Home ReviewsRefund
Home/Dodge/Cab & Chassis R2500/Dodge Cab & Chassis R2500 (1996-2006)/Repair manual/Testing & Diagnostics/Engine Controls Self-Diagnostics - Diesel: Other
Contents Wiring diagrams Section: Testing & Diagnostics All sections

Engine Controls Self-Diagnostics - Diesel: Other Dodge Cab & Chassis R2500

Testing & Diagnostics ~2586 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.

  1. Cylinder Compression
  2. ECM Or PCM Connector Engagement
  3. ECM Or PCM System Ground
  4. Excessive Oil Consumption
  5. Exhaust System
  6. Fuel Injector Mechanical Faults
  7. Fuel Pressure
  8. 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 Diagnostic Trouble Codes (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).

Hard Failures

Hard failures cause MIL to illuminate and remain on until problem is repaired. This means the defect is there every time the Engine Control Module (ECM) and Powertrain Control Module (PCM) checks that circuit or function. If MIL light 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, ECM or 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. 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.

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 (DTC) will be retained in Engine Control Module (ECM) or Powertrain Control Module (PCM) memory. If related failure does not reoccur within a certain time frame, related DTC will be erased from ECM or PCM memory. Most intermittent failures are caused by a sensor, electrical connector or wiring related problems. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - RAM PICKUP - DIESEL 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.
  2. 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.
  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 test after repairs are made. Verification tests are listed at the end of diagnostic tests.
  4. DO NOT use 12-volt test light when checking 5-volt or 8-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.
  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. Ohms cannot be measured if voltage is present on circuit being tested. Disconnect voltage source before measuring resistance.
  9. 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.
  10. Use specified test equipment when performing electrical tests.
  11. 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-97349-S33491306622001050200000) under PROGRAMMING.
  12. 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-97349-S35953418412001050200000) under PROGRAMMING.

ENGINE CONTROL MODULE

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.

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

  1. To program PCM and clear DTCs from CAB and SRS modules, connect scan tool to Data Link Connector (DLC). DLC is located below driver's side of instrument panel. (Схема №1) Turn ignition on with engine off.
  2. Using scan tool, enter correct VIN and mileage into PCM. Using scan tool manufacturer's instructions, clear DTCs from CAB and SRS modules.

NO RESPONSE FROM ENGINE CONTROL MODULE

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article. After completing any repairs, perform TEST VER-1A under VERIFICATION TESTS.

  1. Turn ignition on. Using scan tool, attempt to communicate with Powertrain Control Module (PCM). If scan tool communicates with PCM, go to next step. If scan tool does not communicate with PCM, go to «NO RESPONSE FROM ENGINE CONTROL MODULE OR POWERTRAIN CONTROL MODULE»(ref-97349-S38627483272001051600000).
  2. Turn ignition off. Check power and grounds for Engine Control Module (ECM). See «CHECKING ENGINE CONTROL MODULE POWER & GROUND CIRCUITS»(ref-97349-S32201042052001050300000) under DIAGNOSTIC CIRCUIT CHECK. Repair as necessary. If power and grounds for ECM are okay, go to next step.
  3. Ensure ignition is off. Disconnect ECM connector. (Схема №2) Disconnect scan tool from Data Link Connector (DLC). Using DVOM, measure resistance between ground and terminal No. 39 (Dark Green wire) on ECM connector. (Схема №12) If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Green wire.
  4. Using DVOM, measure resistance of Dark Green wire between terminal No. 39 on ECM connector and terminal No. 6 on DLC. (Схема №11)and (Схема №12). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Green wire.
  5. Using DVOM, measure resistance of Pink/Dark Blue wire between terminal No. 38 on ECM connector and terminal No. 7 on DLC. If resistance is less than 5 ohms, replace ECM. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article. If resistance is 5 ohms or more, repair open in Pink/Dark Blue wire.

NO RESPONSE FROM POWERTRAIN CONTROL MODULE

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article. After completing any repairs, perform TEST VER-1A under VERIFICATION TESTS.

  1. Turn ignition on. Using scan tool, attempt to communicate with Engine Control Module (ECM). ECM may also be referred to as Cummins Controller. If scan tool communicates with ECM, go to next step. If scan tool does not communicate with ECM, go to «NO RESPONSE FROM ENGINE CONTROL MODULE OR POWERTRAIN CONTROL MODULE»(ref-97349-S38627483272001051600000).
  2. Turn ignition off. Check power and grounds for Powertrain Control Module (PCM). See «CHECKING POWERTRAIN CONTROL MODULE POWER & GROUND CIRCUITS»(ref-97349-S04818459242001050300000) under DIAGNOSTIC CIRCUIT CHECK. Repair as necessary. If power and grounds for PCM are okay, go to next step.
  3. Ensure ignition is off. Disconnect PCM connector C3. (Схема №3) Disconnect scan tool from Data Link Connector (DLC). Using DVOM, measure resistance between ground and terminal No. 29 (White/Violet wire) on PCM connector C3. (Схема №22) If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in White/Violet wire.
  4. Using DVOM, measure resistance of White/Violet wire between terminal No. 29 on PCM connector C3 and terminal No. 14 on DLC. (Схема №11)and (Схема №22). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in White/Violet wire.
  5. Using DVOM, measure resistance of Pink/Dark Blue wire between terminal No. 27 on PCM connector C3 and terminal No. 7 on DLC. If resistance is less than 5 ohms, replace PCM. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article. If resistance is 5 ohms or more, repair open in Pink/Dark Blue wire.

