Engine Controls - System/component Tests - Diesel Dodge Cab & Chassis R2500

INTRODUCTION

Before testing separate components or systems, perform procedures in BASIC DIAGNOSTIC PROCEDURES - TRUCKS - DIESEL article. Since many computer-controlled and monitored components set a diagnostic trouble code if they malfunction, also perform procedures in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Note. Testing individual components does not isolate short or open circuits. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate shorted or open wiring harness.

INTAKE MANIFOLD AIR HEATER SYSTEM

For testing information on intake manifold air heater system, perform procedures in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

INTERCOOLER

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

TURBOCHARGER

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

Turbocharger Boost Pressure

Turbocharger boost pressure testing information is not available at time of publication.

TURBOCHARGER WASTEGATE

Note. Wastegate adjustment information is not provided by manufacturer.

POWERTRAIN CONTROL MODULE (PCM)

The PCM is located on firewall at passenger's side rear corner of engine compartment. (Scheme 15) The PCM power and ground circuits may be checked by performing specified test. See DTC P0601 in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Scheme 15

Battery Temperature Sensor

1. Battery temperature sensor is snapped into battery tray, below driver's side battery. Disconnect wiring harness at battery temperature sensor.
2. Using ohmmeter, check resistance between electrical terminals on battery temperature sensor. Resistance should be 9000-11,000 ohms at 75-80°F (25-27°C). Replace battery temperature sensor if resistance is not within specification.
3. If problem exists in battery temperature sensor or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Crankshaft Position Sensor

If problem exists in crankshaft position sensor, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See appropriate crankshaft position sensor test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Fuel Heater Temperature Sensor

See FUEL DELIVERY under FUEL SYSTEM.

Intake Manifold Air Temperature Sensor

Intake manifold air temperature sensor is located on top of intake manifold, behind intake manifold air heater. For testing, see DTC P0113: INTAKE AIR TEMPERATURE SENSOR VOLTAGE HIGH test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Transmission Governor Pressure Sensor (A/T Models)

See TRANSMISSION under MISCELLANEOUS CONTROLS.

Transmission Speed Sensor (A/T Models)

See TRANSMISSION under MISCELLANEOUS CONTROLS.

Transmission Temperature Sensor (A/T Models)

See TRANSMISSION under MISCELLANEOUS CONTROLS.

Water-In-Fuel (WIF) Sensor

Water-in-fuel sensor is located in bottom of fuel filter/water separator. Testing information not available from manufacturer.

Brake Switch

1. Remove lower panel for access to brake switch. Brake switch is located on bracket, near top of brake pedal. Disconnect electrical connector from brake switch. Pull plunger on brake switch fully outward. (Scheme 16)
2. Using ohmmeter, check for continuity between terminals No. 5 and 6 on brake switch. (Scheme 16) Continuity should exist. If continuity exists, go to next step. If continuity does not exist, replace brake switch.
3. Push plunger on brake switch fully inward. Using ohmmeter, check for continuity between terminals No. 1 and 2, and 3 and 4 on brake switch. (Scheme 16) Continuity should exist. If continuity does not exist, replace brake switch.

Scheme 16

(A/T Models)

See TRANSMISSION under MISCELLANEOUS CONTROLS.

Transmission Overdrive Switch (A/T Models)

See TRANSMISSION under MISCELLANEOUS CONTROLS.

A/C Clutch Relay

A/C clutch relay may also be referred to as A/C compressor clutch relay. A/C clutch relay is located in power distribution center at driver's side front corner of engine compartment, near battery. If problem exists in A/C clutch relay or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See DTC P0645 in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Auto Shutdown (ASD) Relay

ASD relay is located in power distribution center at driver's side front corner of engine compartment, near battery. If problem exists in ASD relay or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Fuel Heater Relay

