Citroen C3 & C2 water damaged ECU

C2/C3 water damaged ECU

A common complaint for the Citroen C3 & C2 vehicles is water damage to the engine ECU, this results in the engine cutting out, refusing to rev, misfiring or the not starting.


Often there will be fault codes stored in the engine system that are blaming the throttle position, engine misfire or coolant temperature/O2 sensors. Despite these fault codes it is usually the engine ECU that has failed due to water contamination into the ECU multi-plug causing one or more of the terminals inside the ECU plug to corrode (if you disconnect the ECU plug then you will see the corrosion to the terminals), this is caused by water from the coolant system getting into the main engine wiring harness that travels along and into the ECU. Once the water has made its way to the ECU it then causes the corrosion to the pins which then causes a high resistance or open circuit for various engine sensor/actuator circuits resulting in the running symptoms described before.


If your ECU has been water damaged in this way, then we can fully test and rebuild your own unit with an unlimited mileage lifetime warranty*.


Common Failure symptoms:

  • Cutting out
  • Poor rev range
  • Misfire


Common fault codes:

  • P0121 - Throttle Signals 1 And 2 Incoherence
  • P1161 – Throttle Position Implausible Signal
  • P0123 – Throttle Position Sensor
  • P2176 – Motorised Throttle Programming
  • P1340 – Multiple Misfire Detected
  • P0135 – O2 Heater Circuit
  • P0115 – Coolant Temp Sensor Fault
  • P1631 – ECU Internal Malfunction


Affected Vehicles:


Common failing part numbers:

  • SW9664127180
  • SW9663717680
  • SW9661960880
  • 9664127180
  • 7052754374
  • 7144824009
  • 21586048-9A
  • 215860489A


Test and rebuild:

When we rebuild your own unit, it is fully tested in advance to ensure it is faulty before going ahead with the rebuild, all rebuilds come with an unlimited mileage lifetime warranty*. These ECU’s are programmed to the VIN (Vehicle Identification Number) and the coded key system so it is impossible to fit a second-hand unit from another vehicle as it would not run on your vehicle. When we rebuild your own ECU, we retain all of the original programming including the VIN and key code, so there is no need for any expensive recoding procedures when you receive it back, simple plug and play.



Your ECU will not require any programming once you receive it back after the rebuild, just plug it in and drive away.



We rebuild thousands of ECU’s for main dealers and specialist workshops all over the world so you be sure that once rebuilt, your ECU will not fail again.



Lifetime unlimited mileage*


How do I get my unit rebuilt?

To pay for the rebuild select your vehicle above and then click: Get yours rebuilt

Print the payment/booking confirmation email.

Package the Citroen C2/C3 engine management ECU inside a sturdy box with plenty of packaging material (make sure you include your confirmation email in the box).

Send us your package by tracked courier (the shipping instructions are on the confirmation email).

Once received we will test, rebuild and return your engine ECU with an unlimited mileage lifetime warranty. (if your unit turns out not to be faulty then we will refund your payment less a small testing fee and return shipping)


What if I don’t want to pay up front?

This is not a problem, if you prefer this option then follow the following steps:

Fill in and submit this test form.

Print the booking confirmation email.

Package the Citroen ECU inside a sturdy box with plenty of packaging material (make sure you include your confirmation email in the box).

Send us your package by tracked courier (the shipping instructions are on the confirmation email).

Once received, we will test your C2/C3 engine management ECU and call you to advise on the outcome of testing, if your unit is faulty and you choose to go ahead with the rebuild then we will take payment over the phone using a debit/credit card.

We will then rebuild your C2/C3 engine ECU and return it to you with an unlimited mileage warranty.

If you require further information regarding this Citroen C2/C3 engine ECU then please contact us.

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Comments on "Citroen C3 & C2 water damaged ECU"
Terence callaghan says: 4/11/2019 7:21:00 PM
What is the estimate for rebuilding an ecu for a 2004 Citroen c3...and if it,s too faulty ,,what would be cost of replacement,,,thank you
ECU Admin says: 6/11/2019 2:18:02 PM
Hi Terence, for rebuild and replacement prices and shipping information please select your engine ECU part number from the following list:
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