Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Inspection and Verification
2006 Lincoln ZephyrSECTION Inspection and Verification
- Verify the customer concern.
- Visually inspect the following for obvious signs of mechanical or electrical damage.VISUAL INSPECTION CHART
Mechanical Electrical - Throttle body
- Battery junction box (BJB) fuse 44 (15A)
- Circuitry
- Speed control switch
- Clutch pedal speed control deactivator switch (manual transaxle)
- Speed control deactivator switch (part of the stoplamp switch)
- Stoplamp switch
- Powertrain control module (PCM)
- If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
- Verify the speedometer operates correctly without speed control by test driving the vehicle. If the speedometer does not operate correctly, refer to INSTRUMENT CLUSTER .
- Verify the stoplamps operate correctly with the ignition switch in the ON position. If the stoplamps do not operate correctly, refer to EXTERIOR LIGHTING .
- Verify the parking brake warning indicator is operating correctly. If the parking brake warning indicator does not operate correctly, refer to INSTRUMENT CLUSTER .
- If the cause is not visually evident, connect the diagnostic tool to the data link connector (DLC) and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
- Check that the program card is correctly installed.
- Check the connections to the vehicle.
- Check the ignition switch position.
- If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual.
- Carry out the diagnostic tool data link test. If the diagnostic tool responds with:
- CAN circuits fault; all electronic control units no response/not equipped, refer to MODULE COMMUNICATIONS NETWORK .
- No response/not equipped for PCM, refer to MODULE COMMUNICATIONS NETWORK .
- System passed, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs, and carry out the self-test diagnostics for the PCM.
- If the DTCs retrieved are related to the concern, go to the POWERTRAIN CONTROL MODULE (PCM) DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
- If no DTCs related to the concern are retrieved, GO to SYMPTOM CHART .
POWERTRAIN CONTROL MODULE (PCM) DIAGNOSTIC TROUBLE CODE (DTC) INDEX
| DTCs | Description | Source | Action |
|---|---|---|---|
| P0500 | Vehicle Speed Error | PCM | REFER to the INTRODUCTION - GASOLINE article. |
| P0579 | Cruise Control Multifunction Input A Circuit Range/Performance | PCM | GO to PINPOINT TEST C . |
| P0581 | Cruise Control Multifunction Circuit High | PCM | GO to PINPOINT TEST C . |
| PO833 | Clutch Pedal Switch B Circuit | PCM | GO to PINPOINT TEST D . |
| P1572 | Brake Pedal Switch Circuit | PCM | GO to PINPOINT TEST B . |
| P1703 | Brake Switch Out of Self-Test Range | PCM | GO to PINPOINT TEST B . |
| All other DTCs | - | PCM | REFER to the INTRODUCTION - GASOLINE article to continue diagnosis. |
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.