Toyota Sequoia Limited

2001 ENGINE PERFORMANCE Theory & Operation

A

WT Sensors (Cam

Wl, 2

shaft Position Sensors)

o

o

Crankshaft

Position

Sensor

NE

ECM o

o

Various

o

Sensors

IGT3

IGT4

IGT5

IGT6

G99G52361

IGT1

IGT2

IGT3

IGT4

IGT5

IGT6

Ignition Coil

No. 1 Cylinder

No. 2 Cylinder

No. 3 Cylinder

No. 4 Cylinder

No. 5 Cylinder

No. 6 Cylinder

G99G52361

Fig. 55: Distributorless Ignition System Schematic (Avalon, Highlander 3.0L V6 & Sienna) Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Camry 2.2L 4-Cyl. CNG & Gasoline Models, & Camry Solara 2.2L 4-Cyl.

Distributorless Ignition System (DIS) uses Engine Control Module (ECM) for determining ignition timing (spark advance). ECM may determine ignition timing (spark advance) based on various input signals, engine RPM and knock sensor input signal (gasoline models only).

Conventional distributor and pick-up coil have been replaced by Camshaft Position (CMP) sensor and Crankshaft Position (CKP) sensor. CMP sensor and CKP sensor deliver input signals to ECM. ECM detects standard crankshaft position based on CMP sensor input signals and actual crankshaft position, and engine speed by CKP sensor input signals.

CMP sensor is located at timing belt end of cylinder head, on firewall side of engine. See Fig. 10 and Fig. 11 . CKP sensor is located behind lower timing belt cover, near crankshaft sprocket. See Fig. 10 and Fig. 11 . For knock sensor location, see REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

The ECM uses 2 ignition primary control signals to ignitor for ignition coils. DIS uses 2 ignition coils with internal ignitors to fire 2 cylinders simultaneously using same ignition coil. See Fig. 56 . Cylinders No. 1 and 4 fire together and cylinders No. 2 and 3 fire together. Cylinder No. 1 is front cylinder at timing belt end of engine and cylinder No. 4 is rear cylinder at flywheel end of engine. Ignition coils are mounted on end of cylinder head, just below valve cover. ECM monitors IGF circuit at ignitor to ensure ignition coils have fired. ECM stops fuel injection as a fail-safe function if ECM does not receive IGF signal.

2001 ENGINE PERFORMANCE Theory & Operation

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