Engine System Testing & Engine Component Testing - Ram Pickup - Diesel: Other Dodge Cab & Chassis R2500

INTAKE MANIFOLD AIR HEATER (IMAH) SYSTEM

Note. For additional testing procedures on IMAH system, see DTC P0380: INTAKE AIR HEATER RELAY NO. 1 CONTROL CIRCUIT, DTC P0382: INTAKE AIR HEATER RELAY NO. 2 CONTROL CIRCUIT and/or P1291: NO TEMPERATURE RISE SEEN FROM INTAKE AIR HEATERS under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

Checking Intake Air Heater No. 1

Note. After completing any repairs, perform TEST VER-2A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

1. Ensure ignition is on with engine off. Using DVOM, check and record voltage at positive battery terminal. While monitoring battery voltage, using scan tool, briefly actuate intake air heater No. 1 and note battery voltage. DO NOT actuate intake air heater No. 1 for any longer than possible, as intake air heater draws a large amount of current. Stop actuation of intake air heater No. 1. If battery voltage drops less than.5 volt when intake air heater No. 1 is actuated, go to next step. If battery voltage drops.5 volt or more when intake air heater No. 1 is actuated, intake air heater relay No. 1 is operating properly. Test is complete.
2. Using DVOM, perform voltage drop test on cable between intake air heater relay No. 1 and terminal on intake air heater assembly. Intake air heater relay No. 1 is located on bracket near driver's side battery. (Scheme 46) Intake air heater assembly located on top of intake manifold. (Scheme 47) If voltage drop is less than.2 volt, go to next step. If voltage drop is.2 volt or more, repair high resistance on cable between intake air heater relay No. 1 and terminal on intake air heater assembly.
3. Perform voltage drop test on cable between battery and intake air heater relay No. 1. If voltage drop is less than.2 volt, replace intake air heater assembly. If voltage drop is.2 volt or more, repair high resistance on cable between battery and intake air heater relay No. 1.

Scheme 46

Scheme 47

Checking Intake Air Heater No. 2

Note. After completing any repairs, perform TEST VER-2A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

1. Ensure ignition is on with engine off. Using DVOM, check and record voltage at positive battery terminal. While monitoring battery voltage, using scan tool, briefly actuate intake air heater No. 2 and note battery voltage. DO NOT actuate intake air heater No. 2 for any longer than possible, as intake air heater draws a large amount of current. Stop actuation of intake air heater No. 2. If battery voltage drops less than.5 volt when intake air heater No. 2 is actuated, go to next step. If battery voltage drops.5 volt or more when intake air heater No. 2 is actuated, intake air heater relay No. 2 is operating properly. Test is complete.
2. Perform voltage drop test on cable between intake air heater relay No. 2 and terminal on intake air heater assembly. Intake air heater relay No. 2 is located on bracket near driver's side battery. (Scheme 46) Intake air heater assembly located on top of intake manifold. (Scheme 47) If voltage drop is less than.2 volt, go to next step. If voltage drop is.2 volt or more, repair high resistance on cable between intake air heater relay No. 2 and terminal on intake air heater assembly.
3. Perform voltage drop test on cable between battery and intake air heater relay No. 2. If voltage drop is less than.2 volt, replace intake air heater assembly. If voltage drop is.2 volt or more, repair high resistance on cable between battery and intake air heater relay No. 2.

INTERCOOLER

Cleaning and inspection procedures for intercooler is the only information available from manufacturer. See INTERCOOLER under AIR INDUCTION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article.

TURBOCHARGER

Note. Manufacturer does not recommend turbocharger disassembly. Turbocharger overhaul should be performed only by an authorized repair facility.

TURBOCHARGER WASTEGATE

For turbocharger wastegate testing, see DTC P0234: TURBO BOOST LIMIT EXCEEDED under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article. Turbocharger wastegate adjustment procedures are not available unless a NEW turbocharger wastegate or actuator is installed. See TURBOCHARGER WASTEGATE under AIR INDUCTION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article.

COMPUTERIZED ENGINE CONTROLS

Note. The following test procedures will test for proper power and ground circuits at ECM and PCM.

