Diagnostic Procedure
DIAGNOSTIC PROCEDURES - P0594-SPEED CONTROL SERVO POWER CIRCUIT
| TEST | ACTION | APPLICABILITY |
|---|---|---|
| 1 | Turn the ignition off. Disconnect the Speed Control Servo harness connector. Ignition on, engine not running.
NOTE:
It is necessary to PRESS and HOLD the Speed Control Switch in the ON position while checking for voltage. Using a 12-volt test light connected to ground, probe the (V30) S/C Brake Switch Output terminal in the Servo Harness connector. Does the test light illuminate brightly? Yes --> Refer to the INTERMITTENT CONDITION SYMPTOM . Perform POWERTRAIN VERIFICATION TEST VER - 5 . No --> Go To 2 |
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| 2 | Turn the ignition off. Disconnect the PCM harness connector. Disconnect the Brake Lamp Switch harness connector.
CAUTION:
DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS. Measure the resistance of the (V32) S/C Power Supply circuit from the Brake Lamp Switch harness connector to the appropriate terminal of special tool #8815. Is the resistance below 5.0 ohms? Yes --> Go To 3 No --> Repair the open/high resistance in the (V32) S/C Power Supply circuit between the PCM and Brake Switch. Perform POWERTRAIN VERIFICATION TEST VER - 5 . |
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| 3 | Turn the ignition off. Disconnect the PCM harness connector. Disconnect the Brake Switch harness connector. Measure the resistance between ground and the (V32) S/C Power Supply circuit in the Brake Switch harness connector. Is the resistance below 100 ohms? Yes --> Go To 4 No --> Repair the short to ground in the (V32) S/C Power Supply circuit. Perform POWERTRAIN VERIFICATION TEST VER - 5 . |
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| 4 | Turn the ignition off. Disconnect the Speed Control Servo harness connector. Disconnect the Brake Switch harness connector. Measure the resistance between ground and the (V30) S/C Brake Switch Output circuit at the Speed Control Servo harness connector. Is the resistance below 100 ohms? Yes --> Repair the short to ground in the (V30) S/C Brake Switch Output circuit. Perform POWERTRAIN VERIFICATION TEST VER - 5 . No --> Go To 5 |
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| 5 | Turn the ignition off. Disconnect the S/C Servo harness connector. Disconnect the Brake Switch harness connector. Measure the resistance of the (V30) S/C Brake Switch Output circuit from the Brake Switch harness connector to the S/C Servo harness connector. Is the resistance below 5.0 ohms? Yes --> Go To 6 No --> Repair the open/high resistance in the (V30) S/C Brake Switch Output circuit. Perform POWERTRAIN VERIFICATION TEST VER - 5 . |
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| 6 | Disconnect the Brake Lamp Switch harness connector. Ignition on, engine not running. Using a 12-volt test light connected to ground, probe the (V32) Speed Control Power Supply circuit in the Brake Lamp Switch harness connector.
NOTE:
It is necessary to HOLD the Cruise Control Switch in the ON position to get an accurate reading. Does the test light illuminate brightly? Yes --> Replace the Brake Lamp Switch. Perform POWERTRAIN VERIFICATION TEST VER - 5 . No --> Go To 7 |
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| 7 |
NOTE:
Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary. If there are no possible causes remaining, view repair.RepairReplace and program the Powertrain Control Module in accordance with the Service Information.Perform POWERTRAIN VERIFICATION TEST VER - 5 . |
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