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Engine Controls Self-Diagnostics - Diesel: Other Dodge Pickup R2500

Testing & Diagnostics 1 illustration ~2116 words

Monitored Circuits

The Engine Control Module (ECM) and Powertrain Control Module (PCM) monitor several circuits and components in the powertrain system. If a problem exists which affects vehicle emissions, a Diagnostic Trouble Code (DTC) will be stored in ECM or PCM. With certain DTCs, if the problem is repaired or ceases to exist, MIL will turn off after 3 good trips. The ECM or PCM will erase the DTC after 40 warm-up cycles.

Non-Monitored Circuits

The Engine Control Module (ECM) and Powertrain Control Module (PCM) do not monitor all circuits, conditions and systems that could cause a malfunction or driveability problem. However, problems with these systems may cause ECM or PCM to store DTCs for other systems or components.

For example, a cylinder with low compression will not cause a DTC directly, but could cause a misfire which may cause ECM to store a DTC. The major non-monitored circuits are identified as follows.

Cylinder Compression
ECM Or PCM Connector Engagement
ECM Or PCM System Ground
Excessive Oil Consumption
Exhaust System
Fuel Injector Mechanical Faults
Fuel Pressure
Restricted Or Leaking Air Intake System

Trip Indicator

The trip is essential for running monitors and turning off the Malfunction Indicator Light (MIL). A trip is defined as a set of vehicle operating conditions that must be met for a specific monitor to run. All trips begin with an ignition key cycle. Good trip counters are, specific good trip, fuel system good trip and misfire good trip.

Warm-Up Cycles

Once the Malfunction Indicator Light (MIL) has been turned off by the Good Trip Counter, the PCM will automatically switch to a warm-up cycle counter that can be viewed by the DRBIII® scan tool. Warm-up cycles are used to clear DTCs and freeze frame data from Powertrain Control Module (PCM) memory. Forty warm-up cycles are necessary to clear DTCs 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).

Hard Failures

A Diagnostic Trouble Code (DTC) that comes back within one cycle of the ignition key is considered a hard code. This means the defect is present when the PCM checks that circuit or function. If MIL comes on and remains on during vehicle operation, cause of malfunction must be determined by retrieving DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES .

Codes that are for OBD-II monitors will not set with just the ignition key on. Comparing these to non-emission codes, they will seem like an intermittent. These codes require a set of parameters to be performed (called a trip). Most OBD-II DTCs will set after 2 trip failures, some will set in one, turning on the MIL. These DTCs require 3 consecutive no failure trips to extinguish the MIL, followed by 40 warm-up cycles to erase the DTC.

Intermittent Failures

A Diagnostic Trouble Code (DTC) that is not present every time the PCM checks the circuit, is an intermittent code. Most intermittent failures are caused by electrical connector or wiring related problems. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - RAM PICKUP - DIESEL article. Intermittents that come and go like this are the most difficult to diagnose; they must be looked for under specific conditions that cause them.

SERVICE PRECAUTIONS

Before proceeding with system diagnosis, following precautions must be followed

Before performing any testing procedures, check for any related Technical Service Bulletins (TSB).
High-pressure fuel lines are under extreme pressure. High fuel injection pressure may cause personal injury. Use care when working around high-pressure fuel lines.
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 test after repairs are made. Verification tests are listed at the end of diagnostic tests.
DO NOT use 12-volt test light when checking 5-volt supply circuit, CCD bus circuit, camshaft position sensor signal circuit or vehicle speed sensor signal circuit, Engine Control Module (ECM) or Powertrain Control Module (PCM) may be damaged.
When using a jumper wire, ensure either jumper wire or circuit is fuse-protected.
Before disconnecting any control module connector, ensure ignition is off before removing connector.
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.
Resistance (Ohms) cannot be measured if voltage is present on circuit being tested. Disconnect voltage source before measuring resistance.
DO NOT cause short circuits when performing electrical tests. This will cause additional Diagnostic Trouble Codes (DTC) to be stored, making diagnosis of original problem more difficult.
Use specified test equipment when performing electrical tests.
When battery is disconnected, ECM is disconnected or replaced, or Accelerator Pedal Position Sensor (APPS) has been disconnected or replaced, ECM must be programmed to match the APPS. For ECM programming, see «ENGINE CONTROL MODULE»(ref-157446-S24747081842003081400000) under PROGRAMMING.
If PCM is replaced, the correct vehicle mileage and Vehicle Identification Number (VIN) must be programmed into PCM to prevent DTCs from being stored in Controller Anti-Lock Brake (CAB) module and Supplemental Restraint System (SRS) module. See «POWERTRAIN CONTROL MODULE»(ref-157446-S11473747202003081400000) under PROGRAMMING.

INTERMITTENT CONDITION

For intermittent condition testing (Scheme 822)

Scheme 822

Scheme 822: INTERMITTENT CONDITION

ENGINE CONTROL MODULE

Note. Engine Control Module (ECM) may also be referred to as Cummins Controller.

ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. see scheme 5 When battery is disconnected, ECM is disconnected or replaced, or Accelerator Pedal Position Sensor (APPS) has been disconnected or replaced, ECM must be programmed to match the APPS. For ECM programming, see ENGINE CONTROL MODULE under PROGRAMMING.