ENGINE CONTROL MODULE (ECM)

1. Turn ignition off. Locate and disconnect Engine Control Module (ECM) connector. (Scheme 48) Using a test light connected to ground, probe ECM connector terminal No. 48 (Red/White wire) and No. 50 (Red/White wire). (Scheme 49) If test light illuminates brightly at both terminals, go to next step. If test light is dim or does not illuminate at all at either terminal, repair open or high resistance in 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 at all, 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 terminals 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 all at either terminal, repair open or high resistance in Black/Tan wire between ECM connector and ground.

Locating Engine Control Module (ECM). Scheme 48

Scheme 49

POWERTRAIN CONTROL MODULE (PCM)

1. Turn ignition off. Locate and disconnect Powertrain Control Module (PCM) connectors. (Scheme 50) Using a test light connected to ground, probe PCM connector C1 terminal No. 22 (Red/White wire). (Scheme 51) If test light illuminates brightly, go to next step. If test light is dim or does not illuminate at all, 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 at all, 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. PCM 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 all at either terminal, repair open or high resistance in Black/Tan wire between PCM connector and ground.

Scheme 50

Scheme 51

ACCELERATOR PEDAL POSITION SENSOR

Note. For wiring diagram, see WIRING DIAGRAMS article. After completing any repairs, perform TEST VER-5A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

1. Ensure ignition is off. Inspect Accelerator Pedal Position Sensor (APPS) and Engine Control Module (ECM) connectors for miswired terminals. APPS is located on bracket, just above fuel injection pump. (Scheme 52) ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. (Scheme 48) If terminals are not miswired, go to next step. If terminals are miswired, repair as necessary.
2. Turn ignition on with engine off. Using scan tool in SENSORS mode, read APPS voltage while moving throttle from lower stop (idle position) to upper stop (full throttle position). If APPS voltage does not vary from less than one volt at closed position to more than 3 volts at open position, go to next step. If APPS voltage varies from less than one volt at closed position to more than 3 volts at open position, test is complete.
3. Check operation of throttle to ensure throttle moves freely from lower stop (idle position) to upper stop (full throttle position). If throttle moves freely between both positions, replace APPS. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article. If throttle does not move freely between both positions, repair throttle as necessary.

Locating Accelerator Pedal Position Sensor. Scheme 52

BATTERY TEMPERATURE SENSOR

Battery temperature sensor is snapped into battery tray, below driver's side battery. Testing of actual battery temperature sensor is not available. If problem exists in battery temperature sensor or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in PCM. See DTC P1492: AMBIENT/BATT TEMP SENSOR VOLTS TOO HIGH and/or DTC P1493: AMBIENT/BATT TEMP SENSOR VOLTS TOO LOW under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

Brake Switch Circuit

Note. For wiring diagram, see WIRING DIAGRAMS article. After completing any repairs, perform TEST VER-2A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

