Tech Tips
Use the table below to help determine the cause of the problem symptom. The potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
| Symptom | Suspected Area | See page |
|---|---|---|
| Engine does not crank (does not start) | Starter | - |
| Starter relay | ||
| ECT sensor | - | |
| Difficult to start with cold engine | Engine difficult to start or stalling | |
| Starter signal circuit | ||
| Pre-heating control circuit | ||
| Injector | ||
| Fuel filter | ||
| Compression | ||
| ECM | ||
| Suction control valve | ||
| Fuel pressure sensor | ||
| Diesel throttle body assembly | ||
| EDU (relay) | ||
| Battery deteriorated | - | |
| Fuel with low cetane number used | - | |
| Fuel frozen | - | |
| Air mixed into fuel pipe | - | |
| Difficult to start with warm engine | Engine difficult to start or stalling | |
| Starter signal circuit | ||
| Injector | ||
| Fuel filter | ||
| Compression | ||
| ECM | ||
| Suction control valve | ||
| Fuel pressure sensor | ||
| Diesel throttle body assembly | ||
| EDU (relay) | ||
| Air mixed into fuel pipe | - | |
| Battery deteriorated | - | |
| Engine stalls soon after starting | Engine difficult to start or stalling | |
| Fuel filter | ||
| Injector | ||
| ECM power source circuit | ||
| ECM | ||
| Suction control valve | ||
| Fuel pressure sensor | ||
| Diesel throttle body assembly | ||
| Air mixed into fuel pipe | - | |
| Immobilizer system activated | - | |
| Engine stalling (not including the condition listed above) | Engine difficult to start or stalling | |
| Abnormal initial idling (poor idling) | Rough idling or excessive engine vibration | |
| Fuel filter | ||
| Injector | ||
| ECM | ||
| Suction control valve | ||
| Fuel pressure sensor | ||
| Mass air flow meter deteriorated | - | |
| Fuel with low cetane number used | - | |
| A/Cs signal circuit to ECM open and generators signal circuit to ECM open | - | |
| Low quality fuel | - | |
| High engine idling speed (poor idling) | Rough idling or excessive engine vibration | |
| A/C signal circuit | - | |
| Injector | ||
| Starter signal circuit | ||
| ECM | ||
| Suction control valve | ||
| Fuel pressure sensor | ||
| Speed sensor circuit open | ||
| Accelerator pedal | ||
| Low engine idling speed (poor idling) | Rough idling or excessive engine vibration | |
| A/C signal circuit | - | |
| Injector | ||
| EGR system | ||
| Compression | ||
| Valve clearance | ||
| Fuel line (air bleeding) | ||
| ECM | ||
| Suction control valve | ||
| Fuel pressure sensor | ||
| Diesel throttle body assembly | ||
| Mass air flow meter deteriorated | - | |
| Rough idling (poor idling) | Rough idling or excessive engine vibration | |
| Hunting with hot engine (poor idling) | Injector | |
| ECM power source circuit | ||
| Compression | ||
| Fuel line (air bleeding) | ||
| Valve clearance | ||
| ECM | ||
| Suction control valve | ||
| Fuel pressure sensor | ||
| Diesel throttle body assembly | ||
| Hunting with cold engine (poor idling) | Injector | |
| ECM power source circuit | ||
| Compression | ||
| Fuel line (air bleeding) | ||
| Valve clearance | ||
| ECM | ||
| Suction control valve | ||
| Fuel pressure sensor | ||
| Diesel throttle body assembly | ||
| Fuel with low cetane number used | - | |
| Hesitation / Poor acceleration (poor driveability) | Lack of power or hesitation | |
| Injector | ||
| Fuel filter | ||
| EGR system | ||
| Compression | ||
| ECM | ||
| Suction control valve | ||
| Fuel pressure sensor | ||
| Diesel throttle body assembly | ||
| Accelerator pedal | ||
| Turbocharger system | ||
| Mass air flow meter deteriorated | - | |
| Intake system blockage | - | |
| Exhaust system blockage | - | |
| Knocking (poor driveability) | Engine knocking or rattling | |
| Black smoke emitted (poor driveability) | Black smoke emitted | |
| EGR system | ||
| Injector | ||
| Accumulation in exhaust system | - | |
| Exhaust system blockage | - | |
| White smoke emitted (poor driveability) | EGR system | |
| Injector | ||
| Fuel filter | ||
| ECM | ||
| Suction control valve | ||
| Fuel pressure sensor | ||
| Diesel throttle body assembly | ||
| Pre-heating control circuit | ||
| Low quality fuel | - | |
| Surging / Hunting (poor driveability) | Injector | |
| ECM | ||
| Mass air flow meter deteriorated | - | |
| Suction control valve | ||
| Fuel pressure sensor | ||
| Turbocharger system (VN turbo vane movement is detective) |