensor TYPICL ENLING CONDITIONS Item Minimum Specification Maximum The monitor will run whenever the following DTCs are not present See List of disable a monitor (on page DI85) P00, P007, P005, P0057 (Low current): Either of the following conditions is met: or. Following conditions are met:,,, and 5. Time after engine start 50 sec. 500 sec.. attery voltage 0.5 V. Vehicle speed 90 km/h (56 mph). Misfire Not detected 5. Pass/Fail detection in this driving cycle Not detected. Following conditions are met:,,, and 5. Time after engine start 500 sec.. attery voltage 0.5 V. Vehicle speed 0 km/h (5 mph). Misfire Not detected 5. Pass/Fail detection in this driving cycle Not detected P00, P008, P005, P0058 (High current): Intrusive heating is OFF 609

5 DI DIGNOSTICS ENGINE (UZFE) TYPICL MLFUNCTION THESHOLDS Detection Criteria P00, P007, P005, P0057 (Low current): Heated oxygen sensor heater current P00, P008, P005, P0058 (High current): Heated oxygen sensor heater current Threshold Less than 0.5 (at 0. sec. after heater ON ) More than.0 (while intrusive heating is OFF) COMPONENT OPETING NGE Parameter Heated oxygen sensor heater current under the following conditions: (a) Engine has been warmed up (b) Engine is idling (c) attery voltage is to V Standard Value 0. to.0 MONITO ESULT The detailed information is described in CHECKING MONITO STTUS (see page DI85). TID (Test Identification) is assigned to each emissionrelated component. TLT (Test Limit Type): If TLT is 0, the component is malfunctioning when the test value is higher than the test limit. If TLT is, the component is malfunctioning when the test value is lower than the test limit. CID (Component Identification) is assigned to each test value. Unit Conversion is used to calculate the test value indicated on generic OD scan tools. TID $0: HOS Heater TLT CID Unit Conversion Description of Test Value Description of Test Limit $0 Multiply by () Maximum HOS heater current (bank sensor ) Malfunction criterion $0 Multiply by () Maximum HOS heater current (bank sensor ) Malfunction criterion $0 Multiply by () Maximum HOS heater current (bank sensor ) Malfunction criterion $0 Multiply by () Maximum HOS heater current (bank sensor ) Malfunction criterion 60

6 DIGNOSTICS ENGINE (UZFE) DI5 WIING DIGM CCESS C, STNDD C: 7 J6 J7 J8 IE H (ank Sensor ) + HTL Y 5 ECM HT EFI NO. Engine oom / E OXL H6 (ank Sensor ) + HT Y 9 5 OX HT J 5 WL WL EFI NO. Engine oom / EFI elay Engine oom / Y 9 J6 J8 J5 6 J7 H (ank Sensor ) + HTL GY H5 (ank Sensor ) + HT YG E Y E E OX OX OX W W 8 E 8 E7 OX MEL HT OX HT OX E 7 E5 E0 From attery E E

7 DI6 DIGNOSTICS ENGINE (UZFE) DOULE C: F D J I Engine oom J/ EFI elay EFI NO. G 5 G 9 J7 EFI NO. 6 J8 G 6 H IE F Fusible Link lock H (ank Sensor ) + HTL GY E OXL H5 (ank Sensor ) + HT YG E OX W H6 (ank Sensor ) + HT Y E OX W H (ank Sensor ) + HTL Y E OXL W (*) (*) 8 E ECM MEL HT OX HT OX HT OX HT OX E J5 attery EC 8 E7 E5 E E 8 6

8 DIGNOSTICS ENGINE (UZFE) DI7 INSPECTION POCEDUE HINT: ead freeze frame data using handheld tester or OD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the airfuel ratio was lean or rich, etc. at the time of the malfunction. Check resistance of heated oxygen sensor heater. + H H5 OX E OX ank Sensor, ank Sensor + HT HTL HT HTL PEPTION: Disconnect the H, H, H5 or H6 heated oxygen sensor connector. CHECK: Measure resistance between terminals of the heated oxygen sensor. OK: Tester Connection HTL (H) + (H) HTL (H) + (H) HT (H5) + (H5) HT (H6) + (H6) Specified Condition to 6 Ω (0 C) to 6 Ω (0 C) to 6 Ω (0 C) to 6 Ω (0 C) H H6 E OX OXL ank Sensor, ank Sensor 0870 NG eplace heated oxygen sensor. OK 6

9 DI8 DIGNOSTICS ENGINE (UZFE) Check EFI relay. EFI elay PEPTION: emove the EFI relay from the engine room J/. CHECK: Inspect the EFI relay. OK: Terminal No. Condition Specified Condition Constant Ω Constant More than 0 kω pply + between terminals and Less than Ω NG eplace EFI relay. OK Check voltage between terminals HT, HT, HT, HT of ECM connectors and body ground. ECM HT (+) HT (+) 95 HT (+) HT (+) 960 PEPTION: Turn the ignition switch ON. CHECK: Measure the voltage of the ECM connector terminals as shown in the chart below. HINT: Connect terminal HT to the bank sensor. Connect terminal HT to the bank sensor. Connect terminal HT to the bank sensor. Connect terminal HT to the bank sensor. OK: Symbols (Terminal No.) Specified Condition HT () ody ground HT (5) ody ground HT () ody ground 9 V HT (5) ody ground OK eplace ECM (See page SF5). NG Check and repair harness or connector between EFI relay and heated oxygen sensor, and heated oxygen sensor and ECM (See page IN7). 6