3T1-04302-0 Tohatsu FUEL FEED PUMP

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The following background information is related to this procedure:The tachometer circuit consists of the tachometer that is connected to the ECM through connector J1/P1 and through associated wiring. The ECM engine speed signal is provided by the engine speed/timing sensor. The ECM converts the signal from the engine speed/timing sensor into engine rpm in pulses per revolution before the ECM sends a signal to the tachometer. The selection of the pulses per revolution for the tachometer is done through the "Tachometer Calibration" parameter.The ECM tachometer signal is programmable from 12.0 to 500.0 pulses per revolution in 0.1 increments. The tachometer must be calibrated identically to this value for proper operation.The most likely source of a tachometer circuit problem is the vehicle wiring. The second most likely source of a tachometer circuit problem is the tachometer and the least likely source of a tachometer circuit problem is the ECM.Note: A tachometer may also be driven by the SAE J1587 data link or the J1939 data link. If the engine ECM communicates with the electronic service tool and the instrument cluster uses the signal from a data link, the problem is in one of two locations. Either the problem is in the wiring from the ECM to the dash, or the problem is in the dash.Note: Do not confuse a problem with the tachometer circuit with a problem that is associated with the engine speed/timing sensors. If a problem is suspected with the engine speed/timing sensors, refer to Troubleshooting, "Engine Speed/Timing Sensor Circuit - Test". Any problem that is associated with the engine speed/timing sensor will be apparent because of engine operation with a diagnostic code that is present. There are no diagnostic codes that are associated with the tachometer circuit.
Illustration 2 g01073861
Schematic No. 1 for tachometer
Illustration 3 g01073862
Schematic No. 2 for tachometer
Illustration 4 g01073867
ECM pin locationsTest Step 1. Use Caterpillar Electronic Technician (ET) to Check the ECM Tachometer Signal
Connect the Cat ET at the data link connector.
Turn the keyswitch to the ON position.
Access the "Tachometer Circuit Test". Access the following display screens in order:
"Diagnostics"
"Diagnostic Tests"
"Special Test"
While the dash tachometer is being monitored, begin the test.Expected Result:RESULT 1 The dash tachometer indicates approximately 1500 150 rpm and the dash tachometer is stable.RESULT 2 The tachometer does not indicate an engine rpm or the tachometer is erratic.RESULT 3 The tachometer rpm is stable but the tachometer does not indicate an engine speed that is within 50 rpm of 1500 rpm.Results:
Result 1 - The ECM and the tachometer are OK.STOP
Result 2 - The engine rpm is not indicated or the engine rpm is erratic. Proceed to Test Step 2.
Result 3 - The engine rpm is not within 50 rpm of 1500 rpm. Proceed to Test Step 6.Test Step 2. Determine the Type of Connection for the Tachometer Circuit
Determine if the wiring for the tachometer is wired directly to the ECM or through the J1939 or J1587 data link.Expected Result:The tachometer is wired directly to the ECM.Results:
OK - The tachometer is wired directly to the ECM. Proceed to Test Step 3.
J1939 data link - The tachometer is wired through the J1939 data link.Repair: Refer to Troubleshooting, "Powertrain Data Link Circuit - Test".STOP
J1587 data link - The tachometer is wired through the J1587 data link.Repair: Refer to Troubleshooting, "ATA (SAE J1587 / J1708) Data Link Circuit - Test".STOPTest Step 3. Inspect the Electrical Connectors and the Wiring
Thoroughly inspect the J1/P1 ECM connector, the firewall bulkhead connector, and the terminals for the tachometer in the connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the terminals for the tachometer:
P1-11
P1-17
Check the allen head screws for each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasion and for pinch points from the battery to the ECM.Expected Result:All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - Proceed to Test Step 4.
Not OK - Repair: Perform the following repair:
Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.
Verify that the repair eliminates the problem.STOPTest Step 4. Check the ECM Connection to the Tachometer
Inspect the J1/P1 ECM connector. Verify that the connections are present at P1-11 (tachometer-) and at P1-17 (tachometer+).Note: Some of the tachometers require only one signal line to be connected. Either of the ECM terminals can be used for this type of tachometer. The other wire should be left disconnected. If both wires are connected, and one indicates an open circuit, repair this line.Expected Result:Wires are connected to the ECM terminals for the tachometer, P1-11 (Tachometer-) and/or P1-17 (Tachometer+).Results:
OK - The ECM is providing the signal for the tachometer. Proceed to Test Step 5.
Not OK - The ECM is not connected in order to supply the signal to the tachometer.Repair: Send the vehicle to the OEM dealer in order to repair the tachometer circuit.STOPTest Step 5. Check the Tachometer Signal at the ECM Note: Performing certain steps within this procedure requires the use of a multimeter that is capable of measuring a PWM duty cycle.
Disconnect the J1/P1 ECM connector.
Connect a 40-pin breakout T between the J1 and P1 ECM connector .
Fabricate two jumper wires that are long enough to create a test circuit across the connector for the breakout T. Crimp connector pins to one end of each wire.
Insert one of the jumper wires into terminal locations terminal 11 (tachometer-) of the breakout T and insert the other jumper wire into terminal 17 (tachometer+) of the breakout T.Refer to Illustration 4.
Access the "Tachometer Circuit Test". Access the following display screens in order:
"Diagnostics"
"Diagnostic Tests"
"Special Test"
Attach multimeter leads to the loose ends of the jumper wires that are used to create the test circuit.
While the "Tachometer