1. Fuel heater relay is located in Power Distribution Center (PDC) next to left battery. Refer to PDC lid for relay location. Remove relay and note terminal identification on relay. (Scheme 17)
2. Using ohmmeter, check resistance between terminals No. 85 and 86 on relay. Resistance should be 70-80 ohms. If resistance is within specification, go to next step. If resistance is not within specification, replace relay.
3. Using ohmmeter, ensure continuity exists between terminals No. 30 and 87A on relay. If continuity exists, go to next step. If no continuity exists, replace relay.
4. Using ohmmeter, ensure no continuity exists between terminals No. 30 and 87 on relay. If no continuity exists, go to next step. If continuity exists, replace relay.
5. Using jumper wires, connect terminal No. 85 to negative side of 12-volt power source and terminal No. 86 to positive side of 12-volt power source. Using ohmmeter, ensure no continuity now exists between terminals No. 30 and 87A on relay. If no continuity exists, go to next step. If continuity exists, replace relay. CAUTION: DO NOT allow ohmmeter leads to contact terminals No. 85 and 86 on relay when checking resistance.
6. Using ohmmeter, ensure continuity now exists between terminals No. 30 and 87 on relay. If continuity exists, disconnect jumper wires from relay. If no continuity exists, replace relay.

Note. For additional information on checking wiring circuit for fuel heater relay, see TEST NTC-1: NO TROUBLE CODE TEST MENU and TEST NS-SEL: NO START TEST SELECTION in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Scheme 17

Intake Manifold Air Heater Relays

1. Intake manifold air heater relays may also be referred to as intake air heater relays. Intake manifold air heater relays are mounted on inner wheelwell, below driver's side battery. (Scheme 18)
2. Disconnect negative battery cables. Note location of wiring on intake manifold air heater relays for reassembly reference. Disconnect all electrical connectors and cables from intake manifold air heater relays.
3. Connect ohmmeter between large terminals on intake manifold air heater relay to check for continuity. Using jumper wires, momentarily apply battery voltage to relay trigger wire terminals (small wire terminals) at base of intake manifold air heater relay. (Scheme 18) Polarity is not important.
4. Intake manifold air heater relay should click and ohmmeter should indicate continuity between large terminals when battery voltage is applied to relay trigger wire terminals. If intake manifold air heater relay operation is not as specified, replace intake manifold air heater relay with bracket. Test remaining intake manifold air heater relay. Remove ohmmeter. Reconnect all electrical connectors and negative battery cables.

Note. For additional information on checking wiring circuit for intake manifold air heater relay, see DTC P0380: INTAKE AIR HEATER RELAY NO. 1 CONTROL CIRCUIT and DTC P0382: INTAKE AIR HEATER RELAY NO. 2 CONTROL CIRCUIT tests in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Scheme 18

Transmission Relay (A/T Models)

Transmission relay may be referred to as transmission control relay or transmission 12-volt supply relay. Transmission relay is located in power distribution center at driver's side front corner of engine compartment, near battery. If problem exists in transmission relay or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See DTC P1765: TRANSMISSION 12-VOLT SUPPLY RELAY CONTROL CIRCUIT test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Transmission Overdrive Solenoid (A/T Models)

See TRANSMISSION under MISCELLANEOUS CONTROLS.

Transmission Torque Converter Clutch Solenoid (A/T Models)

See TRANSMISSION under MISCELLANEOUS CONTROLS.

Scheme 19

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. WATER-IN-FUEL (WIF) warning light is located on instrument panel, just below tachometer.
3. If WATER-IN-FUEL (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 - TRUCKS 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.

Fuel Heater

1. 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.
2. Disconnect electrical connector at fuel heater. Fuel heater is located in top of fuel filter housing. Using ohmmeter, check resistance between electrical terminals on fuel heater.
3. Resistance should be about one ohm when fuel is cold, and about 1000 ohms when fuel is warm. Replace fuel heater if resistance is not within specification.

Note. Fuel heater receives battery voltage from fuel heater relay. Fuel heater relay is located in Power Distribution Center (PDC), next to left battery. Refer to PDC lid for relay location. For testing of fuel heater relay, see RELAYS under RELAYS & SOLENOIDS. Consult wiring diagram for wiring circuit testing. See appropriate wiring diagram in WIRING DIAGRAMS article.

