0325224 JOHNSON SEAL, Motor cover

Illustration 1 g01259212
Schematic No. 1 for the tachometer
Illustration 2 g01259219
Schematic No. 2 for the tachometerTest Step 1. Use Cat ET to Check the ECM Tachometer Signal
Connect Cat ET at the data link connector.
Remove the electrical power from the ECM.
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 rpm is not 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
Determine if the wiring for the tachometer is wired directly to the ECM or through the J1939 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, "CAN Data Link - Test".STOPTest Step 3. Inspect the Electrical Connectors and the Wiring
Illustration 3 g01186024
Location of the J1/P1 ECM connectors (typical left side engine view)
Thoroughly inspect the J1/P1 ECM connectors, the firewall bulkhead connector, and the terminals for the tachometer in the connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 4 g01259221
Terminal locations at the P1 ECM connector for the tachometer circuit (P1-38) Tachometer + (P1-39) Tachometer −
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.
Check the allen head screw 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 - The harness and connectors appear to be OK. Proceed to Test Step 4.
Not OK - There is a problem with the connectors and/or wiring.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 P1-39 Tachometer − and/or P1-38 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, P1-39 (Tachometer −) and/or P1- 38 (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 ECM Note: Performing certain steps within this procedure requires the use of a multimeter that is capable of measuring a PWM Duty Cycle.
Remove the electrical power from the ECM.
Disconnect the J1/P1 ECM connector.
Remove the wire in P1-38 Tachometer + from the ECM connector P1.
Remove the wire in P1-39 Tachometer − from the ECM connector P1.
Fabricate two jumper wires that are long enough to create a test circuit at the breakout T. Crimp connector pins to one end of each of the jumper wires.
Install a 208-0059 Adapter Cable As (70-PIN BREAKOUT) to the ECM vehicle harness connector J1/P1.
Insert one of the jumper wires into terminal location 39 (Tachometer −) of the breakout T and insert the other jumper wire into terminal location 38 (Tachometer +) of the breakout T.
Access the "Tachometer Circuit Test". Access the following display screens in order:
"Diagnostics"
"Diagnostic Tests"
"Special Test"
Attach the positive lead of the multimeter to the jumper wire from P1-38.
Attach the negative lead of the multimeter to the jumper wire from P1-39.
While the "Tachometer Circuit Test" is being run, observe the reading on the multimeter.
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