Code No. P0170: Abnormal Fuel System

OPERATION

Refer to Code No. P0201: No. 1 Injector System .
Refer to Code No. P0202: No. 2 Injector System .
Refer to Code No. P0203: No. 3 Injector System .
Refer to Code No. P0204: No. 4 Injector System .

FUNCTION

If the fuel system goes out of order, the fuel correction valve will become larger.
The engine-ECU checks whether the fuel trim value is within a specified range.

TROUBLE JUDGMENT

Check Condition

In learning the air-fuel ratio.

Judgment Criterion

Long-term fuel trim has continued to be +12.5% or higher for 10 seconds.

Long-term fuel trim has continued to be -12.5% or lower for 10 seconds.

PROBABLE CAUSES

Failed intake air temperature sensor
Failed purge control solenoid valve
Failed injector
Air drawn in from gaps in gasket, seals, etc.
Failed engine coolant temperature sensor
Failed air flow sensor
Failed oxygen sensor (front)
Failed barometric pressure sensor
Exhaust leak
Incorrect fuel pressure
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q. Is any other diagnosis code than P0170 output?

	Inspection Chart for Diagnosis Code (Refer to ).

	Go to Step 2 .

STEP 2. M.U.T.-III data list

Refer to Data List Reference Table .

Item No. 6: Intake air temperature sensor
Item No. 8: Engine coolant temperature sensor
Item No. 80: Air flow sensor

Q. Are the check results normal?

	Go to Step 3 .

	Perform the diagnosis code classified check procedure for the sensor that has shown an abnormal data value (Refer to Inspection Chart for Diagnosis Code ).

STEP 3. M.U.T.-III data list

Refer to Data List Reference Table .

Item No. 79: Barometric pressure sensor

Q. Is the check result normal?

	Go to Step 4 .

	Replace the engine-ECU then perform the variant coding (Refer to GROUP 00 - Precautions Before Service - How to Perform Variant Coding ).

STEP 4. Check throttle body (throttle valve portion) for contamination.

Q. Is the check result normal?

	Go to Step 5 .

	Clean throttle body (throttle valve portion) (Refer to ).

STEP 5. Check for intake of air from gaps in gasket, seals, etc.

Q. Is the check result normal?

	Go to Step 6 .

	Repair for intake of air from gaps in gasket, seals, etc.

STEP 6. Check for leakage of exhaust emission from exhaust manifold.

Q. Is the check result normal?

	Go to Step 7 .

	Repair for leakage of exhaust emission from exhaust manifold.

STEP 7. M.U.T.-III data list

Refer to Data List Reference Table .

Item No. 11: Oxygen sensor (front)

Q. Is the check result normal?

	Go to Step 8 .

	Check oxygen sensor (front) system (Refer to Code No. P0130 ).

STEP 8. Connector Check: Injector connectors

A-101 (No. 1 injector connector).
A-102 (No. 2 injector connector).
A-123 (No. 3 injector connector).
A-121 (No. 4 injector connector).

Q. Are the check results normal?

Go to Step 9 .

Repair or replace the connector.

STEP 9. Check injector itself.

Check Injector itself (Refer to ).

Q. Is the check result normal?

	Go to Step 10 .

	Replace the injector.

STEP 10. Connector check: B-206 engine control relay connector and A-34 engine-ECU connector

Q. Is the check result normal?

Go to Step 11 .

Repair or replace the connector.

STEP 11. Check harness between B-206 engine control relay connector and injector connectors.

Check harness between B-206 (terminal No. 4) engine control relay connector and A-101 (terminal No. 1) No. 1 injector connector.
Check harness between B-206 (terminal No. 4) engine control relay connector and A-102 (terminal No. 1) No. 2 injector connector.
Check harness between B-206 (terminal No. 4) engine control relay connector and A-123 (terminal No. 1) No. 3 injector connector.
Check harness between B-206 (terminal No. 4) engine control relay connector and A-121 (terminal No. 1) No. 4 injector connector.

note Before checking harness, check intermediate connector A-36 and B-212, and repair if necessary.

Check power supply line for damage.

Q. Are the check results normal?

Go to Step 12 .

Repair the damaged harness wire.

STEP 12. Check harness between injector connector and A-34 engine-ECU connector.

Check harness between A-101 (terminal No. 2) No. 1 injector connector and A-34 (terminal No. 8) engine-ECU connector.
Check harness between A-102 (terminal No. 2) No. 2 injector connector and A-34 (terminal No. 9) engine-ECU connector.
Check harness between A-123 (terminal No. 2) No. 3 injector connector and A-34 (terminal No. 23) engine-ECU connector.
Check harness between A-121 (terminal No. 2) No. 4 injector connector and A-34 (terminal No. 24) engine-ECU connector.

Check earthing line for damage.

Q. Are the check results normal?

Go to Step 13 .

Repair the damaged harness wire.

STEP 13. Check purge control solenoid valve itself.

Check purge control solenoid valve itself (Refer to GROUP 17 - Emission Control System - Evaporative Emission Control System - Purge Control Solenoid Valve ).

Q. Is the check result normal?

	Go to Step 14 .

	Replace the purge control solenoid valve.

STEP 14. Fuel pressure measurement.

Fuel pressure measurement (Refer to Fuel Pressure Test ).

Q. Is the check result normal?

	Replace the engine-ECU then perform the variant coding (Refer to GROUP 00 - Precautions Before Service - How to Perform Variant Coding ).

	Repair the fuel pressure.