Part 3

2ZR-FXE ENGINE CONTROL: SFI SYSTEM: P0171, P0172: System Too Lean (Bank 1)
P0172 - System Too Rich (Bank 1) (Continued)

8. CHECK FOR EXHAUST GAS LEAK

(a) Check for exhaust gas leaks.

OK:

No gas leaks

NG -- REPAIR OR REPLACE EXHAUST SYSTEM
OK -- Continue to next step.

9. CHECK FOR SPARK (SPARK TEST)

(a) Perform a spark test Testing and Inspection.

HINT
- If the result of the spark test is normal, proceed to the next step.
- If the spark plugs or ignition system malfunctions, engine misfire may occur. The misfire count can be read using the Techstream. Enter the following menus: Powertrain / Engine and ECT / Data List / Gas Misfire / Cylinder #1 Misfire Count (to Cylinder #4 Misfire Count).

NEXT -- Continue to next step.

10. INSPECT FUEL INJECTOR ASSEMBLY (INJECTION AND VOLUME)

(a) Check the injection and volume.

HINT
- Refer to the fuel injector assembly inspection procedure Testing and Inspection.
- If the injectors malfunction, engine misfire may occur. The misfire count can be read using the Techstream. Enter the following menus: Powertrain / Engine and ECT / Data List / Gas Misfire / Cylinder #1 Misfire Count (to Cylinder #4 Misfire Count).

Result





B -- CHECK WHETHER DTC OUTPUT RECURS (DTC P0171 OR P0172)

A -- REPLACE FUEL INJECTOR ASSEMBLY Removal

11. INSPECT AIR FUEL RATIO SENSOR NO.2 (HEATER RESISTANCE)

(a) Inspect the air fuel ratio sensor Air Fuel Ratio Sensor.

NG -- REPLACE AIR FUEL RATIO SENSOR NO.2 Removal
OK -- Continue to next step.

12. CHECK TERMINAL VOLTAGE (POWER SOURCE OF AIR FUEL RATIO SENSOR) P0031

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - EFI MAIN RELAY)
OK -- Continue to next step.

13. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM) P2237

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

14. REPLACE AIR FUEL RATIO SENSOR NO.2

(a) Replace the air fuel ratio sensor Removal.

NEXT -- Continue to next step.