Thursday, 28 May 2026

Perodua Alza 2010 Lama Camshaft Position Sensor Worn Out (Faulty) – Symptoms and Real Driving Experience


Older Perodua Alza models can eventually develop sensor-related problems after many years of use. One of the common hidden issues that can create random and confusing driving problems is a worn out or faulty camshaft position sensor.

The difficult part about this problem is that the car can behave perfectly normal most of the time. Then suddenly, without warning, the engine starts acting strange and loses power badly.

Symptoms of a Faulty Camshaft Position Sensor

1. Sometimes Unable to Start Engine

One of the early warning signs is intermittent starting problems.

Sometimes the engine cranks normally but refuses to start. After waiting for a while, the engine may suddenly start again like nothing happened.

This happens because the ECU struggles to detect the camshaft position correctly. Without proper signal timing, fuel injection and ignition timing become inconsistent.

Because the issue comes and goes randomly, many owners initially suspect:

  • Weak battery

  • Starter problem

  • Fuel pump issue

  • Spark plugs

  • Ignition coil

However the actual cause may be the camshaft position sensor itself.

2. Sudden Power Loss While Driving

This is the more dangerous symptom.

While driving normally on the road, suddenly there is a knocking sensation or jerk from the engine. Immediately after that:

  • Check engine light appears

  • Acceleration fails completely

  • Pressing the gas pedal does almost nothing

  • Engine becomes loud but car does not move faster

  • Vehicle only crawls around 20km/h to 30km/h

It feels like the transmission is failing or the engine has entered emergency mode.

Even at full throttle:

  • RPM may increase

  • Engine noise becomes louder

  • But the vehicle has almost no power

The car still moves slowly, enough to reach roadside or workshop, but normal acceleration disappears completely.

This can be extremely frustrating because after restarting the engine later, the car may return to normal operation again.

Intermittent Nature Makes Diagnosis Difficult

The confusing part is:

  • Most of the time the car drives perfectly fine

  • Symptoms only happen once or twice a week

  • Some days no problem at all

Because of this intermittent behavior, workshops may misdiagnose the issue and replace unnecessary parts first.

Scan Tool Error Codes

Using an OBD scan tool may show:

P0340 – Camshaft Position Sensor Circuit (Angle Cam Sensor)

This is the main indicator that the ECU is detecting abnormal or missing signal from the camshaft position sensor.

The sensor may be:

  • Worn out internally

  • Heat damaged

  • Having unstable signal

  • Intermittently disconnected

  • Affected by deteriorated wiring

U0100 – EFI Communication Failure

This code may appear together with the camshaft sensor problem because unstable engine timing signals can confuse communication between ECU modules.

Sometimes the ECU enters limp mode to protect the engine, resulting in severe power reduction.

Why It Happens More on Older Alza

After many years:

  • Heat from engine bay damages electronics

  • Oil contamination affects sensor readings

  • Wiring becomes brittle

  • Connector terminals oxidize

  • Internal magnetic sensor weakens

The problem usually becomes worse gradually over time.

Common Mistake During Diagnosis

Many owners spend money replacing:

  • Spark plugs

  • Ignition coils

  • Fuel pump

  • Battery

  • Transmission servicing

before discovering the actual culprit is the camshaft position sensor.

Because the issue is random, mechanics may also struggle to reproduce the symptom during inspection.

Recommended Action

If your Alza shows:

  • Random starting issues

  • Sudden limp mode

  • Check engine light

  • P0340 error code

  • Severe loss of acceleration

then the camshaft position sensor and its wiring should be inspected immediately.

In many cases, replacing the sensor solves the problem completely.

Final Thoughts

A faulty camshaft position sensor in an older Perodua Alza can create very serious driving symptoms even though the car appears normal most of the time.

The intermittent nature of the issue makes it difficult to diagnose, but once the symptoms become more frequent, replacement should not be delayed because sudden loss of acceleration during driving can become dangerous, especially on highways or during overtaking.

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