1. If vehicle is equipped with speed control, go to next step. If vehicle is not equipped with speed control, go to step 3.
2. Turn ignition on with engine off. Using scan tool, actuate speed control solenoids. Using 12-volt test light, backprobe terminal No. 4 (Dark Blue/Red wire) on brake switch connector with brake switch connector installed. (Scheme 53) Depress and release brake pedal while noting test light operation. If test light goes off when brake pedal is depressed and comes on when pedal is released, go to next step. If test light does not go off when brake pedal is depressed and come on when brake pedal is released, replace brake switch, as brake switch is nonadjustable and can only be adjusted when NEW brake switch is installed.
3. Ensure brake pedal is not depressed. Using 12-volt test light, backprobe terminal No. 5 (White/Tan wire) on brake switch connector with brake switch connector installed. (Scheme 53) Depress brake pedal while noting test light operation. If test light comes on when pedal is depressed and goes off when brake pedal is released, go to next step. If test light does not come on when pedal is depressed and off when brake pedal is released, go to step 9.
4. Turn ignition on with engine off. Using scan tool, monitor brake switch input status while depressing and releasing brake pedal. If scan tool does not indicate PRESSED and RELEASED while depressing and releasing brake pedal, go to next step. If scan tool indicates PRESSED and RELEASED while depressing and releasing brake pedal, brake switch is operating properly at this time.
5. Turn ignition off. Disconnect brake switch connector. Using DVOM, check resistance between ground and terminal No. 2 (Black/Light Green wire) on brake switch connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Black/Light Green wire between brake switch and ground connection located behind driver's side kick panel.
6. Using 12-volt test light, check for voltage at terminal No. 6 (Pink/Dark Blue wire) on brake switch connector. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open on Pink/Dark Blue wire between battery, fuse No. 5 (20-amp) and brake switch. (Scheme 54) Fuse No. 5 is located in power distribution center at driver's side front corner of engine compartment. (Scheme 50)
7. Ensure ignition is off and brake switch connector is still disconnected. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. (Scheme 50) Using DVOM, check resistance between terminal No. 1 (White/Pink wire) on brake switch connector and terminal No. 24 (White/Pink wire) on PCM connector C3. (Scheme 51) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on White/Pink wire between brake switch, joint connector No. 1 and PCM. Joint connector No. 1 is located in power distribution center at driver's side front corner of engine compartment.
8. Ensure ignition is off. Reinstall PCM connectors. Connect jumper wire between ground and terminal No. 1 (White/Pink wire) on brake switch connector. Using scan tool, read brake switch input status. If brake switch input status indicates RELEASED, replace brake switch. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If brake switch input status does not indicate RELEASED, replace PCM. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article.
9. Using 12-volt test light, check for voltage at terminal No. 6 (Pink/Dark Blue wire) on brake switch connector. If test light illuminates brightly, replace brake switch. If test light does not illuminate brightly, repair open on Pink/Dark Blue wire between battery, fuse No. 5 (20-amp) and brake switch. Fuse No. 5 is located in power distribution center at driver's side front corner of engine compartment.

Scheme 53

Scheme 54

CAMSHAFT POSITION SENSOR

Camshaft Position (CMP) sensor is located below fuel injection pump. (Scheme 55) Testing of actual CMP sensor is not available. If problem exists in CMP sensor or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in PCM. See DTC P0341: CAMSHAFT POSITION (CMP) SENSOR SIGNAL MISSING, P0342: CAMSHAFT POSITION (CMP) SENSOR SUPPLY VOLTAGE TOO LOW and/or P0343: CAMSHAFT POSITION (CMP) SENSOR SUPPLY VOLTAGE TOO HIGH under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

Locating CMP Sensor. Scheme 55

ENGINE COOLANT TEMPERATURE SENSOR

Note. After completing any repairs, perform TEST VER-5A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

Scheme 56

1. Turn ignition on with engine off. Using scan tool, read Engine Coolant Temperature (ECT) sensor value. If engine coolant temperature is more than 180°F (82.2°C), allow engine to cool until engine coolant temperature is less than 150°F (65.6°C) before proceeding.
2. With engine coolant temperature at 150°F (65.6°C) or less, start engine and allow engine to idle. While monitoring scan tool, operate engine until engine coolant temperature is at least 180°F (82.2°C). If engine coolant temperature becomes at least 180°F (82.2°C), test is complete. If engine coolant temperature does not become at least, check for cooling system problems. If no cooling system problems exist, replace ECT sensor. ECT sensor is located at front of cylinder head, near thermostat housing. (Scheme 56)

Fuel Heater

Fuel heater temperature sensor is part of fuel heater and is serviced as an assembly. Testing for fuel heater temperature sensor is not available. See FUEL HEATER under FUEL SYSTEM for diagnosis of fuel heater system.

Fuel Injection Pump

Fuel heater temperature sensor is part of fuel injection pump and is serviced as an assembly. Testing for fuel injection pump temperature sensor is not available. If problem exists in fuel injection pump temperature sensor or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in PCM. See DTC P0168: DECREASED ENGINE PERFORMANCE DUE TOO HIGH INJECTION PUMP FUEL TEMP and/or P0180: FUEL INJECTION PUMP TEMP OUT OF RANGE under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

INTAKE AIR TEMPERATURE SENSOR

Intake manifold air temperature sensor is located on top of intake manifold, behind intake manifold air heater. (Scheme 57) For additional testing procedures, see DTC P0112: INTAKE AIR TEMPERATURE (IAT) SENSOR VOLTAGE LOW and/or DTC P0113: INTAKE AIR TEMPERATURE (IAT) SENSOR VOLTAGE HIGH tests under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

Note. When performing this test, DO NOT allow more than 5 minutes between measuring temperature of Intake Air Temperature (IAT) sensor with scan tool and measuring air temperature on inside of intake manifold for IAT sensor with temperature probe.

