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) 
         
        
        
     
        
        Page 269 of 656
6-1-108 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0505 Idle Air Control System Malfunction
SYSTEM/WIRING DIAGRAM
DTC DETECTING CONDITION AND TROUBLE AREA
1. Throttle body 3. ECM (PCM) 5. FIA valve 7. Main relay
2. Idle air control valve 4. Sensed information 6. Main fuse
DTC DETECTING CONDITION TROUBLE AREA
•Engine idle speed is 100 r/min. or more lower than target idle 
speed for longer than 20 sec. continuously.
or
•Engine idle speed is 200 r/min or more higher than target 
idle speed for longer than 20 sec. continuously.
(2 driving cycle detection logic)•IAC valve or its circuit
•Abnormal air drawn in air intake system
•FIA (fast idle air) valve 
         
        
        
     
        
        Page 276 of 656

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-115
DTC P1510 Ecm Back-Up Power Supply Malfunction
WIRING DIAGRAM
CIRCUIT DESCRIPTION
Battery voltage is supplied to keep DTC memory, values that ECM has learned to control engine, etc. in ECM
even when ignition switch is turned OFF.
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 and run
engine at idle speed for 1min.
3) Check DTC by using scan tool.
TROUBLESHOOTING
1. Main fuse box 3. ECM (PCM)
2. To DLC
DTC DETECTING CONDITION TROUBLE AREA
Back-up circuit voltage lower than specification is detected 
while engine is running.•ECM (PCM) back-up 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)
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE DIAG. FLOW 
TABLE” in this section.
2 Battery voltage supply circuit check :
1) Remove ECM (PCM) cover.
2) While engine running, check voltage between E61-
2 and ground.
Is voltage 10 – 14 V?Poor E61-2 connection or 
intermittent trouble.
Check for intermittent referring 
to “INTERMITTENT AND 
POOR CONNECTION” in 
Section 0A.
If wire and connections are 
OK, substitute a known-good 
ECM (PCM) and recheck.“WHT” circuit open or short. 
         
        
        
     
        
        Page 277 of 656
6-1-116 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
Table B-1 Fuel Pump Circuit Inspection
WIRING DIAGRAM
INSPECTION
1. To ignition switch 4. Fuel pump relay
2. Main fuse 5. Fuel pump
3. Main relay 6. ECM (PCM)
CAUTION:
Check to make sure that connection is made between correct terminals. 
Wrong connection can cause damage to ECM, wire harness etc.
Step Action Yes No
1 Fuel pump operation check : 
1) Remove fuel filler cap.
2) Turn ON ignition switch.
Is fuel pump operation sound heard for 3 sec. 
after ignition switch ON?Fuel pump circuit is in 
good condition.Go to Step 2.
2 Fuel pump circuit check : 
1) With ignition switch OFF, remove fuel pump 
relay from connector.
2) Check for proper connection to relay at 
each terminal.
3) If OK, using service wire, connect terminals 
E07-7 and E07-8 of relay connector. (See 
Fig.)
Is fuel pump heard to operate at ignition switch 
ON?Go to Step 3.“BLU/BLK”, “PNK/BLK” or 
“BLK” circuit open or fuel 
pump malfunction. 
         
        
        
     
        
