Do you have a Mercedes CLA with 234,000 km and have found yourself with the engine failure light on ? Did the diagnostic check show the codes P022664 , P02023A and P02033A ? In this guide you will find a complete analysis to understand what these errors mean , which parts to check , and above all what to do to solve the problem without wasting time or money unnecessarily.
🚨 Symptoms: How the problem manifests itself
With the above codes, you may notice the following behaviors of your car:
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Engine light on steady
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Engine entering “emergency” or recovery mode
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Erratic acceleration , “gaps” or delays in response
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Vibrations or 3-cylinder operation
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Increased consumption or difficulty starting
📋 Error Code Decoding
🔸 P022664 – Electronic accelerator pedal: implausible signal
This code indicates that the control unit does not correctly recognize the signal sent by the accelerator pedal . Causes may include:
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Internal sensor faulty
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Dirty or oxidized connector
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Broken or faulty wiring
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Inconsistency between the two pedal potentiometers (modern electronic pedals use two sensors for safety)
👉 Consequences : slow response to the pedal, failure to accelerate, engine in protection.
🔸 P02023A – Cylinder 3 Injector: Electrical Fault or Open Circuit
This error indicates that the control unit is receiving an incorrect or interrupted signal from the cylinder 3 injector.
🔸 P02033A – Cylinder 2 Injector: Electrical Fault or Open Circuit
Error identical to the previous one, but related to cylinder 2 .
👉 Common causes for both :
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Electrically damaged injectors
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Abnormal resistance in internal solenoids
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Oxidized or loose connectors
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Damaged or interrupted wiring between injectors and engine control unit (ECU)
👉 Consequences : irregular engine operation, vibrations, reduced performance.
🔬 What to check and how to proceed
✅ 1. Visual inspection and cleaning of connectors
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Carefully disconnect the injector and accelerator pedal connectors.
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Use an electrical contact cleaner (such as CRC or equivalent)
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Check for oxidation, dirt or liquids
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Check that the pins are not bent or worn.
✅ 2. Injector Test (Electric)
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Measures the ohmic resistance of the injectors (indicative values 0.5–1.5 Ohm, but it depends on the model)
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If one or more values are incorrect, it is likely that the injector needs to be replaced.
✅ 3. Using a diesel injector additive
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Add a specific additive to the tank to clean the injection system
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Choose a professional product and use it with the tank half full.
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Repeat for two fulls if necessary.
✅ 4. Accelerator pedal control
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If the P022664 code persists even after cleaning, it is likely that the sensor built into the pedal is faulty.
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Replacing the pedal solves 90% of cases, provided the electrical system is intact
🛠 When is it necessary to replace components?
Replace injectors if:
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Codes P02023A and P02033A do not disappear after cleaning
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The engine continues to run on 3 cylinders
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Injectors show abnormal values on electrical test
Replace accelerator pedal if:
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Code P022664 returns after reset
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You have ruled out wiring, oxides and connector problems
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The car does not respond well to acceleration
🔁 After the procedure: cancellation and proof
After having carried out the checks and any replacements:
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Clear fault codes with diagnostic tool
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Do a test drive of at least 10–15 km
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If the codes do not return , the problem has been resolved.
⚠️ Final advice
With 234,000 km , these problems are not uncommon. Modern diesel systems, especially Common Rail with complex electronic control , require precise maintenance. It is better to intervene immediately to avoid damage to the control unit or worsening performance.
❓Frequently Asked Questions
Can I drive with these errors active?
Not recommended. The ECU may limit performance to protect the engine. Faulty injectors can cause damage to the pistons and turbine over time.
If I just change one injector, is it okay?
It depends. Sometimes it is enough, but with high mileage it is advisable to test all and replace the weakest or out of spec ones.
Does cleaning injectors with additive really solve the problem?
If the injectors are only dirty or slightly clogged , yes. If there is an electrical fault or internal wear , no.
🧠 Conclusion
Engine light on and codes P022664, P02023A and P02033A on a Mercedes CLA diesel with high mileage are symptoms of problems with the injection system and the accelerator control. By acting specifically on:
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Cleaning contacts and wiring
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Electrical control of injectors
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Possible replacement of accelerator pedal
you can solve the problem effectively , avoiding unnecessary expenses and keeping the engine efficient.