Note. After completing any repairs, perform TEST VER-2A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

Scheme 57

1. Turn ignition on with engine off. Using scan tool, measure and record temperature of IAT sensor. Turn ignition off. Remove IAT sensor. IAT sensor is located on driver's side rear corner of cylinder head. (Scheme 57)
2. Using temperature probe, quickly measure air temperature on inside of intake manifold for IAT sensor. If temperature of IAT sensor on scan tool is within 10 degrees of temperature obtained on temperature probe, IAT sensor is okay. Test is complete. If temperature of IAT sensor on scan tool is not within 10 degrees of temperature obtained on temperature probe, replace IAT. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article.

OIL PRESSURE SENSOR/SWITCH

Oil pressure sensor/switch is located below ECM. (Scheme 48) Testing of actual oil pressure sensor/switch is not available. If problem exists in oil pressure sensor/switch or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in PCM. See DTC P0522: OIL PRESSURE VOLTAGE TOO LOW, P0523: OIL PRESSURE VOLTAGE TOO HIGH and/or P0524: OIL PRESSURE TOO LOW under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

MAP SENSOR

Note. After completing any repairs, perform TEST VER-5A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

Ensure ignition is off. Locate MAP sensor. (Scheme 57) Using a "T" fitting, install pressure gauge at manifold pressure source. Start engine and allow engine to idle. If engine will not idle, maintain engine at constant RPM above idle. Note manifold pressure reading on pressure gauge. Using scan tool, read Manifold Air Pressure (MAP) sensor pressure. If MAP sensor pressure displayed on scan tool is within one inch of manifold pressure reading on pressure gauge, MAP sensor is operating properly. Test is complete. If MAP sensor pressure displayed on scan tool is not within one in. Hg of manifold pressure reading on pressure gauge, replace MAP sensor. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article.

PARK/NEUTRAL SWITCH (A/T MODELS)

See CHECKING PARK/NEUTRAL (P/N) SWITCH (A/T MODELS) under MISCELLANEOUS CONTROLS.

VEHICLE SPEED SENSOR

Vehicle Speed Sensor (VSS) is a magnetic pick-up triggered by park gear lugs. Park gear lugs operate in the same manner as a tone wheel. VSS is located in the overdrive gear case at rear of transmission. Testing of actual VSS is not available. If problem exists in VSS or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in PCM. See DTC P0500: NO VEHICLE SPEED SENSOR SIGNAL and/or P0501: VEHICLE SPEED SENSOR RATIONALITY under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

WATER-IN-FUEL (WIF) SENSOR

1. WATER-IN-FUEL (WIF) sensor is located in bottom of fuel filter/water separator. Testing information is not available. When ignition switch is first turned to ON position, WIF warning light should come on for 2 seconds to perform bulb and wiring circuit test and then go off. WIF warning light is located on instrument panel, just below the tachometer. If WIF light does not operate properly, go to «WATER-IN-FUEL LIGHT»(ref-97350-S22251591972001050200000) .
2. If problem exists in WIF sensor or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in PCM. See DTC P0177: WATER IN FUEL and/or P0178: WATER IN FUEL SENSOR VOLTAGE TOO LOW under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

A/C CLUTCH, AUTO SHUTDOWN (ASD), FUEL HEATER & FUEL PUMP RELAYS

For additional testing of ASD relay or wiring circuit, see DTC P1388: AUTO SHUTDOWN RELAY CONTROL CIRCUIT or P1389: NO ASD RELAY OUTPUT VOLTAGE AT PCM under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article. For additional information on checking wiring circuit for fuel heater relay, see FUEL HEATER under FUEL SYSTEMS. For additional testing of A/C clutch relay wiring circuit, see A/C CLUTCH RELAY CIRCUIT .