Fuel Transfer Pump Preliminary Inspection

1. Check for restricted or leaking fuel supply line to fuel transfer pump or fuel return line located on driver's side of engine. Repair fuel supply line or fuel return line if restricted or leaking.
2. Check for fuel leaking from weep hole on housing of fuel transfer pump. Replace fuel transfer pump if fuel is leaking from weep hole. Check fuel transfer pump for output pressure, pressure drop, supply restriction, and air leaks.

Fuel Transfer Pump Output Pressure

Note. Separate pressure tests are necessary because transfer pump operates at 2 pressure cycles, depending on whether engine is running or cranking.

1. Remove 2 existing filter plug fittings at top of fuel filter housing. Install 2 spring-loaded one-way check valve fittings at inlet and outlet port. Install Fuel Pressure Test Gauge (6828) to inlet port fitting. Prevent engine from starting by removing fuel injection pump relay. Relay is located in Power Distribution Center (PDC) next to left battery. Relay location is notated on PDC lid.
2. Crank engine while observing fuel pressure test gauge. Fuel pressure should be 5-7 psi (0.35-0.49 kg/cm 2 ). Reinstall fuel system relay to PDC. Start engine. Fuel pressure should be minimum of 10 psi (0.7 kg/cm 2 ). Because fuel injection pump relay was removed, a Diagnostic Trouble Code (DTC) may have been set. Use DRB scan tool to erase DTC. Go to «PRESSURE DROP»(/dodge/cab-chassis-r2500/1996-2002/remont/testing-diagnostics/#engine-controls-systemcomponent-tests-diesel__pressure-drop) test.

Pressure Drop

Turn engine off. Remove Fuel Pressure Test Gauge (6828) from inlet port and attach to outlet port. Start engine and note fuel pressure. Pressure should not be more than 5 psi (0.35 kg/cm 2 ) less than inlet port pressure in Fuel Transfer Pump Outlet Pressure test. See FUEL TRANSFER PUMP OUTPUT PRESSURE test. If fuel pressure is not to specification, replace fuel filter. Go to FUEL SUPPLY RESTRICTION test.

Fuel Supply Restriction

Note. Following test requires use of DRB scan tool and Periphal Expansion Port (PEP) module. Ensure transfer pump pressure is okay before performing following test.

1. Disconnect fuel supply line quick-connect fitting at left rear side of engine compartment. After disconnecting fuel line, plastic clip will remain attached to metal fuel line at engine. Remove clip from metal line. Snap clip into fuel supply hose. Install Rubber Adapter Hose (6631) into ends of disconnected fuel supply line.
2. Install transducer from PEP module to brass "T" fitting on rubber adapter hose. Connect DRB scan tool to transducer. Start engine and record vacuum reading with engine speed at wide open throttle.
3. If vacuum reading is less than 6 in. Hg, check for restriction in fuel supply line or fuel tank module. Repair fuel supply line or module for restrictions as necessary. Also check fuel pump inlet filter at bottom of module for obstructions. Go to «AIR LEAK IN FUEL SUPPLY SIDE»(/dodge/cab-chassis-r2500/1996-2002/remont/testing-diagnostics/#engine-controls-systemcomponent-tests-diesel__air-leak-in-fuel-supply-line) test.

Air Leak In Fuel Supply Line

Note. Following test requires use of a 3-foot section of 1/4" I.D. clear tubing and 1/8" fitting.

1. Locate 2 test port plug fittings at top of fuel filter housing. Clean fitting area. Remove test port fitting at fuel inlet side of housing toward rear of filter housing. Install 1/8" fitting with 1/4" O.D. nipple in place of test port. Clamp clear tubing to fitting nipple. Place other end of hose into clear container.
2. To put fuel transfer pump into a 25 second run mode, turn ignition switch to CRANK position, then release back to RUN position without starting engine. Wait for air to purge from empty hose before checking whether air bubbles are present. If bubbles are present, check for leaks in supply line to fuel tank. If supply line is not leaking, remove fuel tank module. Remove filter at bottom of module. Check for leaks between supply nipple at top of module and filter opening at bottom of module. Replace module as necessary.

