Part 2

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

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0171 OR P0172)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(e) Read the DTCs.

Result





HINT
If any DTCs other than P0171 or P0172 are output, troubleshoot those DTCs first.

B -- GO TO DTC CHART SFI System
A -- Continue to next step.

2. CHECK PCV HOSE CONNECTIONS

(a) Check the PCV hose connections Components.

OK:

PCV valve and hose are connected correctly and are not damaged.

NG -- REPAIR OR REPLACE PCV HOSE
OK -- Continue to next step.

3. CHECK INTAKE SYSTEM

(a) Check the intake system for vacuum leaks Intake System.

OK:

No leaks in intake system.

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

4. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION VOLUME)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Put the engine in inspection mode (maintenance mode) Component Tests and General Diagnostics.

(e) Start the engine.

(f) Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.

HINT
During charging control, the engine speed is set at idle. Therefore, the engine speed does not increase when depressing the accelerator pedal. In this case, warm up the engine after charging control has completed.

(g) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / Data List / Gas AF Control / AFS Voltage B1S1 and O2S B1S2.

(h) Perform the Control the Injection Volume operation with the engine idling.

(i) Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS Voltage B1S1 and O2S B1S2) displayed on the Techstream.

HINT
- Change the fuel injection volume within the range of -12% to +12%. The injection volume can be changed in fine gradations.
- The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor has a maximum output delay of approximately 20 seconds.
- If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.





Result





Lean: During the Control the Injection Volume Active Test, the air fuel ratio sensor output voltage (AFS Voltage B1S1) is consistently higher than 3.4 V, and the heated oxygen sensor output voltage (O2S B1S2) is consistently below 0.4 V.

Rich: During the Control the Injection Volume Active Test, the AFS Voltage B1S1 is consistently below 3.1 V, and the O2S B1S2 is consistently higher than 0.55 V.

Lean/Rich: During the Control the Injection Volume Active Test, the output voltage of the heated oxygen sensor alternates correctly.

HINT
Refer to "Data List / Active Test" [AFS Voltage B1S1 and O2S B1S2] Data List / Active List.

B -- INSPECT AIR FUEL RATIO SENSOR NO.2 (HEATER RESISTANCE)
A -- Continue to next step.

5. READ VALUE USING TECHSTREAM (COOLANT TEMP)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / Coolant Temp.

(e) Read Coolant Temp twice, when the engine is both cold and warmed up.

Standard:





NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR Removal
OK -- Continue to next step.

6. READ VALUE USING TECHSTREAM (MAF)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Put the engine in inspection mode (maintenance mode) Component Tests and General Diagnostics.

(e) Start the engine.

(f) Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / MAF, Coolant Temp and Engine Speed.

(g) Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.

(h) Read MAF with the engine speed at 2500 rpm.

HINT
During charging control, the engine speed is set at idle. Therefore, the engine speed does not increase when depressing the accelerator pedal. In this case, read the Data List after charging control has completed.

Standard:





NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION)
OK -- Continue to next step.

7. CHECK FUEL PRESSURE

(a) Check the fuel pressure Fuel System.

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