1. ASD, fuel pump and fuel heater relays are located in Power Distribution Center (PDC) at driver's side front corner of engine compartment, near battery. (Scheme 54) Turn ignition off. Remove relay to be tested.
2. Using DVOM, check resistance between terminals No. 85 and 86 of relay. (Scheme 58)or (Scheme 59). If resistance is 70-80 ohms, go to next step. If resistance is not 70-80 ohms, replace relay.
3. Check for continuity between terminals No. 30 and 87A. If continuity exists, go to next step. If continuity does not exist, replace relay.
4. Check for continuity between terminals No. 30 and 87. If continuity does not exist, go to next step. If continuity exists, replace relay.
5. Using jumper wires, apply positive battery voltage to relay terminal No. 86 and ground relay terminal No. 85. Check for continuity between relay terminals No. 30 and 87. Continuity should exist. If continuity does not exist, replace relay.

Scheme 58

Scheme 59

FUEL SYSTEMS

Note. For fuel system component locations (Scheme 60)

Scheme 60

Bleeding Air From Fuel System

See BLEEDING AIR FROM FUEL SYSTEM under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES - RAM PICKUP - DIESEL article.

Checking Fuel Delivery

See CHECKING FUEL DELIVERY under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES - RAM PICKUP - DIESEL article.

Fuel Filter/Water Separator

1. A restricted fuel filter/water separator may cause engine starting problems, prevent engine from accelerating, low power or White exhaust smoke.
2. When ignition is first turned on, WATER-IN-FUEL (WIF) warning light should come on for 2 seconds to perform bulb and wiring circuit test and then go off. WIF warning light is located on instrument panel, just below tachometer. If WIF light does not operate properly, go to «WATER-IN-FUEL LIGHT»(ref-97350-S22251591972001050200000) .
3. If WIF warning light stays on, water should be drained from fuel filter/water separator. To drain water from fuel filter/water separator, ensure engine is not running. Place drain pan below drain tube at fuel filter/water separator.
4. Rotate handle on drain valve forward, toward front of vehicle to DRAIN position. Drain valve is located near top of fuel filter/water separator.
5. If no water exists and a clean flow of diesel fuel exists, rotate handle on drain valve back to CLOSE position. Go to next step. If water exists, allow water to drain until clean flow of diesel fuel exists. Rotate handle on drain valve back to CLOSE position. Go to next step.
6. Verify fuel filter/water separator has been serviced according to proper service schedule. See SERVICE & ADJUSTMENT SPECIFICATIONS - RAM PICKUP article. Ensure pre-filter was cleaned when fuel filter/water separator was serviced. Pre-filter is located at bottom of fuel heater on driver's side of engine. No other testing information is available from manufacturer.

Improper fuel injection pump timing may result in low power, excessive smoke and poor fuel economy. To check fuel injection pump timing, see FUEL INJECTION PUMP TIMING under FUEL SYSTEM BASIC DIAGNOSTIC PROCEDURES - RAM PICKUP - DIESEL article.

Overflow Valve

Note. If overflow valve is stuck, DTC P0217: DECREASED ENGINE PERFORMANCE DUE TO ENGINE OVERHEAT CONDITION may set.

1. Clean area around overflow valve and fuel return line at injection pump. Remove overflow valve from pump and banjo fitting. Remove and discard gaskets.
2. Using compressed air with regulated pressure of about 14-16 psi (0.9-1.1 kg/cm 2 ), apply pressure to overflow valve inlet end (injection pump side). If internal check valve releases and air passes through valve, go to next step. If internal check valve does not release and air does not pass through valve, replace valve and gaskets.
3. Reduce air pressure to 10 psi (0.7 kg/cm 2 ) and recheck valve. If valve stays closed, valve is okay. If valve does not stay closed, replace valve and gaskets.

Scheme 61

FUEL CONTROL

Note. A leaking fuel injector or high-pressure fuel line may cause a rough idle, Black smoke, poor engine performance, poor fuel economy and fuel knock. Following procedure is for determining if fuel injector is defective.

