0585174 JOHNSON SENDING UNIT

Illustration 1 g01331438
Schematic of the analog throttle position sensor (31 Pin MIC)
Illustration 2 g01331437
Schematic of the analog throttle position sensor (70 Pin MIC)
Illustration 3 g01625095
ECM pin locations
(18) Throttle 2 Position
(25) Throttle 1 Position
(44) Sensor Common
(45) +5 Volt Supply Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Check the connectors and wiring for the following problems: damage, abrasion, corrosion and incorrect attachment.
Refer to Troubleshooting, "Electrical Connectors - Inspect".
Perform a 45 N (10 lb) pull test on each of the wires in the harness that are associated with the throttle position sensor. Check the wire connectors at the ECM, at the MIC, and at the throttle assembly.
P1:18 Throttle No 2
P1:25 Throttle No 1
P1:44 Sensor common
P1:45 +5V DC sensor supply
Check the ECM connector (Allen head screw) for the proper torque of 6.0 N m (55 lb in). Expected Result:The connectors and wiring should be free of the following faults: damage, abrasion, corrosion and incorrect attachment.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the connectors or wiring and/or replace the connectors or wiring.Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair has eliminated the fault.STOPTest Step 2. Check for active Diagnostic Codes
Turn the keyswitch to the ON position.
Use the electronic service tool to clear any logged diagnostic codes. Expected Result:RESULT 1 The electronic service tool displays the following active diagnostic codes:
91-02 Throttle Position Sensor erratic, intermittent, or incorrect
774-02 Secondary Throttle Position Sensor erratic, intermittent, or incorrectRESULT 2 The electronic service tool displays the following active diagnostic codes:
91-03 Throttle Position Sensor voltage above normal
91-04 Throttle Position Sensor voltage below normal
774-03 Secondary Throttle Position Sensor voltage above normal
774-04 Secondary Throttle Position Sensor voltage below normalRESULT 3 No active diagnostic codes are displayed on the electronic service tool.Results:
Result 1 - Repair: Refer to Troubleshooting, "Idle Validation Circuit Test".STOP
Result 2 - Proceed to Test Step 3.
Result 3 - Proceed to Test Step 4.Test Step 3. Check the Throttle Position Sensor with the Electronic Service Tool
Connect the electronic service tool to the diagnostic connector.
Turn the keyswitch to the ON position. Do not start the engine.
Monitor the raw throttle position reading on the electronic service tool.
Depress the throttle and release the throttle. Expected Result:The raw output should increase when the throttle pedal is depressed.The raw output should be between 15 percent and 27 percent at the low idle position. The output should be between 80 percent and 87 percent at the high idle position.Results:
OK - The throttle position sensor is operating correctly. Proceed to Test Step 5.
Not OK - The ECM is not receiving the correct signal from the TPS. Proceed to Test Step 4.Test Step 4. Check the Status of the Throttle Selection Switch with the Electronic Service Tool
Turn the keyswitch to the ON position.
Use the electronic service tool to check the status of the throttle selection switch (if equipped). Expected Result:If the throttle selection switch status is shown in the OFF position, then the throttle 1 has control of the engine speed.If the throttle selection switch status is shown in the ON position then the throttle 2 has control of the engine speed. The throttle can be overridden by use of the CAN B (SAE J1939) data link or the set speed control.Results:
OK - The throttle position switch is operating correctly.Repair: There may be an intermittent fault. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - The wrong throttle is selected. Change to the other throttle. There may be a fault with the input from the selector switch.Repair: Check the connections between the throttle selection switch and P1:10 and P1:37. Refer to Troubleshooting, "Electrical Connectors – Inspect".STOPTest Step 5. Check the Voltage at the Throttle Position Sensor
Illustration 4 g01331442
Connector for the throttle position sensor
(A) +5 Volt Supply
(B) Sensor Common
(C) Throttle Position Signal
Turn the keyswitch to the OFF position.
Disconnect the harness connector from the suspect TPS.
Turn the keyswitch to the ON position. Note: For the following tests, refer to Illustration 4.
Use a multimeter to measure the voltages at the harness connector, between the following terminals:
Terminal A to terminal B
Terminal B to terminal C
Terminal A to terminal CExpected Result:The voltages from the TPS should give the following readings:
Terminal A to terminal B = 5.0 Volts DC
Terminal B to terminal C = 10.25 Volts DC
Terminal A to terminal C = 5.25 Volts DCResults:
OK - The voltages from the TPS are within limits. There is a fault in the sensor.Repair: Replace the throttle position sensor, as follows:
Temporarily connect another TPS.
Use the electronic service tool to check if the diagnostic codes are still active