Code No. P0170: Abnormal Fuel System <DOHC>

function

If the fuel system goes out of order, the fuel correction value will become larger.

The engine-A/T-ECU checks whether the fuel correction value is within the standard limits.

TROUBLE JUDGMENT

Check Condition

Engine: Learning air-fuel ratio

Judgment Criterion

Fuel injection amount correction value remains unusually low for more than 5 seconds,

Fuel injection amount correction value remains unusually high for more than 5 seconds.

PROBABLE CAUSE

Failed fuel supply system

Failed oxygen sensor

Failed intake air temperature sensor

Failed air flow sensor

Failed purge control solenoid valve

Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. MUT-II/III self-diag code

Q: Is any other diagnosis code than P0170 output?

YES: Inspection Chart for Diagnosis Code (Refer to

).
NO: Go to Step 2

STEP 2. MUT-II/III data list

Refer to Data list reference table .

Item 12: Air flow sensor

Item 13: Intake air temperature sensor

Item 21: Engine coolant temperature sensor

Item 22: Barometric pressure sensor

Q: Are the check results normal?

YES: Go to Step 3

.
NO: Perform the Diagnosis Code Classified Check Procedure for the sensor that has shown an abnormal data value (Refer to Inspection Chart for Diagnosis Codes

STEP 3. Check for intake of air from intake hose and intake manifold.

Q: Is the check result normal?

YES: Go to Step 4

.
NO: Repair.

STEP 4. Check for leakage of exhaust emission from exhaust manifold.

Q: Is the check result normal?

YES: Go to Step 5

.
NO: Repair.

STEP 5. Check throttle body (throttle valve portion) for contamination.

Q: Is the check result normal?

YES: Go to Step 6

.
NO: Clean throttle body (throttle valve portion) (Refer to

STEP 6. MUT-II/III data list

Refer to Data list reference table .

Item 11: Oxygen sensor

Q: Is the check result normal?

YES: Go to Step 7

.
NO: Check oxygen sensor system (Refer to Code No. P0130

STEP 7. Check injector itself.

Check Injector itself (Refer to ).

Q: Is the check result normal?

YES: Go to Step 8

.
NO: Replace injector.

STEP 8. Check purge control solenoid valve itself.

Check purge control solenoid valve itself [Refer to GROUP 17 - Emission Control System - Evaporative Emission Control System ].

Q: Is the check result normal?

YES: Go to Step 9

.
NO: Replace purge control solenoid valve.

STEP 9. Measure fuel pressure.

Measure fuel pressure (Refer to ).

Q: Is the check result normal?

YES: Replace engine-A/T-ECU.
NO: Repair.


Code No. P0170: Abnormal Fuel System <DOHC>

function If the fuel system goes out of order, the fuel correction value will become larger. The engine-A/T-ECU checks whether the fuel correction value is within the standard limits.
TROUBLE JUDGMENT Check Condition Engine: Learning air-fuel ratio Judgment Criterion Fuel injection amount correction value remains unusually low for more than 5 seconds, or Fuel injection amount correction value remains unusually high for more than 5 seconds.
PROBABLE CAUSE Failed fuel supply system Failed oxygen sensor Failed intake air temperature sensor Failed air flow sensor Failed purge control solenoid valve Failed engine-A/T-ECU
	DIAGNOSIS PROCEDURE

	STEP 1. MUT-II/III self-diag code Q: Is any other diagnosis code than P0170 output? YES: Inspection Chart for Diagnosis Code (Refer to ). NO: Go to Step 2 .
	STEP 2. MUT-II/III data list Refer to Data list reference table . Item 12: Air flow sensor Item 13: Intake air temperature sensor Item 21: Engine coolant temperature sensor Item 22: Barometric pressure sensor Q: Are the check results normal? YES: Go to Step 3 . NO: Perform the Diagnosis Code Classified Check Procedure for the sensor that has shown an abnormal data value (Refer to Inspection Chart for Diagnosis Codes ).
	STEP 3. Check for intake of air from intake hose and intake manifold. Q: Is the check result normal? YES: Go to Step 4 . NO: Repair.
	STEP 4. Check for leakage of exhaust emission from exhaust manifold. Q: Is the check result normal? YES: Go to Step 5 . NO: Repair.
	STEP 5. Check throttle body (throttle valve portion) for contamination. Q: Is the check result normal? YES: Go to Step 6 . NO: Clean throttle body (throttle valve portion) (Refer to ).
	STEP 6. MUT-II/III data list Refer to Data list reference table . Item 11: Oxygen sensor Q: Is the check result normal? YES: Go to Step 7 . NO: Check oxygen sensor system (Refer to Code No. P0130 ).
	STEP 7. Check injector itself. Check Injector itself (Refer to ). Q: Is the check result normal? YES: Go to Step 8 . NO: Replace injector.
	STEP 8. Check purge control solenoid valve itself. Check purge control solenoid valve itself [Refer to GROUP 17 - Emission Control System - Evaporative Emission Control System ]. Q: Is the check result normal? YES: Go to Step 9 . NO: Replace purge control solenoid valve.
	STEP 9. Measure fuel pressure. Measure fuel pressure (Refer to ). Q: Is the check result normal? YES: Replace engine-A/T-ECU. NO: Repair.