Test Procedure
- B1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS)
Is DTC P0562, P0563, P0685, P0689, or P0690 present?
Yes No For DTCs P0562 or P0563, GO to B2.
For DTCs P0685 or P0690, GO to B8.
For DTC P0689, GO to B11.GO to B2. - B2 CHECK THE B+ AND IGN START/RUN VOLTAGE TO PCM POWER RELAY
- Ignition OFF.
- PCM Power Relay connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) PCM Power Relay Connector, Harness Side (-) B+ Ground IGN START/RUN Ground
Are the voltages greater than 10 V?
Yes No For Crown Victoria,
Grand Marquis,
Ranger, and
Town Car, GO to B6.
For all others, GO to B3.REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - B3 CHECK THE PCMRC CIRCUIT FOR AN OPEN IN THE HARNESS
- Ignition OFF.
- PCM connector disconnected.
- Measure the resistance between:
(+) PCM Power Relay Connector, Harness Side (-) PCM Connector, Harness Side PCMRC PCMRC
Is the resistance less than 5 ohms?
Yes No GO to B4. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - B4 CHECK THE PCMRC CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) PCM Connector, Harness Side (-) PCMRC Ground
Is any voltage present?
Yes No REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test. GO to B5. - B5 CHECK THE ISP-R VOLTAGE AT THE PCM HARNESS CONNECTOR
- Ignition OFF.
- PCM Power Relay connector connected.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) PCM Connector, Harness Side (-) ISP-R Ground
Is the voltage greater than 10 V?
Yes No GO to B7. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - B6 CHECK THE PCM POWER RELAY GROUND CIRCUIT FOR AN OPEN
- Measure the voltage between:
(+) PCM Power Relay Connector, Harness Side (-) PCM Power Relay Connector, Harness Side B+ GND
Is the voltage greater than 10 V?
Yes No GO to B7. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - Measure the voltage between:
- B7 CHECK FOR AN OPEN VPWR CIRCUIT BETWEEN THE PCM AND POWER RELAY
- Ignition OFF.
- PCM connector disconnected.
- Measure the resistance between:
(+) PCM Power Relay Connector, Harness Side (-) PCM Connector, Harness Side VPWR VPWR
Is the resistance less than 5 ohms?
Yes No INSTALL a new PCM Power relay.
CLEAR the DTCs. REPEAT the self-test.REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - B8 DTCS P0685 OR P0690: CHECK THE PCMRC CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS
- Ignition OFF.
- PCM Power Relay connector disconnected.
- PCM connector disconnected.
- Measure the resistance between:
(+) PCM Connector, Harness Side (-) PCMRC Ground
Is the resistance greater than 10K ohms?
Yes No GO to B9. REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test. - B9 CHECK THE ISP-R CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS
Is any voltage present?
Yes No REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test. GO to B10. - B10 CHECK THE INJPWRM CIRCUIT FOR AN OPEN IN THE HARNESS
- INJ connector disconnected.
- Measure the resistance between:
(+) PCM Connector, Harness Side (-) INJ Connector, Harness Side INJPWRM VPWR
Is the resistance less than 5 ohms?
Yes No GO to B12. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - B11 DTC P0689: CHECK THE ISP-R VOLTAGE AT THE PCM HARNESS CONNECTOR
- Ignition OFF.
- PCM connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
Is the voltage greater than 10 V?
(+) PCM Connector, Harness Side (-) ISP-R Ground Yes No GO to B12. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - B12 CHECK FOR CORRECT PCM OPERATION
- Ignition OFF.
- 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) , Programming the VID Block for a Replacement PCM. The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.