6-68 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P0133 HEATED OXYGEN SENSOR (HO2S) CIRCUIT SLOW RESPONSE
(SENSOR-1)
WIRING DIAGRAM / CIRCUIT DESCRIPTION
Refer to DTC P0130 section.
Fig. 1
DTC CONFIRMATION PROCEDURE
Refer to DTC P0130 section.
INSPECTION
DTC DETECTING CONDITION POSSIBLE CAUSE
When running at specified idle speed after engine warmed up and
running at specified vehicle speed, response time (time to change
from lean to rich or from rich to lean) of HO2S-1 output voltage is
about 1 sec. at minimum or average time of 1 cycle is 5 sec. at
minimum. See. Fig. 1
✱2 driving cycle detection logic, Monitoring once/1 driving.Heated oxygen sensor-1 malfunction
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE”.
2 Is there DTC(s) other than HO2S-1 (DTC
P0133)?Go to applicable DTC
Diag. Flow Table.Replace HO2S-1.
ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-69
DTC P0134 HEATED OXYGEN SENSOR (HO2S) CIRCUIT NO ACTIVITY
DETECTED (SENSOR-1)
WIRING DIAGRAM / CIRCUIT DESCRIPTION
Refer to DTC P0130 section.
DTC CONFIRMATION PROCEDURE
Refer to DTC P0131 section.
INSPECTION
Fig. 1 for Step 3DTC DETECTING CONDITION POSSIBLE CAUSE
Engine warmed up.
While running under other than high load and high engine speed
conditions or at specified idle speed (engine is in closed loop con-
dition), HO2S-1 output voltage is high or low continuously.
✱2 driving cycle detection logic, Continuous monitoring.“WHT” or “ORN” circuit open or short
Heated oxygen sensor malfunction
Fuel system malfunction
Exhaust gas leakage
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE”.
2 Is there DTC(s) other than Fuel system
(DTC P0171/P0172) and HO2S-1 (DTC
P0134)?Go to applicable DTC
Diag. Flow Table.Go to Step 3.
3 Check HO2S-1 and Its Circuit.
1) Connect scan tool to DLC with ignition
switch OFF.
2) Warm up engine to normal operating tem-
perature and keep it at 2000 r/min. for 60
sec.
3) Repeat racing engine (Repeat depressing
accelerator pedal 5 to 6 times continuously
and take foot off from pedal to enrich and
enlean A/F mixture). See Fig. 1.
Does HO2S-1 output voltage deflect between
0.3V and over 0.6V repeatedly?Go to DTC P0171 and
P0172 Diag. Flow Table
(Fuel System Check).Check “WHT” and “ORN”
wires for open and short,
and connections for poor
connection. If wires and
connections are OK,
replace HO2S-1.
ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-77
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Check vehicle and environmental condition for :
–Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
–Ambient temp. : –10°C, 14°F or higher
–Intake air temp. : 70°C, 158°F or lower
4) Start engine and drive vehicle under usual driving condition (described in DTC confirmation procedure of
DTC P0136) for 5 min. or longer and until engine is warmed up to normal operating temperature.
5) Keep vehicle speed at 30 – 40 mph, 50 – 60 km/h in 5th gear or “D” range for 5 min. or more.
6) Stop vehicle (do not turn ignition switch OFF).
7) Check pending DTC in “ON BOARD TEST” or “PENDING DTC” mode and DTC in “DTC” mode.
INSPECTION
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic acci-
dent and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester, on a level road.
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE”.
2 Is there DTC(s) other than fuel system (DTC
P0171/P0172)?Go to applicable DTC
Diag. Flow Table.Go to Step 3.
3 Check HO2S-1 Output Voltage.
1) Connect scan tool to DLC with ignition
switch OFF.
2) Warm up engine to normal operating tem-
perature and keep it at 2000 r/min. for 60
sec.
3) Repeat racing engine (Repeat depressing
accelerator pedal 5 to 6 times continuously
and take foot off from pedal to enrich and
enlean A/F mixture). See Fig. 1.
Does HO2S-1 output voltage deflect between
below 0.3 V and over 0.6 V repeatedly?Go to Step 4. Go to DTC P0130 Diag.
Flow Table (HO2S-1 cir-
cuit check).
4 Check Fuel Pressure (Refer to section 6E1 for
details).
1) Release fuel pressure from fuel feed line.
2) Install fuel pressure gauge.
3) Check fuel pressure. See Fig. 2. With fuel
pump operating and engine at stop :
270 – 310 kPa, 2.7 – 3.1 kg/cm
2, 38.4 –
44.0 psi.
At specified idle speed :
270 – 310 kPa, 2.7 – 3.1 kg/cm
2, 38.4 –
44.0 psi.
Is measured value as specified?Go to Step 5. Go to Diag. Flow Table B-
3 Fuel Pressure Check.
