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

Turbocharger Boost Pressure Test

Note. Ensure 2 fuel pressure test gauges of the same calibration are available for test. Connect both gauges to a common pressure source and compare gauge readings. If readings are not the same, gauges can still be used. Note and record pressure differences between gauges.

1. Remove 3/4" pipe fitting at rear of intake manifold. (Scheme 43) Do not remove pipe fitting behind MAP sensor, this is a coolant passage plug. Adapt one fuel pressure gauge to opening in intake manifold.
2. Loosen clamp attaching signal line to 1/8" brass fitting at front of turbocharger, near oil filter. Remove brass fitting and adapt second fuel pressure gauge to turbocharger using a "T" fitting. Attach signal line to "T" fitting.
3. Run engine under full load to approximately 1600 RPM and monitor both fuel pressure gauges. Maximum pressure is 16.2-19.7 psi (33-40 in. Hg). If gauges are not within 3 psi (6 in. Hg) of each other, check for restricted or damaged intercooler or piping.
4. Wastegate should open at no more than 19 psi (38.7 in. Hg) at wide-open throttle under full load. If wastegate does not open at specified pressure, check wastegate adjustment. See «TURBOCHARGER WASTEGATE»(ref-97350-S38433851612001050200000).

Scheme 43

Brake Switch Test

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 44)
2. Check for continuity between terminals No. 1 and 2 on brake switch. (Scheme 44) Continuity should exist. If continuity exists, go to next step. If continuity does not exist, replace brake switch. See appropriate REMOVAL, OVERHAUL & INSTALLATION article.
3. Push plunger on brake switch fully inward. Check for continuity between terminals No. 3 and 4, and 5 and 6 on brake switch. (Scheme 44) Continuity should not exist. If continuity does exist, replace brake switch.

Scheme 44

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. For diagnosing fuel transfer pump output pressure, pressure drop, supply restriction, and air leaks, see FUEL TRANSFER PUMP under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES - RAM PICKUP - DIESEL article.

Testing Fuel Heater

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

1. Turn ignition on. Remove fuel heater relay from Power Distribution Center (PDC). see scheme 11 Reinstall fuel heater relay and listen for click sound. If relay clicks, go to next step. If relay does not click, go to step 6.
2. Turn ignition off. Ensure fuel heater relay is removed from PDC. Disconnect fuel heater 2-pin connector. see scheme 19 Using DVOM, check resistance between ground and terminal "A" (Black/Tan wire) of fuel heater connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Tan wire between fuel heater and ground connection located at left rear of engine.
3. Ensure fuel heater 2-pin connector is disconnected. Ensure fuel heater temperature is less than 40°F (5°C). Check for continuity between both fuel heater terminals (component side). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, go to «CHECKING INTAKE AIR HEATER NO. 1»(ref-97350-S03609058372001050200000) under INTAKE MANIFOLD AIR HEATER (IMAH) SYSTEM under AIR INDUCTION SYSTEMS.
4. Using DVOM, check resistance of Red/Black wire between terminal "B" of fuel heater connector and terminal No. 87 of fuel heater relay connector. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in Red/Black wire.
5. Check voltage at terminal No. 30 (Red/Tan wire) at fuel heater relay. If voltage is 10 volts or more, replace fuel heater. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article. If voltage is less than 10 volts, repair open in Red/Tan wire between fuse No. 7 (40-amp) and fuel heater relay.
6. Turn ignition off. Ensure fuel heater relay is removed from PDC. Using DVOM, check resistance between ground and terminal No. 85 (Black wire) at fuel heater relay connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black wire between fuel heater relay and ground connection located on left inner fender.
7. Turn ignition on. Check voltage at terminal No. 86 (Dark Blue/White wire) at fuel heater relay. If voltage is 10 volts or more, replace fuel heater relay. If voltage is less than 10 volts, repair open in Dark Blue/White wire between fuse No. 11 (10-amp) located in junction block at end of instrument panel and fuel heater relay.