Fuel Injector

1. Since a leaking high-pressure fuel line may cause the same symptoms, check for leaking high-pressure fuel line before checking fuel injector. To check for a leaking high-pressure fuel line, start engine and allow engine to idle.
2. Inspect high-pressure fuel lines and connections for signs of fuel leakage by placing cardboard over high-pressure fuel line and connection. Note if leak is being detected by fuel being sprayed onto cardboard. If leak exists, repair leak by tightening high-pressure fuel line nut to 18 ft. lbs. (24 N.m) or replacing high-pressure fuel line as necessary. If high-pressure fuel line is replaced, bleed air from fuel system. See BLEEDING AIR FROM FUEL SYSTEM under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES - RAM PICKUP - DIESEL article.
3. To check for defective fuel injector using scan tool, connect scan tool to Data Link Connector (DLC). Start engine and idle engine. Using scan tool, disable each cylinder and listen for RPM drop. If fuel injector is operating properly, engine idle speed should decrease when each fuel injector is disabled. Repeat procedure on each fuel injector.
4. To check for defective fuel injector without scan tool, start engine and idle engine. Loosen high-pressure fuel line nut at fuel injector and listen for a decrease in engine speed. Tighten high-pressure fuel line nut to 18 ft. lbs. (24 N.m). If fuel injector is operating properly, engine idle speed should decrease when high-pressure fuel line nut is loosened. Repeat procedure on each fuel injector.
5. If engine idle speed does not decrease, fuel injector is defective and should be removed and tested with a diesel fuel injector tester. Replace fuel injector if fuel injector opening (pop) pressure is not about 4500 psi (316 kg/cm 2 ).

Fuel heater receives battery voltage from fuel heater relay. Malfunctioning fuel heater may cause excessive wax build-up in fuel filter/water separator during cold ambient temperatures. Wax build-up may cause hard starting, prevent engine from accelerating, low power, or Blue or White smoke.

Fuel Heater Relay

Fuel heater relay is located in Power Distribution Center (PDC), next to left battery. (Scheme 50) For testing of fuel heater relay, see A/C CLUTCH RELAY, AUTO SHUTDOWN (ASD), FUEL HEATER & FUEL PUMP RELAYS under RELAYS & SOLENOIDS.

Checking Fuel Heater

1. Disconnect 2-pin electrical connector at fuel heater. (Scheme 62) Turn ignition on. Measure voltage at Red/Black wire at fuel heater connector. If 12 volts is present, go to next step. If 12 volts is not present, check for open in Red/Black wire between fuel heater and fuel heater relay. If open is not found, check fuel heater relay. See «A/C CLUTCH RELAY, AUTO SHUTDOWN (ASD), FUEL HEATER & FUEL PUMP RELAYS»(ref-97350-S01063837032001050200000) under RELAYS & SOLENOIDS.
2. Turn ignition off. Check continuity between chassis ground and Black/Tan wire at fuel heater connector. If continuity exists, go to next step. If continuity does not exist, repair open in Black/Tan wire between fuel heater and ground. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Ensure fuel heater 2-pin connector is disconnected. Check for continuity between both fuel heater terminals. Continuity should not be present (open circuit) if fuel temperature is 67-83°F (19-28°C). Continuity should be present (closed circuit) if fuel temperature is 37-53°F (3-12°C). If continuity is not as specified, replace fuel heater assembly. If continuity is as specified, fuel heater assembly is okay. Proceed to «TESTING FUEL HEATER»(ref-97350-S05274421312001051800000).

Scheme 62

WATER-IN-FUEL LIGHT

Note. After completing any repairs, perform TEST VER-2A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

1. Using scan tool, check for stored DTCs. If any DTCs exist, perform appropriate test procedure for stored DTC before proceeding. Turn ignition on with engine off and note operation of WATER-IN-FUEL light. WATER-IN-FUEL light is located on instrument panel, just below the tachometer. If WATER-IN-FUEL light does not stay on, go to next step. If WATER-IN-FUEL light stays on, perform DTC P0178: WATER IN FUEL SENSOR VOLTAGE TOO LOW test under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - RAM TRUCK - DIESEL article.
2. Turn ignition off. Disconnect Water-In-Fuel (WIF) sensor connector. WIF sensor is located at bottom of fuel filter/water separator on driver's side of engine, just behind fuel injection pump. (Scheme 63) Connect jumper wire between terminals "A" (Black/Light Blue wire) and "B" (Dark Green/Red wire) on WIF sensor connector. Turn ignition on with engine off and note operation of WATER-IN-FUEL light. If WATER-IN-FUEL light does not come on, remove jumper wire and go to next step. If WATER-IN-FUEL light comes on, WATER-IN-FUEL light is operating properly at this time. Remove jumper wire and reinstall WIF sensor connector. Test is complete.
3. Turn ignition off. Remove instrument cluster for access to bulb for WATER-IN-FUEL light. See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Inspect bulb for WATER-IN FUEL light on instrument cluster. If bulb for WATER-IN FUEL light is okay, reinstall bulb and go to next step. If bulb for WATER-IN FUEL light is defective, replace bulb. Reinstall instrument cluster if removed.
4. Remove instrument cluster if not previously done. Inspect instrument cluster printed circuit board for damage. If instrument cluster printed circuit board is okay, replace Engine Control Module (ECM). See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. see scheme 21 If instrument cluster printed circuit board is defective, replace instrument cluster printed circuit board as necessary.

