921503-6512 Tohatsu SCREW

Illustration 1 g01245089
Diagram of components
C15 and C18 Engines
Illustration 2 g01192490
Left side engine view (typical example)
(1) Engine coolant temperature sensor
(2) Secondary engine speed/timing sensor
(3) Intake manifold pressure sensor
(4) Injector valve cover entry connector
(5) Intake manifold air temperature sensor
(6) Differential pressure switch (fuel)
(7) Fuel pressure sensor
(8) Fuel temperature sensor
(9) Primary engine speed/timing sensor
(10) Timing calibration port
(11) Atmospheric pressure sensor
(12) Engine oil pressure sensor
(13) Timing calibration probe connector
(14) Engine Control Module (ECM)
(15) J2/P2 ECM connector
(16) J1 ECM connector
Illustration 3 g01193730
Location of the throttle position sensor (typical example)
Illustration 4 g01195919
Location of the turbocharger inlet pressure sensor (typical example)
Engine Wiring Information
The wiring schematics are revised periodically. The wiring schematics will change as updates are made to the machine harness. For the most current information, always check the revision number of the schematic. Use the schematic with the latest revision number.Harness Wire Identification
Caterpillar identifies all wires with eleven solid colors. The circuit number is stamped on the wire at a 25 mm (1 inch) spacing. Table 1 lists the wire colors and the color codes.
Table 1
Color Codes for the Harness Wire
Color Code Color Color Code Color
BK Black GN Green
BR Brown BU Blue
RD Red PU Purple
OR Orange GY Gray
YL Yellow WH White
PK Pink For example, a wire identification of A701-GY(Grey) on the schematic would signify a gray wire with the circuit number A701. A701-GY(Grey) identifies the power circuit for the No. 1 Injector solenoid.Another wire identification on the schematic is the size of the wire. The size of the wire will follow the wire color. Wire size or gauge is referred to as AWG (Americal Wire Gauge). AWG is a description of the diameter of the wire.For example, a code of 150-OR(Orange) on the schematic would indicate that the orange wire in circuit 150 is a 14 AWG wire.If the gauge of the wire is not listed, the wire is 16 AWG.Conversion of AWG Numbers to Metric Measurements
Table 2 shows the various AWG numbers that are used for the wires. The metric equivalent for the diameter of each AWG number are also shown.
Table 2
Metric Equivalents for AWG Numbers
AWG Number Diameter (mm) AWG Number Diameter (mm)
20 0.8 14 1.6
18 1.0 12 2.0
16 1.3 4 3.2 Welding on a Machine that is Equipped with an Electronic Control Module
Proper welding procedures are necessary in order to avoid damage to the engine's electronic control module, sensors, and associated components. The component that requires welding should be removed. When welding on a machine that is equipped with an ECM and removal of the component is not possible, the following procedure must be followed. This procedure provides the minimum amount of risk to the electronic components.
Do not ground the welder to electrical components such as the ECM or sensors. Improper grounding can cause damage to the drive train bearings, hydraulic components, electrical components, and other components.Clamp the ground cable from the welder to the component that will be welded. Place the clamp as close as possible to the weld. This will help reduce the possibility of damage.
Stop the engine. Turn the keyswitch to the OFF position.
Disconnect the negative battery cable from the battery. If a battery disconnect switch is installed, open the switch.
Illustration 5 g01143634
Service welding guide (typical diagram)
Connect the welding ground cable as close as possible to the area that will be welded. Components which may be damaged by welding include bearings, hydraulic components, and electrical/electronic components.
Protect the wiring harness from welding debris and from spatter.
Weld the materials by using standard welding methods.