Engine Controls - Self-Diagnostics: Other Mercury Villager II

Malfunction Indicator Light

The Malfunction Indicator Light (MIL) is located on instrument panel and is labeled SERVICE ENGINE SOON or CHECK ENGINE. The MIL will illuminate if the PCM detects a failure of an OBD-II emission related component. When this occurs, a Diagnostic Trouble Code (DTC) will be set in PCM memory.

When PCM detects an emission related DTC during first drive cycle, DTC and engine data are stored in freeze frame memory. MIL light is illuminated only when PCM detects the same emission related DTC after it occurs in 2 consecutive trips. After MIL is illuminated, it will only turn off after PCM detects 3 trips without any faults occurring. One exception is if a misfire malfunction is detected that may damage catalytic converter. In this case the MIL will illuminate or flash immediately and DTC will be set. Misfire malfunctions will stay in Keep-Alive Memory (KAM) for 80 warm-up cycles. DTCs that would cause vehicle emissions to exceed established limits are capable of illuminating MIL during first trip. These include misfire, catalyst, and closed loop control DTCs. To turn MIL off after a repair, a PCM reset command from the scan tool must be sent, or 3 consecutive drive cycles must be completed without any detected malfunction.

On-Board Diagnostics

Powertrain Control Module (PCM) monitors several different engine control system circuits. If a malfunction occurs, PCM will record a Diagnostic Trouble Code (DTC) the next time engine is started and the same malfunction is detected.

PCM will erase a DTC when malfunction is not detected during 40 run/stop cycles of engine. PCM will erase a DTC for a misfire or fuel trim malfunction when no malfunction is detected for 80 run/stop cycles of engine with engine speed, coolant temperature, or other parameters similar to when malfunction first occurred.

When a DTC is stored, PCM will also record and store engine operating conditions when malfunction occurred. This information is referred to as freeze frame data. Freeze frame data will be stored in PCM memory until cleared, with the exception of the occurrence of an engine misfire or fuel trim malfunction. When a misfire of fuel trim fault occurs, freeze frame data will be updated with the most current information regarding these failures.

Freeze frame data recorded is

1. Engine coolant temperature.
2. Engine speed.
3. Vehicle speed.
4. Long term fuel compensation (long term fuel trim - displayed as percent).
5. Short term fuel compensation (short term fuel trim - displayed as percent).
6. Fuel control condition: Open or closed loop. Malfunction of rear O2S.
7. Calculated load value (displayed as percent).
8. Diagnostic Trouble Code (DTC) during data recording.

Hard Faults

Hard faults cause Malfunction Indicator Light (MIL) to illuminate and remain on until the malfunction is repaired. If light comes on and remains on or flashes during vehicle operation, cause of malfunction must be determined. Retrieve all DTCs. Refer to DIAGNOSTIC TEST MODE under QUICK TEST. If a sensor fails, PCM will use a substitute value in its calculations to continue engine operation. In this condition, vehicle is functional, but driveability will be affected.

Intermittent Faults

Intermittent faults may cause Malfunction Indicator Light (MIL) to flicker or illuminate and go out after the intermittent fault goes away. However, the corresponding Diagnostic Trouble Code (DTC) will be retained in PCM memory. If related malfunction does not reoccur within a certain time frame, related DTC will be erased from PCM memory. Intermittent faults may be caused by sensor, connector or wiring problems. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - VILLAGER article.

EQUIPMENT HOOKUP

Note. Some tests instruct the hookup of equipment to the fuse panel diagnostic connector. (Scheme 41) The diagnostic connector provides access to non-OBD-II functions. This connector is not generally used during normal engine diagnostic procedures.

Note. After performing equipment hookup, follow quick test procedure. See QUICK TEST .