Scheme 63

INTAKE MANIFOLD AIR HEATER SYSTEM

See INTAKE MANIFOLD AIR HEATER (IMAH) SYSTEM under AIR INDUCTION SYSTEMS.

MISCELLANEOUS CONTROLS

Note. Although some controlled devices listed here are not technically engine performance components, they can affect driveability if they malfunction.

A/C CLUTCH RELAY

A/C clutch relay is located in Power Distribution Center (PDC) at driver's side front corner of engine compartment, near battery. (Scheme 50) For testing of A/C clutch relay, go to A/C CLUTCH RELAY, AUTO SHUTDOWN (ASD), FUEL HEATER & FUEL PUMP RELAYS under RELAYS & SOLENOIDS. For testing of A/C clutch relay circuit, go to A/C CLUTCH RELAY CIRCUIT.

A/C CLUTCH RELAY CIRCUIT

1. A/C clutch relay is located in Power Distribution Center (PDC) at driver's side front corner of engine compartment, near battery. (Scheme 50) Turn ignition off. Remove A/C clutch relay. Using DVOM, check voltage at terminal No. 30 of A/C clutch relay connector. (Scheme 54) If battery voltage is indicated, go to next step. If battery voltage is not indicated, repair open in Pink/Dark Blue wire between A/C clutch relay and fuse "J" (10-amp) located in PDC.
2. Disconnect A/C compressor clutch connector on A/C compressor. Using DVOM, check for continuity of Dark Blue/Black wire between terminal No. 87 of A/C clutch relay connector and terminal No. 1 of A/C compressor clutch connector. If continuity exists, go to next step. If continuity does not exist, repair open in Dark Blue/Black wire.
3. Using DVOM, check voltage at terminal No. 86 of A/C clutch relay connector. Turn ignition on. If battery voltage is indicated, go to next step. If battery voltage is not indicated, repair open in Dark Blue/White wire between A/C clutch relay and fuse No. 11 (10-amp) located in junction block.
4. Disconnect Powertrain Control Module (PCM) connector C3. (Scheme 50) Using DVOM, check for continuity of Dark Blue/Orange wire between terminal No. 85 of A/C clutch relay connector and terminal No. 1 of PCM connector C3. (Scheme 51) If continuity exists, system is okay at this time. For additional diagnosis, go to «TESTING A/C SYSTEM»(ref-97350-S16061867902001050200000). If continuity does not exist, repair open in Dark Blue/Orange wire.

CHARGING SYSTEM

Note. After completing any repairs, perform TEST VER-3A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