NO RESPONSE FROM ENGINE CONTROL MODULE OR POWERTRAIN CONTROL MODULE

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article. After completing any repairs, perform TEST VER-1A under VERIFICATION TESTS.

  1. Turn ignition off. Check power and grounds for Engine Control Module (ECM) and Powertrain Control Module (PCM). See «DIAGNOSTIC CIRCUIT CHECK»(ref-97349-S17456425812001050300000). Repair as necessary. If power and grounds for ECM and PCM are okay, go to next step.
  2. Ensure ignition is off. Reconnect all disconnected components. Disconnect PCM connectors. (Схема №3) Turn ignition on. Using scan tool, attempt to communicate with ECM. If scan tool does not communicate with ECM, go to next step. If scan tool communicates with ECM, replace PCM. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article.
  3. Turn ignition off. Disconnect scan tool. Disconnect ECM connector. (Схема №2) Using DVOM, measure voltage at terminal No. 7 (Pink/Dark Blue wire) on Data Link Connector (DLC). (Схема №11) If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to voltage in Pink/Dark Blue wire.
  4. Ensure scan tool, ECM and PCM are disconnected. Using DVOM, measure resistance between terminal No. 7 (Pink/Dark Blue wire) on DLC and terminals No. 6 (Dark Green wire) and No. 14 (White/Violet wire). If resistance at all terminals is 5 ohms or more, go to next step. If resistance at either terminal is less than 5 ohms, repair short between SCI circuits for terminals indicating less than 5 ohms.
  5. Using DVOM, measure resistance between ground and terminal No. 7 (Pink/Dark Blue wire) on DLC. If residence is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Pink/Dark Blue wire.
  6. Using DVOM, measure resistance of Pink/Dark Blue wire between terminal No. 38 on ECM connector and terminal No. 7 on DLC. (Схема №11)and (Схема №22). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Pink/Dark Blue wire.
  7. Ensure ignition is off. Ensure scan tool is disconnected. Disconnect negative battery cable. Using DVOM, measure resistance between ground and terminals No. 4 (Black/Light Green wire) and No. 5 (Black/Tan wire) at DLC. If resistance at either terminal is 5 ohms or more, repair open in circuits for terminals indicating 5 ohms or more. If resistance at all terminals is less than 5 ohms, replace ECM. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article.

SUMMARY

If no diagnostic trouble code is present but driveability problem still exists, proceed to TROUBLE SHOOTING - NO CODES - RAM PICKUP - DIESEL article for diagnosis by symptom.

CHECKING ENGINE CONTROL MODULE POWER & GROUND CIRCUITS

  1. Turn ignition off. Locate and disconnect Engine Control Module (ECM) connector. (Схема №2) Using a test light connected to ground, probe ECM connector terminal No. 48 (Red/White wire) and No. 50 (Red/White wire). (Схема №12) 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 connector and fuse No. 3 (20-amp) located in Power Distribution Center (PDC).
  2. Turn ignition on. Using test light connected to ground, probe ECM 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.
  3. Turn ignition off. Using a test light connected to battery voltage, probe ECM connector terminal No. 30 (Black/Tan wire) and No. 49 (Black/Tan wire). If test light illuminates brightly at both terminals, power and ground circuits are okay. ECM will need to be diagnosed further. See appropriate diagnosis and repair procedure under COMMUNICATIONS under SYSTEM TESTS in BODY CONTROL MODULES - RAM PICKUP article in ACCESSORIES & EQUIPMENT. 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 connector and ground.

CHECKING POWERTRAIN CONTROL MODULE POWER & GROUND CIRCUITS

  1. Turn ignition off. Locate and disconnect Powertrain Control Module (PCM) connectors. (Схема №3) Using a test light connected to ground, probe PCM connector C1 terminal No. 22 (Red/White wire). (Схема №22) 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 connector and fuse No. 3 (20-amp) located in Power Distribution Center (PDC).
  2. Turn ignition on. Using test light connected to ground, probe PCM 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 connector and fuse No. 9 (10-amp) located in junction block.
  3. Turn ignition off. Using a test light connected to battery voltage, probe PCM connector C1 terminals No. 31 (Black/Tan wire) and No. 32 (Black/Tan wire). If test light illuminates brightly at both terminals, power and ground circuits are okay. ECM will need to be diagnosed further. See appropriate diagnosis and repair procedure under COMMUNICATIONS under SYSTEM TESTS in BODY CONTROL MODULES - RAM PICKUP article in ACCESSORIES & EQUIPMENT. If test light is dim or does not illuminate at one or both terminals, repair open or high resistance in Black/Tan wire between PCM connector and ground.

More articles — Engine Controls Self-Diagnostics - Diesel