        Page 285 of 656

6-1-124 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
Table B-6 A/C Condenser Fan Motor Relay Control System Inspection (If 
Equipped)
WIRING DIAGRAM
INSPECTION
1. To ignition switch 3. A/C fuse 5. A/C condenser fan motor
2. Main fuse 4. A/C condenser fan motor relay 6. ECM (PCM)
WARNING:
Keep hands, tools, and clothing away from A/C condenser fan to help prevent personal injury. This
fan is electric and can come on whether or not the engine is running. The fan can start automatically
in response to the ECT sensor with the ignition switch in the “ON” position.
Step Action Yes No
1 1) Check DTC referring to “DTC CHECK” in this sec-
tion.
Is there any malfunction DTC?Go to applicable DTC 
Diag. Flow Table.Go to Step 2.
2 1) Check A/C condenser fan for operation. 
A/C condenser fan should be operated under follow-
ing condition A or B only.
A : When engine is running and A/C is operating.
B : When engine coolant temp. is 113°C (235°F) or 
more with ignition switch ON.
Is check result as specified?This system is in 
good condition.Go to Step 3.
3 1) Remove ECM (PCM) cover.
2) Check voltage between E61-22 terminal of ECM 
(PCM) connected coupler and ground. 
Other than conditions A and B in Step 2 : 
10 – 14 V
Under condition A or B in Step 2 : 
0 – 1 V
Is check result as specified?Fuse blown, “RED”, 
“RED/BLK” or “RED/
BLU” circuit open, 
malfunction of con-
denser fan motor or 
relay.“YEL/GRN” circuit 
open, “YEL/BLU” cir-
cuit open or short, or 
relay malfunction.
If above are OK, sub-
stitute a known-good 
ECM (PCM) and 
recheck. 
         
        
        
     
        
        Page 341 of 656

6E2-8 ENGINE AND EMISSION CONTROL SYSTEM (SEQUENTIAL MULTIPORT FUEL INJECTION FOR H27 ENGINE)
Electronic Control System
The electronic control system consists of 1) various sensors which detect the state of engine and driving condi-
tions, 2) ECM (PCM) which controls various devices according to the signals from the sensors and 3) various
controlled devices.
Functionally, it is divided into the following sub systems:
•Fuel injection control system
•Heated oxygen sensor heater control system (if equipped)
•Idle air control system
•Fuel pump control system
•Evaporative emission control system
•Ignition control system
•EGR system (if equipped)
Also, with A/T model, PCM controls A/T.
INFORMATION SENSORS CONTROLLED DEVICES OTHERS
1. IAT sensor a : A/C condenser fan motor relay (if equipped) A : Main fuse box
2. MAP sensor (if equipped) b : Ignition coil assemblies B : ECM (PCM)
3. Heated oxygen sensor (sensor 1) (if equipped) c :  EVAP canister purge valve C : Data link connector
4. ECT sensor d :  EGR valve (if equipped) D : Combination meter
5. TP sensor e : Idle air control valve E : Fuse box
6. MAF sensor f : Injectors F : EVAP canister
7. Camshaft position sensor (CMP sensor) g : Malfunction indicator lamp
8. ABS control module h : Fuel pump relay
9. Crankshaft position sensor (CKP sensor) (if equipped) i : Main relay
10. Power steering pressure switch (PSP switch) j : Oxygen sensor heater relay (if equipped)
11. CO adjusting resistor (if equipped)
12. Monitor connector (if equipped)
13. Transmission range switch (A/T)
14. Knock sensor
NOTE:
Above figure shows left-hand steering vehicle. For right-hand steering vehicle, parts with (*) are
installed at the side of symmetry. 
         
        
        
     
        
        Page 375 of 656
6E2-42 ENGINE AND EMISSION CONTROL SYSTEM (SEQUENTIAL MULTIPORT FUEL INJECTION FOR H27 ENGINE)
3) Check resistance between each two terminals as in table
below.
If check results are as specified, proceed to next operation
check. If not, replace.
Main relay resistance:
4) Check that there is continuity between terminals “A” and “B”
when battery is connected to terminals “C” and “D”.
If malfunction is found, replace.
Fuel pump relay
INSPECTION
1) Disconnect negative (–) cable at battery.
2) Remove fuel pump relay (2) from connector.
3) Structure of fuel pump relay is the same as that of main
relay.
Check its resistance and operation using the same proce-
dure as that for main relay.
If malfunction is found, replace. TERMINALS RESISTANCE
Between “A” and “B”∞
∞∞ ∞ (Infinity)
Between “C” and “D”
79 – 95 Ω
ΩΩ Ω (at 20
°C (68°F))
1. Main relay
3. Fuse box
4. Instrument panel
[A]: Left-hand steering vehicle
[B]: Right-hand steering vehicle