Engine Controls Self-Diagnostics - 4.7L & 5.7L: Other Dodge Pickup R1500

Monitored Circuits

The Powertrain Control Module (PCM) contains electronic circuit monitors that monitor fuel, vehicle emissions, engine and ignition system performance. Monitors use information from various sensor circuits for system monitoring. 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 set in PCM after 2 consecutive trips with the malfunction present. For additional information for trip definition, see TRIP DEFINITION . The following monitors are used.

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

The PCM will erase or clear DTCs once malfunction indicator light is turned off. For additional information for DTC erasure, see DIAGNOSTIC TROUBLE CODE PRIORITY & SELF-ERASURE .

Trip Definition

A trip has different meanings depending on what the circumstances are. If MIL is off, a trip is defined as when oxygen sensor monitor and catalyst monitor have been completed in the same drive cycle. When any emission related DTC is set, the MIL is turned on. When MIL is on, it takes 3 good trips to turn the MIL off. In this case it depends on what type of DTC is set to identify what a trip is.

If MIL is on and a DTC was set by fuel monitor or misfire monitor, the vehicle must be operated in SIMILAR CONDITIONS WINDOW for a specified amount of time to be considered a good trip. SIMILAR CONDITIONS WINDOW displays information about engine operation during a monitor. If a non-continuous OBD-II monitor such as: oxygen sensor monitor, catalyst monitor, purge flow monitor, leak detection pump monitor or oxygen sensor heater monitor fails twice in a row and turns on the MIL, re-running that monitor which previously failed on next engine start-up and passing the monitor is considered to be a good trip. If any other emission related DTC which is not an OBD-II monitor is set, a good trip is considered to be when oxygen sensor monitor or catalyst monitor have been completed, or 2 minutes of engine run times exists and oxygen sensor monitor and catalyst monitor have been stopped from running. Trips may be read on the scan tool. For additional information for trip displays on scan tool, see TRIP INDICATORS .

It can take up to 2 failures in a row to turn on the MIL. After MIL is turned on, it takes 3 good trips to turn the MIL off. After MIL is off, the PCM will erase or clear the DTC after 40 warm-up cycles. A warm-up cycle is defined as the engine is started, an increase of 40°F in engine coolant temperature exists after engine is started and engine coolant temperature reaches at least 160°F (71°C).

Trip Indicators

Trip indicators may be displayed on scan tool. A trip is essential for running the monitors and turning off the Malfunction Indicator Light (MIL). A trip is a set of vehicle operating conditions that must be met for a specified monitor to run. A trip begins with a cycle of ignition key. Trip indicators consist of good trip counters. Good trip counters are: specific good trip, fuel system good trip, misfire good trip and warm-up cycles.

On specific good trips, the term good trip has different meanings. If MIL is off, a trip is defined as when oxygen sensor monitor and catalyst monitor have been completed in the same drive cycle. If MIL is on and a Diagnostic Trouble Code (DTC) was set by fuel monitor or misfire monitor, the vehicle must be operated in the SIMILAR CONDITIONS WINDOW for a specified amount of time to be considered a good trip. SIMILAR CONDITIONS WINDOW displays information about engine operation during a monitor. If MIL is on and a DTC was set by task manager commanded once per trip monitor such as oxygen sensor monitor, catalyst monitor, purge flow monitor, leak detection pump monitor or oxygen sensor monitor, a good trip is when the monitor passed on next engine start-up. If MIL is on and any other emission related DTC which is not an OBD-II monitor is set, a good trip is considered to be when oxygen sensor monitor or catalyst monitor have been completed, or 2 minutes of engine run times exists and oxygen sensor monitor and catalyst monitor have been stopped from running.

On fuel system good trips, engine must be in closed loop, operating in SIMILAR CONDITIONS WINDOW and short term multiplied by long term must be less than threshold for a predetermined time. SIMILAR CONDITIONS WINDOW displays information about engine operation during a monitor. If all of these conditions exist, Powertrain Control Module (PCM) will count this as a good trip. Good trip must exist 3 times before PCM will shut off the MIL.

On misfire good trip, vehicle must be operated in the SIMILAR CONDITIONS WINDOW and engine must operate for 1000 revolutions without a misfire. If all of these conditions exist, PCM will count this as a good trip. Good trip must exist 3 times before PCM will shut off the MIL.

On warm-up cycles, once MIL has been turned off by good trip counter, PCM switches to warm-up counter which may be viewed on scan tool. Warm-up cycles are used to erase or clear DTC and freeze frame data. A warm-up cycle is defined as the engine is started, an increase of 40°F in engine coolant temperature exists after engine is started and engine coolant temperature reaches at least 160°F (71°C). After 40 warm-up cycles with no malfunction, PCM will erase or clear the DTC.

Non-Monitored Circuits

Powertrain Control Module (PCM) does not monitor all circuits, conditions and systems that could cause a malfunction or driveability problem. However, problems with these systems may cause PCM to store Diagnostic Trouble Codes (DTC) for other systems or components.

For example, a fuel pressure problem will not cause a DTC directly, but could cause a rich/lean condition or misfire. This could cause PCM to store an oxygen sensor or misfire DTC. The major non-monitored circuits are identified below.