POWERTRAIN CONTROL MODULE

Powertrain Control Module (PCM) is located at passenger's side rear corner of engine compartment. see scheme 12 If replacing PCM, PCM must be properly programmed. See POWERTRAIN CONTROL MODULE under PROGRAMMING.

Note. If battery is disconnected, Engine Control Module (ECM) is disconnected or replaced, or Accelerator Pedal Position Sensor (APPS) has been disconnected or replaced, ECM must be programmed to match the APPS.

Ensure all components are connected. Turn ignition on with engine off. Slowly depress accelerator pedal to the floor and release accelerator pedal to idle position one time. This ensures that APPS calibration has been programmed into the ECM. Turn ignition off.

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 stored in Controller Anti-Lock Brake (CAB) module and Supplemental Restraint System (SRS) module.

To program PCM and clear DTCs from CAB and SRS modules, connect DRBIII® scan tool to Data Link Connector (DLC). DLC is located below driver's side of instrument panel. see scheme 4 Turn ignition on with engine off.
Using scan tool, enter correct VIN and mileage into PCM. Using scan tool manufacturer's instructions, clear DTCs from CAB and SRS modules.

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.

NO RESPONSE FROM ENGINE CONTROL MODULE

Note. For component locations, see COMPONENT LOCATIONS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For circuit identification and wiring diagram, see WIRING DIAGRAMS . If Engine Control Module (ECM) or Powertrain Control Module (PCM) is replaced, control module must be reprogrammed. See PROGRAMMING . After each repair procedure has been completed, reconnect all components and connectors. After completing any repairs, perform POWERTRAIN VERIFICATION TEST VER-1 under VERIFICATION TESTS.

Monitor & Set Conditions

Attempt To Communicate With The PCM
Check ECM Powers & Grounds
SCI Receive Circuit Shorted To Ground
SCI Receive Circuit Open
SCI Transmit Circuit Open
ECM

NO RESPONSE FROM POWERTRAIN CONTROL MODULE

Attempt To Communicate With The ECM
Check PCM Powers & Grounds
SCI Receive Circuit Shorted To Ground
SCI Receive Circuit Open
SCI Transmit Circuit Open
PCM

NO RESPONSE FROM ENGINE CONTROL MODULE & POWERTRAIN CONTROL MODULE

Note. For component locations, see COMPONENT LOCATIONS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For circuit identification and wiring diagram, see WIRING DIAGRAMS article. If Engine Control Module (ECM) or Powertrain Control Module (PCM) is replaced, control module must be reprogrammed. See PROGRAMMING . After each repair procedure has been completed, reconnect all components and connectors. After completing any repairs, perform POWERTRAIN VERIFICATION TEST VER-1 under VERIFICATION TESTS.

Check ECM & PCM Powers & Grounds
PCM - SCI Transmit
SCI Transmit Circuit Shorted To Voltage
SCI Circuits Shorted Together
SCI Transmit Circuit Shorted To Ground
SCI Transmit Circuit Open
Ground Circuits At DLC Open
ECM

SUMMARY

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

Checking Power & Ground Circuits

Turn ignition off. Disconnect Engine Control Module (ECM) harness connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Using a test light connected to ground, probe ECM harness connector terminals No. 48 and 50 (Red/White wires). If test light illuminates brightly at both terminals, go to next step. If test light is dim or does not illuminate at one or both terminals, repair open or high resistance in appropriate Red/White wire between ECM harness connector and fuse No. 3 (20-amp) located in Power Distribution Center (PDC).
Turn ignition on. Using test light connected to ground, probe ECM harness connector terminal No. 5 (Light Green/Black wire). If test light illuminates brightly, go to next step. If test light is dim or does not illuminate, repair open or high resistance in Light Green/Black wire between ECM connector and fuse No. 9 (10-amp) located in junction block.
Turn ignition off. Using a test light connected to battery voltage, probe ECM connector terminals No. 30 and 49 (Black/Tan wires). If test light illuminates brightly at both terminals, ECM ground circuits are okay. ECM power and ground circuit test is complete. If test light is dim or does not illuminate at one or both terminals, repair open or high resistance in appropriate Black/Tan wire between ECM harness connector and ground.

Turn ignition off. Disconnect Powertrain Control Module (PCM) harness connectors. PCM is located at passenger's side rear corner of engine compartment. Using a test light connected to ground, probe PCM harness connector C1 terminal No. 22 (Red/White wire). If test light illuminates brightly, go to next step. If test light is dim or does not illuminate, repair open or high resistance in Red/White wire between PCM harness connector and fuse No. 3 (20-amp) located in Power Distribution Center (PDC).
Turn ignition on. Using test light connected to ground, probe PCM harness connector C1 terminal No. 2 (Light Green/Black wire). If test light illuminates brightly, go to next step. If test light is dim or does not illuminate, repair open or high resistance in Light Green/Black wire between PCM harness connector and fuse No. 9 (10-amp) located in junction block.
Turn ignition off. Using a test light connected to battery voltage, probe PCM harness connector C1 terminals No. 31 and 32 (Black/Tan wires). If test light illuminates brightly at both terminals, PCM ground circuits are okay. PCM power and ground circuit test is complete. If test light is dim or does not illuminate at one or both terminals, repair open or high resistance in appropriate Black/Tan wire between PCM harness connector and ground.

RAM PICKUP R2500

See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

RAM PICKUP R3500