Engine Controls - Tests W/o Codes - Diesel Dodge Cab & Chassis R3500

INTRODUCTION

Before using this article, perform steps in BASIC DIAGNOSTIC PROCEDURES - TRUCKS - DIESEL and SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS articles. Use this article to diagnose driveability problems existing when a hard Diagnostic Trouble Code (DTC) is not present.

Note. Some driveability problems may have been corrected by manufacturer with a revised Powertrain Control Module (PCM). Check with manufacturer for latest PCM application.

Symptom checks direct the technician to malfunctioning component(s) for further diagnosis. A symptom should lead to a specific component, system test or adjustment.

Use TEST PROCEDURES under INTERMITTENTS to locate driveability problems that DO NOT occur when the vehicle is being tested. These test procedures should also be used if an intermittent (soft) DTC was present, but no problem is found during self-diagnostic testing.

Note. For specific testing procedures, see SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article. For specifications, see ON-VEHICLE ADJUSTMENTS - TRUCKS - DIESEL or SERVICE & ADJUSTMENT SPECIFICATIONS - TRUCKS article.

SYMPTOM DIAGNOSIS

Symptom checks cannot be used properly unless the problem occurs while the vehicle is being tested. To reduce diagnostic time, ensure steps in BASIC DIAGNOSTIC PROCEDURES - TRUCKS - DIESEL and SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS articles were performed before diagnosing a symptom. Symptoms available for diagnosis are as follows

1. Black Exhaust Smoke
2. White Exhaust Smoke
3. Blue Exhaust Smoke

BLACK EXHAUST SMOKE

1. Air filter dirty or plugged.
2. Air intake system restricted.
3. Exhaust system restriction is above specification.
4. Poor fuel quality.
5. Fuel injection pump malfunctioning.
6. Fuel injector malfunctioning or leaking.
7. Fuel return system restricted.
8. Intake manifold restricted.
9. Turbocharger problem.

WHITE EXHAUST SMOKE

1. Air in fuel system.
2. Coolant leak into combustion chamber.
3. Block heater malfunction in cold weather.
4. Clogged or defective fuel filter.
5. Poor fuel quality.
6. Fuel injector malfunctioning or loose.
7. Restricted or blocked fuel injection or supply lines.
8. Intake/exhaust valves not adjusted properly (tight).
9. Intake heaters malfunctioning.
10. Internal engine damage.

BLUE EXHAUST SMOKE

1. Air filter dirty or plugged.
2. Air intake system restricted.
3. Air leak in intake between turbocharger and intake manifold.
4. Restricted exhaust.
5. Restricted turbocharger drain tube.
6. Crankcase ventilation plugged.
7. Valve stems, guides or seals worn or defective.
8. Piston rings improperly gapped, worn or broken.
9. Internal engine wear.
10. Turbocharger fialure.

INTERMITTENT PROBLEM DIAGNOSIS

Intermittent fault testing requires duplicating circuit or component failure to identify problem. These procedures may lead to PCM setting a Diagnostic Trouble Code (DTC) which may help in diagnosis.

If problem vehicle does not produce DTCs, monitor voltage or resistance values using a Digital Volt-Ohmmeter (DVOM) while attempting to reproduce conditions causing intermittent fault. A status change on DVOM indicates a fault has been located.

Use a DVOM to pinpoint faults. When monitoring voltage, ensure ignition switch is in ON position or engine is running. Ensure ignition switch is in OFF position or negative battery cable is disconnected when monitoring circuit resistance. Status changes on DVOM during test procedures indicate area of fault.

Intermittent Simulation

To reproduce conditions creating an intermittent fault, use following methods

1. Lightly vibrate component.
2. Heat component.
3. Wiggle or bend wiring harness.
4. Spray component with water.
5. Remove/apply vacuum source.

Monitor circuit/component voltage or resistance while simulating intermittent. If engine is running, monitor for diagnostic trouble codes. Use test results to identify a faulty component or circuit.

See also:
• TEST PROCEDURES