Engine Controls - Tests W/codes - 2.5L: Other Chrysler Cirrus I

Malfunction Indicator Light (MIL)

When ignition is first turned on, MIL should come on to verify bulb and circuit operation, and then go off. The MIL is located on instrument panel.

The Powertrain Control Module (PCM) monitors several different engine control system circuits. If PCM detects a malfunction on a monitored circuit often enough to indicate a problem, a Diagnostic Trouble Code (DTC) will be stored in PCM memory. If malfunction is emission related, PCM will illuminate MIL. MIL will stay on continuously if PCM has entered limp-in mode or identified a failed emission component. MIL will remain on until DTC is erased.

MIL will either flash or remain on steady if PCM detects an active engine misfire. Excessive engine misfires result in increased catalyst temperature and cause an increase Hydrocarbon (HC) emissions. Severe misfires may cause catalyst damage.

PCM may reset (turn off) MIL if PCM does not detect the malfunction for 3 consecutive trips, except for misfire and fuel system monitors. For misfire and fuel system monitors, if PCM does not detect the malfunction while engine is operating within 375 RPM of and within 10 percent of load of operating condition when malfunction was first detected.

A trip is defined as the engine is started, an increase of 40°F (4°C) in engine coolant temperature exists after engine is started, and engine coolant temperature reaches at least 160°F (71°C). For additional information on engine misfire and fuel system monitor, see ON-BOARD DIAGNOSTICS.

Note. On-Board Diagnostics II (OBD II) is used.

On-Board Diagnostics

The Powertrain Control Module (PCM) monitors several different engine control system circuits. If PCM detects a malfunction on a monitored circuit often enough to indicate a problem, a Diagnostic Trouble Code (DTC) will be stored in PCM memory.

If DTC is for a non-emissions related system or component, and problem is repaired or does not reoccur, PCM cancels DTC after 40 consecutive trips. PCM will cancel DTC's which affect emissions (engine misfire and fuel system monitor) after 80 consecutive trips if malfunction does not reoccur.

Excessive engine misfires result in increased catalyst temperature and cause an increase Hydrocarbon (HC) emissions. Severe misfires may cause catalyst damage. PCM monitors for misfire during most engine operating conditions by observing crankshaft speed. If a misfire occurs, crankshaft speed will vary more than normal.

For fuel system monitor, PCM makes short term adjustments in injector pulse width based on O2S input. PCM uses programmed memory to act like a self calibration tool to compensate for engine specification variations, engine wear and sensor tolerances over useful life of engine. PCM monitors actual air/fuel ratio with O2S. PCM multiplies O2S (short term) with programmed (long term) adaptive memory, and compares sum with limit. PCM can determine if vehicle will pass an emissions test. If PCM cannot maintain optimum air/fuel ratio, MIL will be illuminated.

The PCM contains electronic circuit monitors that monitor fuel, vehicle emissions, engine and ignition system performance. Monitors do not indicate a specific component failure, but do indicate an implied failure within a specified system, and that the problem must be diagnosed. If any monitor detects a problem affecting vehicle emissions, a Diagnostic Trouble Code (DTC) will be stored in PCM and MIL will be illuminated. The following monitors are used

1. EGR Monitor
2. Engine Misfire Monitor
3. Fuel System Monitor
4. Oxygen Sensor Monitor
5. Oxygen Sensor Heater Monitor
6. Catalyst Monitor
7. EVAP System Leak Detection Monitor

If PCM does not detect the malfunction for 3 consecutive trips, except for misfire and fuel system monitors. For misfire and fuel system monitors, if PCM does not detect the malfunction while engine is operating within 375 RPM of and within 10 percent of load of operating condition when malfunction was first detected.

A trip is defined as the engine is started, an increase of 40°F (4°C) in engine coolant temperature exists after engine is started, and engine coolant temperature reaches at least 160°F (71°C).

The PCM also records and stores engine operating conditions when malfunction occurred. This information is referred to as freeze frame data. If malfunction is an engine misfire or fuel system rich or fuel system lean, freeze frame data will be updated with the most current information regarding these failures.

Freeze frame data recorded is

1. Fuel System Status
2. Load Value (Displayed As Percent)
3. Engine Coolant Temperature
4. Short Term Adaptive (Displayed As Percent)
5. Long Term Adaptive (Displayed As Percent)
6. Absolute MAP (Displayed As Percent)
7. Engine RPM
8. Vehicle Speed Sensor
9. Diagnostic Trouble Code (DTC) During Data Recording

DTCs may be retrieved for system diagnosis. See procedures under RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. System malfunctions are identified as either hard failures or intermittent failures.

Hard Failures

Hard failures cause MIL to illuminate and remain on until problem is repaired. If light comes on and remains on during vehicle operation, cause of malfunction must be determined by retrieving DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. If a sensor fails, PCM will use substitute value in its calculations to continue engine operation. In this condition, commonly known as limp-in mode, the vehicle runs but driveability will not be optimum.

