Toyota Tundra. Manual — part 1359

4. READ VALUE USING TECHSTREAM (COOLANT TEMP)

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch to ON and turn the Techstream ON.

c. Enter the following menus: Powertrain/Engine and ECT/Data List/All Data/Coolant Temp.

d. Read the Coolant Temp twice, when the engine is both cold and warmed up.

Standard:

With cold engine: Same as ambient air temperature.

With warm engine: Between 75°C and 100°C (167°F and 212°F).

NG : REPLACE ENGINE COOLANT TEMPERATURE SENSOR (See REMOVAL )

OK : Go To Next Step

5. CHECK PCV HOSE CONNECTIONS

a. Check the PCV hose connections.

OK: PCV hose is connected correctly and is not damaged.

NG : REPAIR OR REPLACE PCV HOSE

OK : Go To Next Step

6. CHECK AIR INDUCTION SYSTEM

a. Check the air induction system for vacuum leakage. (See ON-VEHICLE INSPECTION ).

OK: No leakage from air induction system.

NG : REPAIR OR REPLACE AIR INDUCTION SYSTEM

OK : Go To Next Step

7. CHECK FOR SPARKS AND IGNITION (See INSPECTION PROCEDURE )

NG : REPAIR OR REPLACE IGNITION SYSTEM

OK : Go To Next Step

8. CHECK FOR EXHAUST GAS LEAK

a. Check for exhaust gas leak.

OK: No gas leakage.

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

NG : REPAIR OR REPLACE EXHAUST SYSTEM

OK : Go To Next Step

9. CHECK FUEL PRESSURE

a. Check the fuel pressure. (See ON-VEHICLE INSPECTION ).

NG : REPAIR OR REPLACE FUEL SYSTEM

OK : Go To Next Step

10. INSPECT FUEL INJECTOR (INJECTION AND VOLUME)

a. Check the injection volume. (See INSPECTION ).

NG : REPLACE FUEL INJECTOR . (See FUEL INJECTOR ).

OK : Go To Next Step

11. INSPECT AIR-FUEL RATIO SENSOR (HEATER RESISTANCE) (See INSPECTION

PROCEDURE )

NG : REPLACE AIR FUEL RATIO SENSOR (See REMOVAL )

OK : Go To Next Step

12. INSPECT INTEGRATION RELAY (A/F RELAY) (See INSPECTION PROCEDURE )

NG : REPLACE INTEGRATION RELAY (See ON-VEHICLE INSPECTION )

OK : Go To Next Step

13. CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM) (See INSPECTION

PROCEDURE )

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

OK : Go To Next Step

14. REPLACE AIR FUEL RATIO SENSOR

a. Replace the air fuel ratio sensor. (See REMOVAL ).

15. PERFORM CONFIRMATION DRIVING PATTERN

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

Fig. 96: Vehicle Speed Graph

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch to ON and turn the Techstream ON.

c. Clear DTCs. (See DTC CHECK/CLEAR ).

d. Switch the ECM from normal mode to check mode using the Techstream. (See CHECK MODE

PROCEDURE ).

e. Start the engine and warm it up with all the accessories switched OFF.

f. Drive the vehicle at between 60 km/h and 120 km/h (38 mph and 75 mph) and at an engine speed

of between 1400 RPM and 3200 RPM for 3 to 5 minutes.

HINT:

If the system is still malfunctioning, the MIL will be illuminated during step (f).

16. CHECK WHETHER DTC OUTPUT RECURS (DTC P0171, P0172, P0174 OR P0175)

a. Enter the following menus: Powertrain/Engine and ECT/Trouble Codes.

b. Read DTCs.

Result

RESULT REFERENCE

B : REPLACE ECM (See REMOVAL )

NOTE:

If the conditions in this test are not strictly followed, no malfunction
will be detected.

Result

Proceed To

No DTC is output

A

P0171, P0172, P0174 or P0175 is output

B

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

A : END

DTC P0230 FUEL PUMP PRIMARY CIRCUIT

DESCRIPTION

When a malfunction in the fuel pump circuit is detected, DTC P0230 is set.

The fuel pump circuit consists of the ECM, fuel pump and fuel pump ECU (which operates the fuel pump).
Based on the engine output, the ECM determines the fuel pump speed. The speed is then converted to a duty
signal and sent to the fuel pump ECU. Based on the signal sent from the ECM, the fuel pump ECU adjusts the
fuel pump operation speed between 3 settings. The fuel pump ECU also has a self-diagnosis function. Based on
the fuel pump circuit condition, the fuel pump ECU outputs a diagnostic signal (Dl) to the ECM, and the ECM
determines if there is a malfunction in the fuel pump circuit.

DTC DETECTION CONDITION AND TROUBLE AREA

MONITOR DESCRIPTION

To monitor the fuel pump circuit, the ECM checks the fuel pump control signal (FPC) and diagnostic signal
(Dl). The FPC voltage varies between approximately 0 V to approximately 12 V (duty signal). Based on the
condition of the fuel pump ECU malfunction, the Dl voltage varies between approximately 0 V and
approximately 12 V. The ECM then compares the variance of the FPC voltage and Dl voltage, and determines if
the fuel pump circuit is malfunctioning. When the ECM determines that the fuel pump circuit is malfunctioning,
a DTC is set immediately.

WIRING DIAGRAM

DTC

Code

DTC Detection Condition

Trouble Area

P0230

When either condition below is met (1 trip detection
logic):



When fuel pump is operating:



Remaining fuel is 17 L or more



Dl terminal output is low



When fuel pump is not operating:



Dl terminal output is high



Open or short in fuel pump
circuit



Fuel pump



Fuel pump ECU



ECM

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra