Toyota Tundra. Manual — part 1187

Standard voltage

TESTER CONNECTION SPECIFIED CONDITION

NG : REPLACE ECM (See REMOVAL )

Fig. 101: Identifying R7 Connector Terminals

OK : Go to next step

14. REPLACE FUEL PUMP ECU

a. Replace the fuel pump ECU (See FUEL PUMP ECU ).

15. CONFIRM WHETHER DTC OUTPUT RECURS

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch ON.

c. Turn the Techstream ON.

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

e. Start the engine and idle it for 5 minutes.

f. Drive the vehicle in an urban area for approximately 10 minutes.

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

h. Read the DTCs.

Result

RESULT CHART

Tester Connection

Condition

Specified Condition

R7-1 (FPC) - R7-3 (E) Engine cranking

2.8 V or higher

Display (DTC Output) Proceed To

No output

A

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

B : GO TO DTC CHART (See DIAGNOSTIC TROUBLE CODE CHART )

A : END

16. CHECK HARNESS AND CONNECTOR (CIRCUIT OPENING RELAY (C/OPN) - IGN FUSE,

INTEGRATION RELAY)

a. Remove the circuit opening relay (C/OPN) from the engine room relay block.

b. Remove the IGN fuse from the engine room relay block.

c. Remove the integration relay from the engine room junction block.

d. Disconnect the 1B integration relay connector.

e. Measure the resistance according to the value(s) in the table below.

Standard resistance (Check for open)

TESTER CONNECTION SPECIFIED CONDITION

Standard resistance (Check for short)

TESTER CONNECTION SPECIFIED CONDITION

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

Other DTCs

B

Tester Connection

Condition Specified Condition

C/OPN relay (2) - IGN fuse (2) Always

Below 1 ohms

C/OPN relay (5) - 1B-4

Always

Below 1 ohms

Tester Connection

Condition Specified Condition

C/OPN relay (2) or IGN fuse (2) - Body ground Always

10 kohms or more

C/OPN relay (5) or 1B-4 - Body ground

Always

10 kohms or more

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

Fig. 102: Identifying Circuit Opening Relay (C/OPN)

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

OK : GO TO ECM POWER SOURCE CIRCUIT

DTC P0300 RANDOM/MULTIPLE CYLINDER MISFIRE DETECTED; DTC P0301 CYLINDER 1
MISFIRE DETECTED; DTC P0302 CYLINDER 2 MISFIRE DETECTED; DTC P0303 CYLINDER 3
MISFIRE DETECTED; DTC P0304 CYLINDER 4 MISFIRE DETECTED; DTC P0305 CYLINDER 5
MISFIRE DETECTED; DTC P0306 CYLINDER 6 MISFIRE DETECTED

DESCRIPTION

Fig. 103: VVT Sensor & ECM Communication Diagram

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. High HC
concentration levels can cause increase in exhaust emission levels. Extremely high concentrations of HC can
also cause increases in the Three-Way Catalytic Converter (TWC) temperature, which may cause damage to the
TWC. To prevent this increase in emissions and to limit the possibility of thermal damage, the ECM monitors
the misfire rate. When the temperature of the TWC reaches the point of thermal degradation, the ECM blinks
the MIL. To monitor misfires, the ECM uses both the VVT sensor and the Crankshaft Position (CKP) sensor.
The VVT sensor is used to identify any misfiring cylinders and the CKP sensor is used to measure variations in
the crankshaft rotation speed. Misfires are counted when the crankshaft rotation speed variations exceed
predetermined thresholds. If the misfire count exceeds the threshold levels, the ECM illuminates the MIL and
sets a DTC.

DTC TROUBLE DETECTION CONDITION CHART

DTC

No.

DTC Detection Condition

Trouble Area

P0300

Simultaneous misfiring of several cylinders occurs and one of
following conditions below is detected (2 trip detection logic):



High temperature misfire occurs in Three-Way Catalytic
Converter (TWC) (MIL blinks)



Emission deterioration misfire occurs (MIL illuminates)



Open or short in engine
wire harness



Connector connection



Vacuum hose
connections



Ignition system



Injector



Fuel pressure



Mass Air Flow (MAF)
meter



Engine Coolant

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra