DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION EC-991
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Revision: 2005 July 2005 FX
3. CHECK HEATED OXYGEN SENSOR 1 CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect corresponding heated oxygen sensor 1 (HO2S1) harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between ECM terminal and HO2S1 terminal as follows. Refer to Wiring Diagram.
5. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.
6. Check harness continuity between HO2S1 terminal 4 and ECM terminal 78.
7. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4. CHECK FUEL PRESSURE
1. Release fuel pressure to zero. Refer to EC-789, "
FUEL PRESSURE RELEASE" .
2. Install fuel pressure gauge and check fuel pressure. Refer to EC-789, "
FUEL PRESSURE CHECK" .
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
DTC Te r m i n a l s
Bank
ECM Sensor
P0171 16 1 1
P0174 35 1 2
Continuity should exist.
PBIB1521E
DTC Te r m i n a l s
Bank
ECM Sensor
P0171 16 1 1
P0174 35 1 2
Continuity should not exist.
Continuity should exist.
At idling: 350 kPa (3.57 kg/cm2 , 51 psi)
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION EC-993
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Revision: 2005 July 2005 FX
8. CHECK FUNCTION OF INJECTOR-I
Without CONSULT-II
1. Turn ignition switch OFF.
2. Disconnect harness connectors F21, F201 (bank 1) and F41, F221 (bank 2).
3. Turn ignition switch ON.
4. Check voltage between the following; harness connector F21 terminal 5 and ground,
harness connector F41 terminal 5 and ground
with CONSULT-II or tester.
5. Turn ignition switch OFF.
6. Disconnect ECM harness connector.
7. Check harness continuity between the following terminals.
8. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 9.
NG >> Perform trouble diagnosis for INJECTOR CIRCUIT, refer to EC-1351
.
Voltage: Battery voltage
Cylinder Harness connector terminal ECM terminal
1 F21 terminal 3 23
3 F21 terminal 2 22
5 F21 terminal 1 21
7 F21 terminal 6 44
2 F41 terminal 3 42
4 F41 terminal 2 41
6 F41 terminal 1 40
8 F41 terminal 6 63
Continuity should exist.
PBIB2561E
PBIB0180E
EC-994
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DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
Revision: 2005 July 2005 FX
9. CHECK FUNCTION OF INJECTOR-II
Provide battery voltage between the following terminals, and then
interrupt it. Listen to each injector operating sound.
OK or NG
OK >> GO TO 10.
NG >> Perform trouble diagnosis for INJECTOR CIRCUIT, refer to EC-1351
.
10. CHECK INJECTOR
1. Turn ignition switch OFF.
2. Confirm that the engine is cooled down and there are no fire hazards near the vehicle.
3. Disconnect all injector harness connectors.
4. Remove injector gallery assembly. Refer to EM-192, "
FUEL INJECTOR AND FUEL TUBE" .
Keep fuel hose and all injectors connected to injector gallery.
5. For DTC P0171, reconnect injector harness connectors on bank 1. For DTC P0174, reconnect injector harness connectors on bank 2.
6. Disconnect all ignition coil harness connectors.
7. Prepare pans or saucers under each injector.
8. Crank engine for about 3 seconds. For DTC P0171, make sure that fuel sprays out from injectors
on bank 1.
For DTC P0174, make sure that fuel sprays out from injectors
on bank 2.
OK or NG
OK >> GO TO 11.
NG >> Replace injectors from which fuel does not spray out. Always replace O-ring with new ones.
11 . CHECK INTERMITTENT INCIDENT
Refer to EC-854, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>> INSPECTION END
Cylinder Harness connector terminal
(+) (–)
1
F201 5 3
32
51
76
2
F221 5 3
42
61
86
Operating sound should exist.
PBIB2449E
Fuel should be sprayed evenly for each injector.
PBIB1726E
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION EC-995
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Revision: 2005 July 2005 FX
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTIONPFP:16600
On Board Diagnosis LogicABS00E54
With the Air-Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The
ECM calculates the necessary compensation to correct the offset between the actual and the theoretical
ratios.
In case the amount of the compensation value is extremely large (The actual mixture ratio is too rich.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC Confirmation ProcedureABS00E55
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON and select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CON- SULT-II.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Select “DATA MONITOR” mode with CONSULT-II.
6. Start engine again and let it idle for at least 10 minutes. The 1st trip DTC P0172, P0175 should be detected at this stage,
if a malfunction exists. If so, go to EC-999, "
Diagnostic Proce-
dure" .
NOTE:
If 1st trip DTC is not detected during above procedure, perform-
ing the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar conditions to (1st trip) Freeze Frame Data for a certain time. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Data means the vehicle operation that the following con-
ditions should be satisfied at the same time.
7. If it is difficult to start engine at step 6, the fuel injection system has a malfunction, too.
8. Crank engine while depressing accelerator pedal.
Sensor Input Signal to ECM ECM function Actuator
Heated oxygen sensor 1 Density of oxygen in exhaust gas
(Mixture ratio feedback signal) Fuel injection control Fuel injector
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0172
0172
(Bank 1) Fuel injection system too
rich
Fuel injection system does not operate properly.
