Lexus NX: Problem Symptoms Table
PROBLEM SYMPTOMS TABLE
HINT:
- Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, 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.
- Inspect the fuses and relays related to this system before inspecting the suspected areas below.
| Symptom | Suspected Area | Link |
|---|---|---|
| Engine does not crank (Does not start) | Immobiliser system | |
| Hybrid control system | | |
| VC output circuit (ECM 5 V output) | | |
| No initial combustion (Does not start) | ECM power source circuit | |
| VC output circuit (ECM 5 V output) | | |
| Crankshaft position sensor | | |
| Camshaft position sensor | | |
| Ignition system | | |
| EGR valve assembly | | |
| Fuel injector circuit | | |
| Valve timing | | |
| Fuel pump control circuit | | |
| ECM | | |
| Engine cranks normally but difficult to start | Engine coolant temperature sensor | |
| Ignition system | | |
| Fuel injector assembly | | |
| Compression | | |
| Fuel injector circuit | | |
| EGR valve assembly | | |
| Intake system | | |
| Throttle body with motor assembly | | |
| ECM power source circuit | | |
| Fuel pump control circuit | | |
| Incomplete intermittent combustion occurs (Does not start) | Fuel line | - |
| Ignition system | | |
| Fuel injector assembly | | |
| EGR valve assembly | | |
| Crankshaft position sensor | | |
| Valve timing | | |
| Fuel pump control circuit | | |
| High engine speed | Throttle body with motor assembly | |
| Engine coolant temperature sensor | | |
| PCV valve and hose | | |
| ECM power source circuit | | |
| Low engine speed (Poor idle) | Throttle body with motor assembly | |
| Intake system | | |
| PCV valve and hose | | |
| Fuel pump control circuit | | |
| Rough idle | Rough Idling | |
| Compression (engine mechanical) | | |
| Air fuel ratio sensor | | |
| Heated oxygen sensor | | |
| Mass air flow meter sub-assembly | | |
| Ignition system | | |
| Fuel line | - | |
| Valve timing | | |
| Intake system | | |
| PCV valve and hose | | |
| Fuel pump control circuit | | |
| EGR valve assembly | | |
| Hunting (Poor idle) | PCV valve and hose | |
| Mass air flow meter sub-assembly | | |
| Air fuel ratio sensor | | |
| Drive Start Control System | | |
| Hesitation/Poor acceleration (Poor driveability) | Fuel line | - |
| Valve timing | | |
| Mass air flow meter sub-assembly | | |
| Throttle body with motor assembly | | |
| Knock control sensor | | |
| Fuel pump control circuit | | |
| Brake override system | | |
| Drive Start Control System | | |
| Surging (Poor driveability) | Fuel line | - |
| Ignition system | | |
| Fuel injector assembly | | |
| Fuel pump control circuit | | |
| Engine stalls soon after starting | Mass air flow meter sub-assembly | |
| Intake system | | |
| EGR valve assembly | | |
| Fuel line | - | |
| Unable/difficult to refuel | Fuel system (canister, refueling valve, roll over valve, fuel tank, etc.) | - |
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