DTC Logic
DTC DETECTION LOGIC
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 A/F 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 lean.), the ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
Sensor | Input signal to ECM | ECM function | Actuator |
A/F sensor 1 | Density of oxygen in exhaust gas (Mixture ratio feedback signal) | Fuel injection control | Fuel injector |
DTC No. | CONSULT screen terms (Trouble diagnosis content) | DTC detecting condition | Possible cause |
P0171 | FUEL SYS-LEAN-B1 (System too lean bank 1) |
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DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE-1
Is it difficult to start engine? YES >> GO TO 3.
NO >> GO TO 4.
3.RESTART ENGINE
If it is difficult to start engine, the fuel injection system has a malfunction, too.
Crank engine while depressing accelerator pedal.
NOTE:
When depressing accelerator pedal three-fourths (3/4) or more, the control system does not start the engine. Do not depress accelerator pedal too much.
Does engine start? YES >> Proceed to EC-247, "Diagnosis Procedure".
NO >> Check exhaust and intake air leak visually.
4.PERFORM DTC CONFIRMATION PROCEDURE-2
Is 1st trip DTC detected? YES >> Proceed to EC-247, "Diagnosis Procedure".
NO >> GO TO 5.
5.PERFORM DTC CONFIRMATION PROCEDURE-3
Hold the accelerator pedal as steady as possible.
CAUTION:
Always drive vehicle at a safe speed.
Is 1st trip DTC detected? YES >> Proceed to EC-247, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis Procedure
1.CHECK EXHAUST GAS LEAK
Is exhaust gas leak detected? YES >> Repair or replace error-detected parts.
NO >> GO TO 2.
2.CHECK FOR INTAKE AIR LEAK
Intake air leak detected? YES >> Repair or replace error-detected parts.
NO >> GO TO 3.
3.CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT
*1: Except California
*2: For California
*1: Except California
*2: For California
Is the inspection result normal? YES >> GO TO 4.
NO >> Repair or replace error-detected parts.
4.CHECK FUEL PRESSURE
Check fuel pressure. Refer to EC-143, "Work Procedure".
Is the inspection result normal? YES >> GO TO 6.
NO >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check fuel hoses and fuel tubes for clogging. Refer to EM-40, "Exploded View".
Is the inspection result normal? YES >> Replace “fuel filter and fuel pump assembly”. Refer to FL-6, "Exploded View".
NO >> Repair or replace error-detected parts.
6.CHECK MASS AIR FLOW SENSOR
With CONSULT
With GST
Is the measurement value within the specification? YES >> GO TO 7.
NO >> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or grounds. Refer to EC-186, "DTC Logic".
7.CHECK FUNCTION OF FUEL INJECTOR
With CONSULT
Without CONSULT
Clicking noise should be heard.
Is the inspection result normal? YES >> GO TO 8.
NO >> Perform trouble diagnosis for “FUEL INJECTOR”. Refer to EC-450, "Component Function Check".
8.CHECK FUEL INJECTOR
Keep fuel hose and all fuel injectors connected to fuel tube.
Fuel should be sprayed evenly for each fuel injector.
Is the inspection result normal?
YES >> Check intermittent incident. Refer to GI-39, "Intermittent Incident".
NO >> Replace fuel injectors from which fuel does not spray out. Always replace O-ring with new ones. Refer to EM- 40, "Removal and Installation".
Dlc branch line circuit
Diagnosis procedure
1.Check connector
Turn the ignition switch off.
Disconnect the battery cable from the negative terminal.
Check the terminals and connectors of the data link connector for
damage, bend and loose connection
(connector side and harness side).
Is the inspection resul ...
Coil spring
Exploded View
Upper rubber seat
Coil spring
Lower rubber seat
Rear suspension beam
Front
Removal and Installation
REMOVAL
Set a suitable jack under the rear suspension beam.
CAUTION:
At this step, the jack must be set only for supporting the removal
procedure. For d ...
Ecu diagnosis information
Abs actuator and electric unit
(control unit)
Reference Value
VALUES ON THE DIAGNOSIS TOOL
CAUTION:
The display shows the control unit calculation data, so a
normal value might be displayed even in the
event the output circuit (harness) is open or short-circuited.
...