A/C SYSTEM TEST

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. Using scan tool, check for stored DTCs. If DTC P0645 does not exist, go to next step. If DTC P0645 exists, perform DTC P0645: A/C CLUTCH RELAY CIRCUIT test under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.
2. Turn ignition on with engine off. Using scan tool, monitor A/C REQUEST state. Turn A/C switch to ON position and place A/C fan switch in HIGH position while noting A/C REQUEST state. If A/C REQUEST state changes, go to next step. If A/C REQUEST state does not change, go to step 9.
3. Using scan tool, monitor A/C SELECT state. Turn A/C switch to ON and OFF positions several times while noting A/C SELECT state. If A/C SELECT state changes, go to next step. If A/C SELECT state does not change, repair open on A/C select circuit. A/C select circuit is the Light Green/White wire that goes from terminal No. 23 on Powertrain Control Module (PCM) connector C3 to terminal No. 2 on A/C heater control assembly. see scheme 7and (Scheme 45). PCM is located at passenger's side rear corner of engine compartment. see scheme 6
4. Ensure ignition is on with engine off. Using scan tool, actuate A/C clutch relay and note operation of A/C clutch on A/C compressor. If A/C clutch does not engage when A/C clutch relay is actuated, go to next step. If A/C clutch engages when A/C clutch relay is actuated, A/C clutch is operating properly at this time. Test is complete.
5. Stop actuation of A/C clutch relay. Turn ignition off. Disconnect A/C clutch connector at A/C compressor. Turn ignition on with engine off. Using scan tool, actuate A/C clutch relay. Connect test light between terminals No. 1 (Dark Blue/Black wire) and No. 2 (Black/White wire) on A/C clutch connector. If test light does not blink, go to next step. If test light blinks, replace electrical coil on A/C compressor for A/C clutch. See appropriate article in AIR CONDITIONING & HEATING.
6. Turn ignition off. Remove A/C clutch relay. A/C clutch relay is located in power distribution center at driver's side front corner of engine compartment. see scheme 6 Note cavities in power distribution center for A/C clutch relay. see scheme 11 Ensure A/C clutch connector is still disconnected at A/C compressor. Using DVOM, check resistance of Dark Blue/Black wire between cavity No. 87 in power distribution center for A/C clutch relay and terminal No. 1 on A/C clutch connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Dark Blue/Black wire between A/C clutch connector and cavity No. 87 in power distribution center for A/C clutch relay.
7. Ensure A/C clutch relay is still removed from power distribution center. Using 12-volt test light, check for voltage at cavity No. 30 (Pink/Dark Blue wire) in power distribution center for A/C clutch relay. see scheme 11 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 and cavity No. 30 (Pink/Dark Blue wire) in power distribution center for A/C clutch relay. It may be necessary to check fuse "J" (10-amp). Fuse "J" is located in power distribution center.
8. Using DVOM, check resistance between ground and terminal No. 2 (Black/White wire) on A/C clutch connector. If resistance is less than 5 ohms, replace A/C clutch relay. If resistance is 5 ohms or more, repair open on Black/White wire between A/C clutch connector and ground connection. Ground connection is located on cylinder block, just below fuel transfer pump.
9. Check operation of high pressure cut-off switch. See appropriate article in AIR CONDITIONING & HEATING. If high pressure cut-off switch operates properly, go to next step. If high pressure cut-off switch does not operate properly, replace high pressure cut-off switch.
10. Check operation of low pressure cut-off switch. See appropriate article in AIR CONDITIONING & HEATING. If low pressure cut-off switch operates properly, go to next step. If low pressure cut-off switch does not operate properly, replace low pressure cut-off switch.
11. Ensure A/C system is properly charged. If A/C system is properly charged, go to next step. If A/C system is not properly charged, recharge A/C system as necessary using approved equipment.
12. It is assumed that an open exists on A/C request circuit. A/C request circuit is the Brown wire that goes from terminal No. 22 on PCM connector C3 to terminal No. 1 on low pressure cut-off switch, and then from terminal No. 2 on low pressure cut-off switch to terminal No. 2 on high pressure cut-off switch as a Dark Blue wire, and then goes from terminal No. 1 on high pressure cut-off switch to terminal No. 2 on A/C heater control assembly on a Light Green/White wire.

Scheme 45