1. Turn ignition off. Insert proper EPROM memory card into NGS tester. Attach OBD-II (16-pin) data cable to NGS tester.
2. Connect OBD-II data cable to OBD-II data link connector located under left side of instrument panel. (Scheme 41) Plug power cable into cigarette lighter. Turn ignition on. If serial communication is okay, go to «QUICK TEST»(ref-2846-S22894655392000041300000). If a serial communication error exists, see «COMMUNICATION ERROR»(ref-2846-S30700312252000041300000).

Scheme 40

Scheme 41

COMMUNICATION ERROR

If scan tool will not communicate with PCM (no response on scan tool) or will not respond to a particular request, a communication error exists. A communication error could be caused by the following

1. Operator Error
2. Vehicle Wiring
3. Dlc Terminals Damaged
4. Pcm Malfunction
5. Low Battery Voltage

Scan tool may display a 2-digit code indicating communication status. These codes are communication status codes, not DTCs. Some status codes indicate normal communication function. See COMMUNICATION CODES table. If scan tool displays a system okay code (Code 62) after performing QUICK TEST, go to TROUBLE SHOOTING - NO CODES - VILLAGER article for symptom diagnosis. If scan tool indicates a communication error (e.g., Code 10), go to TEST QA under SYSTEM TESTS for diagnostic procedure.

COMMUNICATION CODES

CLEARING CODES

Trip

Trip is defined as key on, key off event in which PCM detects a coolant temperature greater than 158°F (70°C) and changes to greater than 68°F (20°C) after starting engine, and engine speed is greater than 400 RPM. When PCM detects an emission related DTC(s), it uses the trip information to decide whether to illuminate the MIL.

OBD-II System Readiness Tests

In some areas of the country, it may become a legal requirement to pass an Inspection/Maintenance (I/M) test of the OBD-II system. Before I/M testing can proceed, all of the System Readiness Tests (SRT) must show a YES status on scan tool. Follow scan tool manufacturer's instructions.

During the mixed city and highway driving involved in the OBD-II drive cycle, the diagnostic test will test certain parts of the OBD-II software and hardware used to control vehicle emissions. Some tests will run to completion and will indicate a YES or NO, others such as misfire or fuel injection system test, will run continuously. See SRT STATUS table.

SRT STATUS

OBD-II Drive Cycle

Note. DTC will set when a fault is present in the system. Not all DTCs will illuminate MIL. Anytime a DTC is set or a repair is made and DTCs are cleared from PCM memory, the I/M ready monitors will reset to NO. To reset I/M monitors to a ready status, OBD-II drive cycle must be performed. Go to step 1 .

Note. PCM must see a change of at least 72°F (35°C) in ECT from the time engine is started until it reaches normal operating temperature of 158°F (70°C) before proceeding with drive modes of OBD-II drive cycle.

1. Warm engine to normal operating temperature of 158°F (70°C). Operate engine at idle for 2 minutes.
2. Accelerate at a steady rate (1/4-1/2 throttle) until vehicle reaches 55 MPH. Release accelerator pedal for at least 10 seconds. Allow vehicle speed to drop and then quickly depress accelerator to increase speed to 53-60 MPH. Drive at a steady speed of 53-60 MPH for 5 minutes.
3. Stop vehicle.
4. Accelerate vehicle at a steady rate until speed reaches 30-35 MPH. Drive at this speed for 20 seconds, the stop vehicle. Repeat steps 3 and 4 at least 3 times.
5. Accelerate smoothly until vehicle speed reaches 50-55 MPH and drive at this speed for about 3 minutes.
6. Stop vehicle and turn engine off for at least 5 seconds.
7. Repeat steps all the previous steps at least one more time. If a step is interrupted, repeat the preceding step.

Drive cycle pattern "C" monitors catalyst and other components. Using New Generation Star (NGS) tester or generic OBD-II scan tool, monitor TP PID. Steadily accelerate to 30-35 MPH. Ensure TP voltage is .8-1.2 volts throughout acceleration portion of test. Maintain 30-35 MPH for 20 seconds. Repeat 3 times. Accelerate smoothly to 50-55 MPH. Maintain this speed for 3 minutes. If a step is interrupted repeat preceding step.

