Diagnostic Procedure
WARNING: This page is about a different car, the 2005 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.
DIAGNOSTIC PROCEDURES - CHECKING THE SPEED CONTROL OPERATION
| TEST | ACTION | APPLICABILITY |
|---|---|---|
| 1 | Turn the ignition on. With the DRBIII®, read the ECM DTCs. Are there any ECM DTCs present? Yes --> Refer to the ECM DTC. Perform SPEED CONTROL VERIFICATION - VER-4 . No --> Go To 2 |
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| 2 | Start the engine. With the DRBIII® in Sensors, read the S/C Switch #1 volts. Observe the cruise switch volts on the DRBIII® while pressing and holding each cruise button separately.
NOTE:
Pressing each cruise button should result in the following voltages: ON/OFF 0.78v - 0.98, SET 3.26 - 3.46v, RESUME/ACCEL 3.93 - 4.13v, CANCEL 1.67 - 1.87v, COAST 2.64 - 2.84v, No Button Pressed 4.44 - 4.64v With the DRBIII®, read the S/C Switch #2 volts. Observe the cruise switch volts on the DRBIII® while pressing and holding each cruise button separately.
NOTE:
Pressing each cruise button should result in the following voltages: ON/OFF 3.62 - 3.82v, SET 1.25 - 1.45v, RESUME/ACCEL 2.13 - 2.33v, CANCEL 2.93 - 3.13v, COAST 0.78 - 0.98v, No Button Pressed 4.44 - 4.64v Does each switch provide the correct voltage? Yes --> Go To 3 No --> Check S/C Switch signal and Ground circuits. If OK., replace the S/C Switches. Perform SPEED CONTROL VERIFICATION - VER-4 . |
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| 3 |
NOTE:
Prior to testing the speed control operation, ensure the Learn Speed Control feature has been performed on the ECM. Test drive the vehicle above 60 km/h (35 MPH).Attempt to Set the Speed Control.Does the Speed Control function properly?Yes --> Test Complete.No --> Go To 4 |
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| 4 | Turn the ignition on. With the DRBIII® in Sensors, read Vehicle Speed. Have an assistant drive the vehicle while you are observing the Vehicle Speed on the DRBIII®. While observing vehicle speed on the DRBIII®, note any rapid changes (signal dropouts) in the reading that do not correspond with actual vehicle speed. Is the DRBIII® displaying an accurate vehicle speed? Yes --> Go To 5 No --> Refer to appropriate test for problems related to the Vehicle Speed Sensor. Perform SPEED CONTROL VERIFICATION - VER-4 . |
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| 5 | Turn the ignition on. With the DRBIII® in Inputs/Outputs, read the Primary and Secondary brake switch states while pressing and releasing the Brake Pedal several times. Did the DRBIII® indicate the correct brake pedal state when pressing and releasing the Brake Pedal? Yes --> Go To 6 No --> Refer to appropriate test for problems related to Brake Switch Signal. Perform SPEED CONTROL VERIFICATION - VER-4 . |
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| 6 |
WARNING:
WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING. Refer to any Technical Service Bulletins (TSB) that may apply.Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.Were any of the above conditions present?Yes --> Repair as necessary.Perform SPEED CONTROL VERIFICATION - VER-4 .No --> Replace and program the Engine Control Module in accordance with the Service Information.Perform SPEED CONTROL VERIFICATION - VER-4 . |
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