Page 209 of 656
6-1-48 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0100 (DTC No.33, 34) Mass Air Flow Circuit Malfunction
WIRING DIAGRAM
DTC DETECTING CONDITION AND TROUBLE AREA
1. Main fuse
2. Main relay
3. ECM/PCM
4. Mass air flow sensor
DTC DETECTING CONDITION TROUBLE AREA
Any one of the following conditions are detected for 5
sec. continuously.
• Engine running and more than 3 sec. after ignition
switch ON and less than 0.64 mA MAF sensor out-
put current continues for 100 msec.
• Engine running and more than 3 sec. after ignition
switch ON and more than 4.90 mA MAF sensor out-
put current continues for 100 msec.• MAF sensor circuit
• MAF sensor
• ECM (PCM)
Page 222 of 656

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-61
DTC P0135 HO2S-1 (Bank 1) Heater Circuit Malfunction
WIRING DIAGRAM
Refer to DTC P0130.
DTC DETECTING CONDITION AND TROUBLE AREA
DTC CONFIRMATION PROCEDURE
1) Connect scan tool with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and run
engine at idle speed for 5 min.
3) Check pending DTC by using scan tool.
TROUBLESHOOTING
DTC DETECTING CONDITION TROUBLE AREA
Following condition is detected when HO2S heater is
electrically live (2 driving cycle detection logic).
• Current of HO2S heater is 5.3 A or more or less than
0.09 A, or
• Voltage of HO2S heater is 14.0 V or higher or lower
than 11.7 V.HO2S-1 heater circuit
HO2S-1 heater
ECM (PCM)
HO2S heater relay
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE
DIAG. FLOW TABLE” in
this section.
2 HO2S-1 heater check :
1) Disconnect HO2S-1 coupler with ignition
switch OFF.
2) Check resistance between “3” and “4” termi-
nal of HO2S-1 coupler.
HO2S-1 heater resistance :
5.0 – 6.4
Ω
ΩΩ Ω (at 20°C (68°F))
Is it within above specification?Go to Step 3. Replace HO2S-1.
3 HO2S heater power supply check :
1) With ignition switch ON leaving engine OFF,
check voltage between E139-3 and ground,
E139-1 and ground. (See Fig.)
Is each voltage 10 – 14 V?Go to Step 4. “HO2S”, and/or “IG
METER” fuse blown.
If OK, faulty “BLK/WHT”
wire or “BLU/WHT” wire.
Page 227 of 656

6-1-66 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
TROUBLESHOOTING
Fig. for STEP 2, 3Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE” in this
section.
2 HO2S-2 heater check :
1) Disconnect HO2S-2 coupler with ignition
switch OFF.
2) Check resistance between “3” and “4” termi-
nal of HO2S-2 connector.
HO2S -2 heater resistance :
11.7 – 14.3
Ω
ΩΩ Ω (at 20°C (68°F))
Is it within above specificationGo to Step 3. Replace HO2S-2.
3 HO2S heater power supply check :
1) With ignition switch ON leaving engine OFF,
check voltage between E139-3 and ground,
E139-1 and ground. (See Fig.)
Is each voltage 10 – 14 V?Go to Step 4. Fuse “HO2S” and/or “IG
METER” blown.
If OK, faulty “BLK/WHT”
wire or “BLU/WHT” wire.
4 HO2S heater control circuit check :
1) With ignition switch OFF, install HO2S
heater relay.
2) With ignition switch ON leaving engine OFF,
check voltage between C51-2-16 and
ground.
Is the voltage 10 – 14 V?Substitute a known-good
ECM (PCM) and recheck.Faulty HO2S heater relay
or “BLK” wire open, “BLU”
wire open or shorted to
ground circuit, “WHT/
BLK” wire open or shorted
to ground circuit.
If OK, substitute a known-
good ECM (PCM) and
recheck.
a. HO2S heater relay
Page 231 of 656

