Modern Range Rover models rely on a highly advanced Engine Control Unit, commonly known as the ECU, to manage almost every part of engine operation. The ECU constantly monitors air pressure, throttle position, fuel delivery, ignition timing, sensor signals and communication between different control modules.

When the ECU detects a reading that does not match the expected values, it stores a Diagnostic Trouble Code, or DTC. Codes such as P0069, P0604, P0606, P0607, P0601, P0227 and P0122 can appear when there is a problem with the ECU itself, its software, the wiring, the power supply or one of the connected sensors.

These faults should not be ignored. A Range Rover may continue to drive, but performance can become unreliable. You may notice poor throttle response, reduced power, rough running, increased fuel consumption, warning lights or limp-home mode.

The good news is that accurate testing and professional ECU file services can often identify the real cause and provide a dependable solution.

What Do These Range Rover ECU Fault Codes Mean?

Each fault code points toward a different area of the engine management system. However, a fault code does not always mean that the ECU itself needs replacing. A damaged connector, weak battery, poor earth connection or faulty sensor can create similar symptoms.

P0069 – Manifold Pressure and Barometric Pressure Correlation

The P0069 fault code usually relates to a mismatch between the manifold absolute pressure sensor and the barometric pressure reading.

The ECU uses these values to understand the amount of air entering the engine. If the readings do not agree, the vehicle may experience:

• Reduced engine power
• Poor acceleration
• Uneven idle
• Increased fuel consumption
• Engine warning light
• Limp mode

Possible causes include a faulty MAP sensor, blocked or damaged intake pipe, wiring problems, air leaks, incorrect sensor readings or an ECU calibration issue.

A proper diagnostic process is important because replacing the sensor without checking the wiring and ECU data may not solve the problem.

P0604 – Internal Control Module Random Access Memory Error

P0604 points toward an internal memory problem within the ECU. The control module uses memory to store and process important operating information. If the ECU detects a memory failure, it may struggle to manage engine functions correctly.

This fault can be caused by:

• Low battery voltage
• Voltage spikes
• Poor grounding
• Water damage
• Corrupted ECU software
• Internal ECU hardware failure

A battery test and power supply check should usually be completed before condemning the ECU. In some cases, professional ECU file correction or reprogramming may resolve a software-related issue. In other cases, the module may require specialist repair or replacement.

P0606 – Control Module Processor Fault

The P0606 code is commonly associated with an internal processor fault. Because the processor is responsible for handling the ECU’s calculations, this code can lead to serious drivability problems.

Drivers may experience:

• No-start conditions
• Engine stalling
• Limited performance
• Unstable idle speed
• Delayed throttle response
• Multiple warning lights

A P0606 fault should be investigated carefully. The ECU may be affected by corrupted software, internal memory problems, unstable voltage or a hardware fault.

Professional ECU diagnostics can help determine whether the issue is caused by the file, the module, the wiring or another vehicle system.

P0607 – Control Module Performance

P0607 indicates that the ECU has detected a performance problem within the control module. This does not always mean that the ECU has completely failed. It may be operating outside its expected parameters because of software corruption, voltage instability or an internal fault.

Common symptoms include:

• Intermittent warning lights
• Limp-home mode
• Engine hesitation
• Poor fuel economy
• Difficulty starting
• Random stalling

A complete scan of all vehicle modules is recommended because communication problems elsewhere in the vehicle can sometimes trigger ECU-related codes.

P0601 – Internal Control Module Memory Checksum Error

The P0601 code is associated with a checksum error inside the ECU. A checksum is used to confirm that stored software and calibration data have not been damaged or changed unexpectedly.

This fault may appear after:

• A failed ECU programming session
• Battery voltage dropping during programming
• Software corruption
• An incorrect ECU file
• Internal module damage
• Communication interruption

Attempting to overwrite an ECU file without the correct equipment can make the problem worse. Specialist tools and a verified file are essential when carrying out ECU programming or file correction.

P0227 – Throttle or Accelerator Position Sensor Circuit Low Input

P0227 generally relates to a low signal from a throttle position sensor or accelerator pedal position circuit.

The ECU relies on accurate throttle information to control engine response. If the signal is too low or outside the expected range, the vehicle may enter a safety strategy to prevent unwanted acceleration.

Possible symptoms include:

• Limited throttle response
• Reduced engine power
• Limp mode
• Poor acceleration
• Engine warning light
• Inconsistent pedal response

The fault may be caused by a sensor issue, damaged wiring, a poor connector, water ingress or a fault inside the ECU. Testing the signal voltage and continuity is essential before replacing expensive components.

P0122 – Throttle Position Sensor or Switch A Circuit Low Input

P0122 is another throttle-related fault code. It indicates that the ECU is receiving a signal that is lower than expected from the throttle position sensor circuit.

While P0122 and P0227 can appear similar, the exact cause depends on the Range Rover model, engine type and control system involved.

A professional diagnosis should include:

• Throttle body inspection
• Sensor signal testing
• Wiring and connector checks
• ECU power and earth testing
• Live data analysis
• Throttle adaptation checks

A throttle fault can affect safety and drivability, so the vehicle should not be driven unnecessarily until the problem has been properly assessed.

Why Several ECU Fault Codes May Appear Together

It is not unusual to see several fault codes stored at the same time. One electrical problem can affect multiple systems and create a long list of DTCs.

For example, a weak battery or poor earth connection may cause:

• ECU memory errors
• Processor faults
• Sensor signal problems
• Communication faults
• Random warning lights
• Starting difficulties

This is why replacing parts based only on the fault code can become expensive. The correct approach is to identify the original cause rather than simply clearing the stored codes.