3AC-10100-1 Tohatsu THROTTLE BODY ASSEMBLY

Illustration 1 g01390181
Schematic for a single engine configurationIn this configuration, a single engine can be controlled by two throttles. The secondary throttle is enabled by activation of a switch. This switch is wired to the engine synchronization input (No. 2).Dual Engine Configuration
Illustration 2 g01390182
Schematic for a dual engine configurationIn this configuration, the position of the synchronization switch determines the throttle input that is recognized by each engine. Table 1 lists the engine's response to each position of the switch.
Table 1
Engine Response to the Synchronization Switch    
Position of the Synchronization Switch    Engine Response    
Starboard     Both engines respond to the starboard throttle.    
None     Each engine responds to a separate throttle.    
Port     Both engines respond to the port throttle.    Multiple Engine Configuration Without a Dedicated Master Throttle
Illustration 3 g01390183
Multiple engine configuration with one throttle that is designated as a master throttleIn these configurations, one of the throttles has been designated as the master throttle. When the engine synchronization switch is not activated, each engine will respond to the appropriate throttle. When the engine synchronization switch is activated, all of the engines will respond to the master throttle. Three engines and three throttles are shown. As many as five engines and five throttles can be connected in this manner.Multiple Engine Configuration With a Dedicated Master Throttle
Illustration 4 g01390184
Multiple engine configuration with a separate throttle that is used for the master throttleIn this configuration, the application is equipped with a master throttle in addition to a separate throttle for each engine. When the engine synchronization switch is not activated, each engine will respond to the appropriate throttle. When the engine synchronization switch is activated, all of the engines will respond to the master throttle.Test Step 1. Verify that the Throttle Positions are Correct
Determine the application's configuration for engine synchronization. Identify the two throttles that are connected to the throttle inputs for the ECM.Note: The ECM will not transfer control between the throttles unless the throttle positions are within 50 rpm of each other.
Verify that the throttle positions are within 50 rpm of each other.Expected Result:The throttle positions are within 50 rpm of each other.Results:
OK - The throttle positions are within 50 rpm of each other. Proceed to Test Step 2.
Not OK - The throttle positions are not within 50 rpm of each other.Repair: Adjust the throttles until the throttle positions are within 50 rpm of each other. Try to synchronize the engines.If the engines become synchronized, the problem seems to be resolved at this time. If the engines do not become synchronized, proceed to Test Step 2.Test Step 2. Check the Configuration Parameters
Connect the Caterpillar Electronic Technician (ET) to the service tool connector.
Verify that the following configuration parameters are programmed correctly:
Number of Synchronized Engines Configuration
Engine Location
Secondary Throttle Enable StatusRefer to Troubleshooting, "Configuration Parameters" for additional information on these parameters.Expected Result:The configuration parameters are programmed correctly.Results:
OK - The configuration parameters are programmed correctly. Proceed to Test Step 3.
Not OK - The configuration parameters are not programmed correctly.Repair: Program the correct value for each parameter.Verify that the problem is resolved.STOPTest Step 3. Check for Diagnostic Codes for the Throttle Inputs
Check for the following diagnostic codes:
91-13 Throttle Position calibration required
1249-13 Secondary Throttle Position calibration requiredExpected Result:Neither diagnostic code is active or logged.Results:
OK - Neither diagnostic code is active or logged. Proceed to Test Step 4.
Not OK - At least one of the diagnostic codes is logged.Repair: Perform the following procedure:
Clear the logged codes.
Slowly move the suspect throttle throughout the entire range. Move the throttle several times. Look for the activation of the diagnostic code again.If the diagnostic code does not recur, attempt to synchronize the engines. If the engines become synchronized, the problem appears to be resolved.The original problem may have been caused by an intermittent problem in one of these components:
Throttle position sensor
Wiring for the throttle
An electrical connectorIf the diagnostic code recurs, there is a problem with the circuit for the throttle position sensor. Refer to Troubleshooting, "Speed Control - Test" for the troubleshooting procedure.STOP
Not OK - There is an active