1. Ensure battery is in good condition and fully charged before proceeding with test procedure. Ensure generator drive belt is in good condition and properly adjusted. If generator drive belt is in good condition and properly adjusted, go to next step. If generator drive belt is not in good condition or not properly adjusted, repair as necessary.
2. Start engine and allow engine to idle. Turn on all accessories. Increase engine speed to 2000 RPM for 30 seconds and then return engine to idle. Using scan tool, check for stored DTCs in Powertrain Control Module (PCM). If no charging system DTCs exist, go to next step. If any charging system DTCs exist, perform appropriate DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.
3. Shut engine off. Turn ignition on with engine off. Using scan tool, read battery voltage. Record battery voltage reading. Using DVOM, check voltage between battery terminals. Record battery voltage reading. Compare the 2 battery voltage readings. If difference between the 2 battery voltage readings is one volt or more, go to next step. If difference between the 2 battery voltage readings is less than on volt, test is complete.
4. Ensure ignition is on with engine off. Using scan tool, actuate generator field driver. Using 12-volt test light, check for voltage at terminal No. 1 (Dark Green wire) on 2-wire connector at rear of generator. Test light should cycle on and off every 1.4 seconds. While monitoring test light, wiggle wiring harness and connectors between generator and PCM. PCM is located at passenger's side rear corner of engine compartment. (Scheme 50) If cycling of test light was not interrupted while wiggling wiring harness and connectors, go to next step. If cycling of test light was interrupted while wiggling wiring harness and connectors, repair wiring or connectors as necessary.
5. Stop actuation of generator field driver. Connect DVOM between positive battery terminal on rear of generator and positive battery terminal. Start engine and allow engine to idle. Note voltage reading. If voltage is.4 volt or less, go to next step. If voltage is more than.4 volt, repair high resistance on Black wire and Red wire between generator and the battery.
6. Shut engine off. Turn ignition on with engine off. Using scan tool, check for stored DTCs in PCM. If no charging system DTCs exist, go to next step. If any charging system DTCs exist, perform appropriate DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.
7. Turn ignition off. Connect DVOM between case of generator and negative battery terminal. Start engine and allow engine to idle. Note voltage reading. If voltage is.1 volt or less, go to next step. If voltage is more than.1 volt, repair generator for high resistance between generator case and negative battery terminal.
8. Shut engine off. Turn ignition on with engine off. Using scan tool, read battery voltage. Record battery voltage reading. Turn ignition off. Disconnect PCM connectors. Turn ignition on with engine off. Using DVOM, check voltage at terminal No. 22 (Red/White wire) on PCM connector C1. (Scheme 51) This is the fused B+ circuit to PCM. Record voltage reading. Compare the 2 battery voltage readings. If battery voltage at PCM is within one volt of battery voltage on indicated on scan tool, replace PCM. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article. If battery voltage at PCM is not within one volt of battery voltage on indicated on scan tool, repair Red/White wire between PCM, fuse No. 3 (20-amp) and battery for high resistance. Fuse No. 3 is located in power distribution center at driver's side front corner of engine compartment.

CHECKING PARK/NEUTRAL (P/N) SWITCH (A/T MODELS)

Note. After completing any repairs, perform TEST VER-2A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

1. Apply parking brake. Turn ignition on with engine off. Using scan tool, read park/neutral switch state while moving shift lever through all gear positions. If scan tool does not display P/N and D/R, go to next step. If scan tool displays P/N and D/R, park/neutral switch is functioning properly. Test is complete.
2. Turn ignition off. Place shift lever in Park. Disconnect Powertrain Control Module (PCM) connectors. PCM is located at passenger's side rear corner of engine compartment. (Scheme 50) Using DVOM, check resistance between ground and terminal No. 6 (Black/White wire) on PCM connector C1 while moving shift lever through all gear positions. (Scheme 51) If resistance does not remain less than 5 ohms at all times, go to next step. If resistance remains less than 5 ohms at all times, repair short to ground on Black/White wire between PCM and park/neutral switch. Park/neutral switch is located on driver's side of transmission, just below shift cable lever and contains a 3-pin connector.
3. Disconnect park/neutral switch connector. Park/neutral switch is located on driver's side of transmission, just below shift cable lever and contains a 3-pin connector. Ensure PCM connectors are still disconnected. Using DVOM, check resistance between terminal No. 2 (Black/White wire) on park/neutral switch connector and terminal No. 6 (Black/White wire) on PCM connector C1. (Scheme 64) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Black/White wire between PCM and park/neutral switch.
4. Ensure PCM connectors are still disconnected. Reinstall connector on park/neutral switch. Using DVOM, check resistance between ground and terminal No. 6 (Black/White wire) on PCM connector C1 while moving shift lever through all gear positions and returning to Park. If resistance does not change from less than 5 ohms to more than 5 ohms, replace park/neutral switch. If resistance changes from less than 5 ohms to more than 5 ohms, replace PCM. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article.

Scheme 64