The amount of mixture ratio compensation is too
large. (The mixture ratio is too rich.)
Heated oxygen sensor 1
Fuel injector
Exhaust gas leaks
Incorrect fuel pressure
Mass air flow sensor
P0175
0175
(Bank 2)
SEF968Y
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Engine coolant temperature
(T) condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F).
EC-996
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DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
Revision: 2005 July 2005 FX
If engine starts, go to EC-999, "Diagnostic Procedure" . If engine does not start, remove ignition plugs and
check for fouling, etc.
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Disconnect mass air flow sensor harness connector. Then restart and run engine for at least 5 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness con- nector.
5. Select Service $03 with GST. Make sure DTC P0102 is detected.
6. Select Service $04 with GST and erase the DTC P0102.
7. Start engine again and let it idle for at least 10 minutes.
8. Select Service $07 with GST. The 1st trip DTC P0172 or P0175 should be detected at this stage, if a malfunction exists. If so, go
to EC-999, "
Diagnostic Procedure" .
NOTE:
If 1st trip DTC is not detected during above procedure, performing the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar conditions to (1st trip) Freeze Frame Data for a certain time. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Data means the vehicle operation that the following con-
ditions should be satisfied at the same time.
9. If it is difficult to start engine at step 7, the fuel injection system has a malfunction.
10. Crank engine while depressing accelerator pedal. If engine starts, go to EC-999, "
Diagnostic Procedure" . If engine does not start, remove spark plugs and
check for fouling, etc.
PBIB1502E
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Engine coolant temperature
(T) condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F).
EC-1000
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DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
Revision: 2005 July 2005 FX
3. CHECK HEATED OXYGEN SENSOR 1 CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect corresponding heated oxygen sensor 1 (HO2S1) harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between ECM terminal and HO2S1 terminal as follows. Refer to Wiring Diagram.
5. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.
6. Check harness continuity between HO2S1 terminal 4 and ECM terminal 78.
7. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4. CHECK FUEL PRESSURE
1. Release fuel pressure to zero. Refer to EC-789, "
FUEL PRESSURE RELEASE" .
2. Install fuel pressure gauge and check fuel pressure. Refer to EC-789, "
FUEL PRESSURE CHECK" .
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
DTC Terminals
Bank
ECM Sensor
P0172 16 1 1
P0175 35 1 2
Continuity should exist.
PBIB1521E
DTC Terminals
Bank
ECM Sensor
P0172 16 1 1
P0175 35 1 2
Continuity should not exist.
Continuity should exist.
At idling: 350 kPa (3.57 kg/cm2 , 51 psi)
EC-1002
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DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
Revision: 2005 July 2005 FX
8. CHECK FUNCTION OF INJECTOR-I
Without CONSULT-II
1. Turn ignition switch OFF.
2. Disconnect harness connectors F21, F201 (bank 1) and F41, F221 (bank 2).
3. Turn ignition switch ON.
4. Check voltage between the following; harness connector F21 terminal 5 and ground,
harness connector F41 terminal 5 and ground
with CONSULT-II or tester.
5. Turn ignition switch OFF.
6. Disconnect ECM harness connector.
7. Check harness continuity between the following terminals.
8. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 9.
NG >> Perform trouble diagnosis for INJECTOR CIRCUIT, refer to EC-1351
.
Voltage: Battery voltage
Cylinder Harness connector terminal ECM terminal
1 F21 terminal 3 23
3 F21 terminal 2 22
5 F21 terminal 1 21
7 F21 terminal 6 44
2 F41 terminal 3 42
4 F41 terminal 2 41
6 F41 terminal 1 40
8 F41 terminal 6 63
Continuity should exist.
PBIB2561E
PBIB0180E
DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION EC-1003
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Revision: 2005 July 2005 FX
9. CHECK FUNCTION OF INJECTOR-II
Provide battery voltage between the following terminals, and then
interrupt it. Listen to each injector operating sound.
OK or NG
OK >> GO TO 10.
NG >> Perform trouble diagnosis for INJECTOR CIRCUIT, refer to EC-1351
.
10. CHECK INJECTOR
1. Turn ignition switch OFF.
2. Confirm that the engine is cooled down and there are no fire hazards near the vehicle.
3. Remove injector gallery assembly. Refer to EM-192, "
FUEL INJECTOR AND FUEL TUBE" .
Keep fuel hose and all injectors connected to injector gallery.
4. Disconnect all injector harness connectors.
5. Disconnect all ignition coil harness connectors.
6. Prepare pans or saucers under each injectors.
7. Crank engine for about 3 seconds. Make sure fuel does not drip from injector.
OK or NG
OK (Does not drip.)>>GO TO 11.
NG (Drips.)>>Replace the injectors from which fuel is dripping. Always replace O-ring with new one.
11 . CHECK INTERMITTENT INCIDENT
Refer to EC-854, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>> INSPECTION END
Cylinder Harness connector terminal
(+) (–)
1
F201 5 3
32
51
76
2
F221 5 3
42
61
86
Operating sound should exist.
PBIB2449E