Overflow Valve

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. Using blow gun 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.
2. 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.

Fuel Injection Pump

1. Ensure fuel transfer pump output pressure is within specification before condemning fuel injection pump. See «FUEL TRANSFER PUMP OUTPUT PRESSURE»(/dodge/cab-chassis-r2500/1996-2002/remont/testing-diagnostics/#engine-controls-systemcomponent-tests-diesel__fuel-transfer-pump-output-pressure). No mechanical adjustments are needed for fuel injection timing. All timing and fuel adjustments are made by Engine Control Module (ECM). If a DTC has been stored indicating an ENGINE SYNC ERROR or STATIC TIMING ERROR, remove plastic access cover, injection pump nut and washer.
2. Locate keyway behind washer. Ensure keyway aligning fuel injection pump shaft to injection pump gear is in correct position and pump gear has not slipped on pump shaft. Remove timing gear cover to access timing gears. See 5.9L (24-VALVE) 6-CYLINDER DIESEL article in ENGINES. Use a "T" puller and separate injection pump gear from pump shaft. Ensure keyway is installed with arrow toward rear of pump. NOTE: Pump timing is calibrated to pump keyway. Ensure 3-digit number on pump keyway matches 3-digit number on fuel injection pump data plate on side of injection pump. (Scheme 20)
3. Ensure timing marks on crank, camshaft and pump align. Align gears as necessary. After repair, erase DTC.

Scheme 20

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 FUEL LINE BLEEDING under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article.
3. To check for defective fuel injector, start 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).
4. 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 ).

Intake Manifold Air Heater Preheat/Postheat Cycle

For testing information on intake manifold air heater system, see DTC P0380: INTAKE AIR HEATER RELAY NO. 1 CONTROL CIRCUIT and DTC P0382: INTAKE AIR HEATER RELAY NO. 2 CONTROL CIRCUIT tests in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

MISCELLANEOUS CONTROLS

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

Park/Neutral Switch (A/T Models)

Park/neutral switch is mounted on transmission case, near shift lever and contains a 3-pin connector. If problem exists in park/neutral switch or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See DTC P1899: P/N SWITCH STUCK IN PARK OR IN GEAR test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Transmission governor pressure sensor is located on transmission valve body. If problem exists in transmission governor pressure sensor or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See appropriate governor pressure sensor test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Transmission overdrive solenoid may also be referred to as overdrive solenoid or 3-4 solenoid. Transmission overdrive solenoid is located transmission valve body. If problem exists in transmission overdrive solenoid or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See DTC P1740: TCC OR O/D SOLENOID PERFORMANCE test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

See RELAYS under RELAYS & SOLENOIDS .

Transmission speed sensor may also be referred to as transmission output shaft speed sensor. Transmission speed sensor is located on overdrive case at rear of transmission. Transmission speed sensor contains a 2-pin connector with a Dark Blue/Black wire and a Light Green/Black wire. If problem exists in transmission speed sensor or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See DTC P0720: LOW OUTPUT SPEED SENSOR RPM, ABOVE 15 MPH test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

Transmission temperature sensor is incorporated into governor pressure sensor on transmission valve body. If problem exists in transmission temperature sensor or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See appropriate transmission temperature sensor test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

The transmission Torque Converter Clutch (TCC) solenoid is located on transmission valve body. If problem exists in TCC solenoid or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in Powertrain Control Module (PCM). See DTC P0743: TORQUE CONVERTER CLUTCH SOLENOID/TRANSMISSION RELAY CIRCUIT test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.

See also:
• FUEL DELIVERY
• PRESSURE DROP
• FUEL TRANSFER PUMP OUTPUT PRESSURE
• FUEL SUPPLY RESTRICTION
• AIR LEAK IN FUEL SUPPLY SIDE