6-1-70 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0155 HO2S-1 (Bank 2) Heater Circuit Malfunction
WIRING DIAGRAM
Refer to DTC P0150.
DTC DETECTING CONDITION AND TROUBLE AREA
DTC CONFIRMATION PROCEDURE
1) Connect scan tool with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and run
engine at idle speed for 5 min.
3) Check pending DTC by using scan tool.
TROUBLESHOOTING
DTC DETECTING CONDITION TROUBLE AREA
Following condition is detected when HO2S heater is
electrically live (2 driving cycle detection logic).
• Current of HO2S heater is 5.3 A or more or less than
0.09 A, or
• Voltage of HO2S heater is 14.0 V or higher or lower
than 11.7 V.HO2S-1 heater circuit
HO2S-1 heater
ECM (PCM)
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE
DIAG. FLOW TABLE” in
this section.
2 HO2S-1 heater check :
1) Disconnect HO2S-1 coupler with ignition
switch OFF.
2) Check resistance between “3” and “4” termi-
nal of HO2S-1 coupler.
HO2S-1 heater resistance :
5.0 – 6.4
Ω
ΩΩ Ω (at 20°C (68°F))
Is it within above specification?Go to Step 3. Replace HO2S-1.
3 HO2S heater power supply check :
1) With ignition switch ON leaving engine OFF,
check voltage between E139-3 and ground,
E139-1 and ground. (See Fig.)
Is each voltage 10 – 14 V?Go to Step 4. “HO2S”, and/or “IG
METER” fuse blown.
If OK, faulty “BLK/WHT”
wire or “BLU/WHT” wire.
Page 236 of 656

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-75
TROUBLESHOOTING
Fig. for STEP 2, 3Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE” in this
section.
2 HO2S-2 heater check :
1) Disconnect HO2S-2 coupler with ignition
switch OFF.
2) Check resistance between “3” and “4” termi-
nal of HO2S-2 connector.
HO2S -2 heater resistance :
11.7 – 14.3
Ω
ΩΩ Ω (at 20°C (68°F))
Is it within above specificationGo to Step 3. Replace HO2S-2.
3 HO2S heater power supply check :
1) With ignition switch ON leaving engine OFF,
check voltage between E139-3 and ground,
E139-1 and ground. (See Fig.)
Is each voltage 10 – 14 V?Go to Step 4. Fuse “HO2S” and/or “IG
METER” blown.
If OK, faulty “BLK/WHT”
wire or “BLU/WHT” wire.
4 HO2S heater control circuit check :
1) With ignition switch OFF, install HO2S
heater relay.
2) With ignition switch ON leaving engine OFF,
check voltage between C51-2-17 and
ground.
Is the voltage 10 – 14 V?Substitute a known-good
ECM (PCM) and recheck.Faulty HO2S heater relay
or “BLK” wire open, “BLU”
wire open or shorted to
ground circuit, “PNK/
WHT” wire open or
shorted to ground circuit.
If OK, substitute a known-
good ECM (PCM) and
recheck.
a. HO2S heater relay
Page 250 of 656
ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-89
DTC P0400 Exhaust Gas Recirculation Flow Malfunction
SYSTEM/WIRING DIAGRAM
1. EGR valve 5. ECM (PC)
2. Intake manifold 6. MAP sensor
3. Exhaust gas 7. Main fuse
4. Sensed information 8. Main relay
Page 253 of 656

6-1-92 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0403 (DTC No.51) Exhaust Gas Recirculation Circuit Malfunction
WIRING DIAGRAM
DTC DETECTING CONDITION AND TROUBLE AREA
DTC CONFIRMATION PROCEDURE
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool.
3) Start engine and run it for 10 sec.
4) Check DTC by using scan tool.
1. Main fuse 4. ECM (PCM)
2. Main relay
3. EGR valve
DTC DETECTING CONDITION TROUBLE AREA
High voltage is detected at EGR valve stepping motor
electrical circuit for specified time continuously.
(Circuit open or short).EGR valve (stepping motor) or its circuit ECM
(PCM)
NOTE:
Check to make sure that following condition is satisfied when using this “DTC CONFIRMATION PRO-
CEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Page 259 of 656

6-1-98 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0443 Evap Control System Purge Control Valve Circuit Malfunction
SYSTEM/WIRING DIAGRAM
DTC DETECTING CONDITION AND TROUBLE AREA
DTC CONFIRMATION PROCEDURE
1. Main fuse 3. EVAP canister purge valve
2. Main relay 4. ECM (PCM)
DTC DETECTING CONDITION TROUBLE AREA
Monitor signal of EVAP canister purge valve is different
from command signal. (Circuit open or short)
(2 driving cycle detection logic)• EVAP canister purge valve and its circuit
•ECM (PCM)
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.
NOTE:
Check to make sure that following condition is satisfied when using the “DTC Confirmation Proce-
dure.”
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)