Intermittent Failures

Intermittent failures may cause MIL to flicker or illuminate and go out after intermittent failure goes away. However, the corresponding diagnostic trouble code will be retained in PCM memory. If related failure does not reoccur within a certain time frame, related diagnostic trouble code will be erased from PCM memory. Intermittent failures may be caused by a sensor, connector or wiring related problems. See INTERMITTENTS in the TESTS W/O CODES - 2.5L article.

SERVICE PRECAUTIONS

Before proceeding with diagnosis, the following precautions must be followed

1. Ensure fuel pressure is released before removing fuel line or fittings, as fuel system is under pressure and may cause personal injury. See «FUEL PRESSURE RELEASE»(ref-24768-S25971143532001010500000) .
2. When using SELF-DIAGNOSTIC TESTS for diagnosis, DO NOT skip any steps, or incorrect diagnosis may result. Always perform indicated verification procedure after repairs are made.
3. When using a jumper wire, ensure either jumper wire or circuit is fuse-protected.
4. Before disconnecting connector from any control module, ensure ignition is off before removing connector.
5. When checking voltage or continuity at any control module, probe connector for control module from pin side. DO NOT backprobe connector or probe wires through the insulation.
6. DO NOT cause short circuits when performing electrical tests. This will set additional Diagnostic Trouble Codes (DTCs), making diagnosis of original problem more difficult.
7. Use specified test equipment when performing electrical tests.
8. When checking for spark, ensure coil wire is NOT more than 1/4" from engine ground. If coil wire is more than 1/4" from engine ground, damage to vehicle electronics and/or PCM may result.
9. DO NOT prolong testing of fuel injectors or engine may hydrostatically lock.

Using Malfunction Indicator Light (MIL)

1. Ensure battery is fully charged. Turn ignition on and note operation of MIL. The MIL is located on instrument panel. When ignition is first turned on, MIL should come on to verify bulb and circuit operation, and then go off. NOTE: If MIL does not come on and then go off, bulb circuit may be defective, or problem area may exist on CCD Bus between Powertrain Control Module (PCM) and instrument cluster. If problem exists with CCD Bus, this problem may be displayed when using scan tool to retrieve DTCs.
2. Turn ignition on, off, on, off and on within 5 seconds. Record 2-digit Diagnostic Trouble Codes (DTCs) as displayed by flashing MIL.
3. For example, DTC 24 will be displayed by 2 flashes, short pause, and then 4 flashes. A short pause will exist between first and second digits on DTC. If more than one DTC is stored, after first DTC is displayed, there will be a longer pause and then another stored DTC will be displayed.
4. Once all DTCs are recorded, proceed to retrieving DTCs using scan tool to ensure all DTCs are obtained. See USING SCAN TOOL.

Scheme 106

1. Ensure battery is fully charged. Turn ignition off. Connect scan tool to Data Link Connector (DLC). One connection required at 16-pin DLC. See DATA LINK CONNECTOR (DLC) table for connector location. (Scheme 106) DATA LINK CONNECTOR (DLC) LOCATION Application DLC Location Cirrus & Stratus 2.5L Above Driver's Kick Panel
2. Turn ignition on. Using scan tool manufacturer's instructions, record all DTCs displayed on scan tool. Using all DTCs obtained, proceed to «SELF-DIAGNOSTIC TESTS»(ref-24768-S31575563452001010500000). Once all repairs are made, ensure DTCs are cleared from PCM. See CLEARING DIAGNOSTIC TROUBLE CODES.

FUEL PRESSURE RELEASE

1. Turn ignition off. Slowly open fuel tank cap to release pressure in tank. Disconnect injector harness connector. Connect a jumper wire between injector connector (injector side) Dark Green/Orange wire and battery positive terminal.
2. Connect another jumper wire to injector connector (injector side) White/Light Blue wire. Momentarily ground jumper wire connected to White/Light Blue wire for no more than 5 seconds. Injector No. 1 will energize open, relieving some fuel pressure. Remove jumper wire from White/Light Blue wire.
3. Connect a jumper wire to injector connector (injector side) Yellow/White wire. Momentarily ground jumper wire connected to Yellow/White wire for no more than 5 seconds. Injector No. 3 will energize open, relieving some fuel pressure. Remove jumper wire from Yellow/White wire.
4. Connect another jumper wire to injector connector (injector side) Gray wire. Momentarily ground jumper wire connected to Gray wire for no more than 5 seconds. Injector No. 5 will energize open, relieving some fuel pressure. Remove jumper wire from Gray wire.
5. Remove jumper wire from Dark Green/Orange wire. Energizing 3 different fuel injectors should have relieved enough fuel pressure to safely open fuel system. Use caution when opening fuel system, some residual fuel pressure may be present.