Ford Specific (Non-Generic) OBD-II PIDs

Turn ignition off. Ensure test equipment is properly attached. Program scan tool using the following steps

1. Select vehicle and engine selection menu.
2. Select year, engine, model and any additional information requested by scan tool.
3. Select DIAGNOSTIC DATA LINK.
4. Select PCM - POWERTRAIN CTRL MODULE.
5. Select PID DATA MONITOR AND RECORD.
6. Turn ignition on or start engine and allow to idle.
7. Follow operating instructions from scan tool menu.
8. Select PIDs and press START.

Generic OBD-II PIDs

If a generic OBD-II scan tester is used it may require PID number to be entered. See GENERIC PID DEFINITION table. Turn ignition off. Ensure test equipment is properly attached. Program scan tool using the following steps

1. Select vehicle and engine selection menu (optional).
2. Select year, engine, model and any additional information requested by scan tool (optional).
3. Select GENERIC OBD-II OPTIONS. Press CONT button if monitors are not complete.
4. Select PID/DATA MONITOR.
5. Turn ignition on or start engine and allow to idle.
6. Follow operating instructions from scan tool menu.
7. Select PIDs and press START.

GENERIC PID DEFINITION

FREEZE FRAME DATA MODE

This mode allows access to data values captured during a malfunction that caused a DTC to set. These values are immediately stored in continuous memory when an emission related fault occurs. This provides a snapshot of conditions present when fault occurred. Freeze frame data will be stored until PCM memory is erased. Misfire fault data may override less important fault data.

To access FREEZE FRAME DATA MODE, turn ignition off. Ensure test equipment is properly attached. Program scan tool using the following steps

1. Select year, engine, model and any additional information requested by scan tool (optional).
2. Follow operating instructions from scan tool menu.
3. Select DIAGNOSTIC FUNCTIONS. Press CONT button if OBD-II System Readiness Tests (SRT) are not complete.
4. Turn ignition on.
5. Select FREEZE FRAME PID REQUEST.

SUMMARY

If no DTC is present but driveability problem(s) still exist, proceed to TROUBLE SHOOTING - NO CODES - VILLAGER article for symptom diagnosis or intermittent diagnostic procedure.

HOW TO USE TESTS

Note. For PCM connector terminal identification see scheme 3

1. Ensure all non-engine control related faults found while performing basic diagnostic procedures in BASIC DIAGNOSTIC PROCEDURES article have been corrected. DO NOT perform any test unless instructed by QUICK TEST or another test step. Follow each test step in order until fault is found. DO NOT replace any part unless directed to do so. When more than one code is retrieved, start with first code displayed.
2. Circuit tests ensure electrical circuits are okay before sensors or other components are replaced. Always test circuits for continuity between sensor and PCM. Test all circuits for short to power, opens or short to ground. Voltage Reference (VREF) and Voltage Power (VPWR) circuits should be tested with ignition on or as specified in tests.
3. DO NOT make voltage or resistance measurement by probing PCM connector, as harness and connector are easily damaged. DO NOT connect any test light unless specified in testing procedure. All measurements are made by probing rear of connector (wiring harness side) unless instructed otherwise. Isolate both ends of a circuit and turn ignition off when checking for shorts or continuity, unless instructed otherwise.
4. Disconnect solenoids and switches from harness before measuring continuity and resistance or applying voltage. After each repair, check all component connections and repeat «QUICK TEST»(ref-2846-S22894655392000041300000) .
5. An open is defined as a resistance reading of more than 5 ohms. However, this specification may be too high for some items. If resistance approaches 5 ohms, always clean suspect connector and coat it with protective dielectric silicone grease. A short is defined as a resistance reading of less than 10 k/ohms to ground, unless stated otherwise in test.