Test Procedure
WARNING: This page does not describe the selected car, but rather 30 other vehicles, including the 2006 Mercury Mountaineer, 2006 Mercury Monterey, 2006 Mercury Montego, 2006 Mercury Milan, and 2006 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
- NB1 OBSERVE THE MIL
Is the MIL never on?
Yes No GO to NB4. GO to NB2. - NB2 MIL ALWAYS ON (NO DTCS PRESENT)
Does the vehicle start?
Yes No GO to NB3. The concern is elsewhere. RETURN to SYMPTOM CHARTS for further direction. - NB3 CHECK THE MIL CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS
- Key in OFF position.
- PCM connector disconnected.
- Measure the resistance between:
( + ) PCM Connector, Harness Side ( - ) Vehicle Battery MIL Negative terminal
Is the resistance greater than 10K ohms?
Yes No GO to NB7. REPAIR the circuit.
CLEAR the DTCs. REPEAT the self-test. - NB4 MIL NEVER ON
Does the vehicle start?
Yes No GO to NB5. The concern is elsewhere. RETURN to SYMPTOM CHARTS for further direction. - NB5 MIL HARNESS CHECK
- Key in OFF position.
- PCM connector disconnected.
- Key ON, engine OFF.
- Connect a 5 amp fused jumper wire between the following:
Point A PCM Connector, Harness Side Point B MIL Ground - Remove the jumper wire(s).
Does the MIL Illuminate when grounded?
Yes No GO to NB7. GO to NB6. - NB6 CHECK FOR AN OPEN MIL CIRCUIT BETWEEN THE PCM AND INSTRUMENT CLUSTER
- Key in OFF position.
- Disconnect the instrument cluster.
- Measure the resistance between:
( + ) PCM Connector, Harness Side ( - ) Instrument Cluster Connector, Harness Side MIL MIL
Is the resistance less than 5 ohms?
Yes No REFER to the appropriate INSTRUMENT CLUSTER article to diagnose the MIL and its circuitry. REPAIR the circuit.
VERIFY the repair by turning the key ON, engine OFF.
CLEAR the DTCs. REPEAT the self-test. - NB7 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Visually inspect for:
- pushed out pins
- corrosion
- Connect all the PCM connectors and make sure they seat correctly.
- Carry out the PCM self-test and verify the concern is still present.
Is the concern still present?
Yes No INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) . The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.