1. Cylinder Compression
2. Excessive Oil Consumption
3. Exhaust System
4. Fuel Injector Mechanical Faults
5. Fuel Pressure
6. PCM Connector Engagement
7. PCM System Ground
8. Secondary Ignition System
9. Throttle Body Airflow
10. Vacuum Assist

Hard Failures

Hard failures cause Malfunction Indicator Light (MIL) to illuminate and remain on until problem is repaired. This means the defect is there every time the Powertrain Control Module (PCM) checks that circuit or function. If MIL comes on and remains on during vehicle operation, cause of malfunction must be determined by retrieving Diagnostic Trouble Codes (DTC). See RETRIEVING DIAGNOSTIC TROUBLE CODES . 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 malfunction indicator light to flicker or illuminate and go out after intermittent failure goes away. However, the corresponding Diagnostic Trouble Code (DTC) will be retained in Powertrain Control Module (PCM) memory. If related failure does not reoccur within a certain time frame, related DTC will be erased or cleared from PCM memory. Most intermittent failures are caused by a sensor, electrical connector or wiring related problems. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

SERVICE PRECAUTIONS

Before proceeding with system diagnosis, following precautions must be followed

1. Before performing any testing procedures, check for any related Technical Service Bulletins (TSB).
2. Ensure fuel pressure is released before removing fuel line or fittings, as fuel system is under pressure and may cause personal injury. See «FUEL SYSTEM PRESSURE RELEASE»(ref-157234-S40563730662003080700000) .
3. When using DIAGNOSTIC TESTS for diagnosis, DO NOT skip any steps, or incorrect diagnosis may result. When instructed to disconnect any connector, check that the connector is clean and in good condition after disconnecting the connector. Repair or clean connector if necessary. Always perform indicated verification procedure after repairs are made. Verification tests are listed at the end of the diagnostic tests.
4. DO NOT use 12-volt test light when checking 5-volt supply circuit, CCD Bus circuit, Camshaft Position (CMP) Sensor Signal circuit, Crankshaft Position (CKP) Sensor Signal circuit, Oxygen Sensor (O2S) Signal circuit or Vehicle Speed Sensor (VSS) Signal circuit or Powertrain Control Module (PCM) may be damaged.
5. When using a jumper wire, ensure either jumper wire or circuit is fuse-protected.
6. Before disconnecting any control module connector, ensure ignition is off before removing connector.
7. When checking voltage or continuity at any control module, probe control module connector from pin side. DO NOT backprobe connector unless instructed to in test procedure. DO NOT probe wires through the insulation.
8. DO NOT cause short circuits when performing electrical tests. This may cause additional Diagnostic Trouble Codes (DTC) to be set, making diagnosis of original problem more difficult.
9. Use specified test equipment when performing electrical tests.
10. DO NOT prolong testing of fuel injectors or engine may hydrostatically lock.
11. If replacing PCM, the correct vehicle mileage and vehicle identification number must be programmed into the PCM to prevent DTCs from being set in controller anti-lock brake system module and air bag control module. See «POWERTRAIN CONTROL MODULE»(ref-157234-S31537141772003080700000) under PROGRAMMING.

INTERMITTENT CONDITION

For intermittent conditions (Scheme 391)

Scheme 391

POWERTRAIN CONTROL MODULE

Note. If replacing Powertrain Control Module (PCM), the correct vehicle mileage and Vehicle Identification Number (VIN) must be programmed into PCM to prevent Diagnostic Trouble Codes (DTC) from being set in Controller Anti-Lock Brake (CAB) module and Air Bag Control Module (ACM).

Connect scan tool to Data Link Connector (DLC). DLC is located below driver's side of instrument panel. see scheme 4 Turn ignition on. Using scan tool, enter correct VIN and mileage into PCM. Using scan tool manufacturer's instructions, clear DTCs from CAB module and ACM.

DRIVE CYCLES

Manufacturer does not provide a specific drive cycle to run all the monitors. Performing Powertrain Verification Test VER-5 will run most of the monitors. See POWERTRAIN VERIFICATION TEST VER-5 under VERIFICATION TESTS. Verification tests are normally referred to after performing a code related diagnostic test. To run all the monitors, it may be necessary to perform more than one powertrain verification test. See appropriate POWERTRAIN VERIFICATION TEST under VERIFICATION TESTS.

SUMMARY

If no Diagnostic Trouble Codes (DTCs) are present and a no start condition exists, proceed to NO-START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article. If no DTCs are present and a driveability condition exists, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.).

FUEL SYSTEM PRESSURE RELEASE

1. Remove fuel tank cap. Remove Fuel Pump Relay from Power Distribution Center (PDC). PDC is located in left side of engine compartment. Start engine. Allow engine to run until engine stalls. Attempt to start engine until it will no longer run. Turn ignition off.
2. Disconnect any fuel injector harness connector. Connect a jumper wire between one terminal of fuel injector (component side) and positive battery terminal.
3. Momentarily connect another jumper wire between remaining electrical terminal at fuel injector (component side) and negative battery terminal for a few seconds. DO NOT apply voltage to fuel injector for extended time or fuel injector may be damaged. This operates fuel injector and releases fuel pressure.
4. Remove jumper wires. Install fuel injector harness connector. Fuel pressure should now be released. Reinstall Fuel Pump Relay. Diagnostic Trouble Code (DTC) may have been stored in Powertrain Control Module (PCM) due to the removal of Fuel Pump Relay. For clearing DTC from PCM, see «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-157234-S04141451922003080700000) under SELF-DIAGNOSTIC SYSTEM.

SKIS VERIFICATION

For testing procedures (Scheme 392)

Scheme 392

RAM PICKUP 1500

See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS R1500 article in ELECTRICAL.

RAM PICKUP 2500

See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS R2500 article in ELECTRICAL.

RAM PICKUP 3500

See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS R3500 article in ELECTRICAL.