S00251
From Battery
Ignition Coil
Spark Plug
IGC1
IGC2
IGC3
GND
TAC
IGT1
IGT2
IGT3
IGF
To Tachometer
ECM
G
NE
Camshaft
Position
Sensor
Crankshaft
Position
Sensor
Various
Sensor
No.1 Cylinder
No.4 Cylinder
No.5 Cylinder
No.2 Cylinder
No.3 Cylinder
No.6 Cylinder
Igniter
DI–320
–
DIAGNOSTICS
ENGINE (5VZ–FE)
582
Author:
Date:
2003 TOYOTA TACOMA (RM1002U)
DTC
P0351
Ignition Coil ”A” Primary/Secondary Circuit
CIRCUIT DESCRIPTION
There DTCs indicate a malfunction related to primary circuit.
A Direct Ignition System (DIS) has been adopted. The DIS improves the ignition timing accuracy, reduces
high–voltage loss, and enhances the overall reliability of the ignition system by eliminating the distributor.
The DIS is a 2–cylinder simultaneous ignition system which ignites 2 cylinders simultaneously with one igni-
tion coil. In the 2–cylinder simultaneous ignition system, each of the 2 spark plugs is connected to the end
of the secondary winding. High voltage generated in the secondary winding is applied directly to the spark
plugs. The sparks of the 2 spark plugs passes simultaneously from the center electrode to the ground elec-
trode (No. 1, 5 and 3 cylinder) and from the ground electrode to the center electrode (No. 4, 2 and 6 cylinder).
The ECM determines the ignition timing end outputs the ignition signal (IGT) for each cylinder. Based on the
IGT signals, the igniter controls the primary ignition signals (IGC) for all ignition coils. At the same time, the
igniter also sends an ignition confirmation signal (IGF) as a fail–safe measure to the ECM.
DTC No.
DTC Detection Condition
Trouble Area
P0351
Condition (a) is repeated 3 times consecutively during 6 con-
secutively IGT signals while engine is running:
(a) IGF signal is not input to ECM for 2 or more ignitions
Ignition system
Open or short in IGF and IGT circuit from igniter to ECM
Igniter
Ignition coil
ECM
DIA9K–02
A18392
ECM
5 V
IGT1
LG–R
To
Tachometer
W–B
9
B–L
I3
Ignition Coil
10
Igniter
B–R
IGT2
IGT3
IGF
B–W
B–Y
7
6
5
4
8
2
1
3
Spark
Plug
B–R
G
E7
11