Nissan Almera: simple faults on a simple car, and where the fuel consumption hides

The Almera was designed as an inexpensive, straightforward saloon, and in diagnostics that simplicity is an advantage. There is almost nothing exotic here, so the list of typical faults is short and repetitive.

1. Ignition coils and plugs

Codes P0300–P0304, P0351–P0354.

Symptoms: rough running when cold, jerking under load, idle vibration.

Individual coils are convenient because the code names the cylinder directly. The most reliable check is swapping coils between cylinders: if the code follows the coil, the coil is at fault. Order in misfire troubleshooting.

2. Airflow meter and vacuum leaks

Code P0171, long-term trim above +15 %.

Two different scenarios people confuse:

• Trim worse at idle, normal at high RPM — a vacuum leak. Look for splits in hoses and vacuum lines.
• Trim rising with load — a contaminated airflow meter.

The distinction by operating state is set out in the lean mixture guide, and the sensor itself in the airflow meter guide.

3. The thermostat — the main cause of consumption with no lamp

The most important item in this article.

P0128 means the engine never reaches its designed temperature. The module treats it as insufficiently warm and holds an enriched mixture permanently. Consumption rises 10–20 %, the heater is weak, and the lamp may never light at all.

The check takes five minutes: start the engine cold and watch temperature in live data. Normal is a steady climb to 185–205 °F in 5–10 minutes.

A lying temperature sensor produces the same effect — covered in the sensor guide.

4. Oxygen sensors

Codes P0130–P0141, and at higher mileage P0420.

An aged sensor responds slowly, the module constantly overshoots, and consumption rises. There may be no codes for years.

The check is signal oscillation speed in live data; covered in the oxygen sensor guide.

Separately: two heater codes at once (P0135 + P0141) almost always mean one fuse, not two sensors — see its own article.

5. Idle valve and throttle body

Hunting idle, stalling at lights. Code P0505 or no code.

Cleaning helps, but adaptation afterwards is mandatory or the idle gets worse still. Mechanics in the P0505 guide.

6. Wheel speed sensors

Codes C0035–C0050, the ABS lamp, sometimes with P0500.

On budget cars the harnesses to the wheel sensors chafe through faster than the sensors themselves fail. Inspect the wire at its flex point rather than replacing the part first. Covered in the ABS sensor guide.

A fifteen-minute check sequence

1. Read all codes, pending included.
2. Warm-up temperature — the cheapest and most common consumption cause.
3. Long-term trim at idle and at 2500 RPM.
4. Per-cylinder misfire counters.
5. Upstream oxygen sensor signal.
6. ABS codes separately.
7. Voltage: 12.4–12.7 V overnight, 13.8–14.4 V running.

In short

• Coils are verified by swapping between cylinders — free and conclusive.
• The thermostat is the main cause of raised consumption with no warning lamp.
• The operating state where trim is worst separates a leak from the airflow meter.
• Two oxygen sensor heater codes means one fuse.
• ABS codes more often mean a chafed wire than a dead sensor.

Download the app — temperature, trims, and codes across every system are read with an ELM327 adapter over Bluetooth SPP on Android.