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Citroen C3 II error P0493 - Car enters emergency mode 30km / h

Posw580 36213 18
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Why does the radiator fan on a 2014 Citroën C3 1.4 HDi not start in diagnostic mode even though the relay clicks, the fan works on direct 12 V, and fault P0493 is stored?

Check whether the fan is actually getting both supply and ground at the controller/fan connector when Lexia commands it on, because a clicking relay means the control side is working but the motor may still be missing plus or minus [#16909310][#16910145] Inspect the fan controller/module and its wiring/connectors, since P0493 can be caused by a faulty fan motor, relay, wiring/connector problem, or a fan control module fault [#16909947][#16909357] Also verify the large engine-compartment fuse, including the 70 A fuse under the fuse box, even if the smaller fuses are OK [#16910372] In this model, the diagnostic fan test should still run the fan; if it does not, the fault is in the fan power path or controller rather than the temperature sensor alone [#16910145][#16909651]
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  • #1 16909055
    Posw580
    Level 12  
    Posts: 224
    Rate: 60
    Hello, I bought a broken c3 from 2014. with 1.4 HDI engine
    Car done, I have a problem because the car after entering the emergency mode.
    Lexia has shown an error P0493 - inconsistency between the setpoint (no control) and the state of the radiator fan group
    Fuses checked, Radiator fan relay replaced by a colleague and the same.
    The fan connected directly to 12V works.

    What to check.
    In Lexi, when he is asked to turn on the fans, you hear the sound of the relay but the fan does not start ??

    PLEASE HELP.
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  • #2 16909310
    Megawe
    Level 34  
    Posts: 2657
    Help: 246
    Rate: 1423
    If the relay sounds, you need to check if the fan is missing a plus or a minus.
  • #3 16909357
    wqq
    Level 22  
    Posts: 395
    Help: 48
    Rate: 172
    In c3 you have probably 3 types of fans ...
    If you have an electronic module then look for the reason there ...
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  • #4 16909651
    Anonymous
    Anonymous  
  • #5 16909679
    Posw580
    Level 12  
    Posts: 224
    Rate: 60
    No fan from the beginning does not work. Connected briefly to the battery, it works, so the fan fault disappears.
    In Lexi, when it calls the program to check the fan assembly, is the cycle relay and the fan silent ??

    Where is this temperature sensor to check ??
  • #6 16909766
    lemmak
    Level 21  
    Posts: 296
    Help: 40
    Rate: 97
    The right side of the engine (standing in front of it) at the height of the head. Most likely green, 2 pin, near the plastic thermostat housing (I write from memory - I'm wrong - please correct it).
    As your colleague wqq rightly pointed out, there are different types of fans - you need to track down the fan module - it's likely the culprit of your troubles.
  • #7 16909913
    Posw580
    Level 12  
    Posts: 224
    Rate: 60
    Gentlemen, what module are we talking about?
    my C3 only has electronics with a resistor (it was also replaced), the fan does not work. And the second thing is the driver with the relay (photo attached) also replaced and nothing.
    Attachments:
    • Citroen C3 II error P0493 - Car enters emergency mode 30km / h 447d5dd57a24f0070d9cd56a801ad3bc.jpg (22.79 KB) You must be logged in to download this attachment.
  • #8 16909947
    lemmak
    Level 21  
    Posts: 296
    Help: 40
    Rate: 97
    It is about this module - the controller, "call it, call it" - you have changed it, I hope it works - it falls off.
    Let me quote the advice (translation from the translator):

    P0493 is a generic OBD-II code for a voltage problem with the electric fan control system because the signal sent to the engine computer is incorrect. That is, there is a bad "soil?" or the fan does not work.
    P0493 can be caused by many reasons, but the most common causes are:

    Electric fan motor defective
    Faulty electric fan relay
    Faulty wiring and fan electrical connectors
    Defective engine coolant temperature sensor
    Blower electric fuse blown
  • #9 16910038
    Posw580
    Level 12  
    Posts: 224
    Rate: 60
    That's how I changed from another car that worked in it. So ..... as I wrote earlier.
    When the fan is activated from the program, the relay ticks in this module but the fan does not start.
    I still have the error of some evaporator sensor (but I do not know where it is and what sensor it is) maybe he is the culprit.
  • #10 16910145
    lemmak
    Level 21  
    Posts: 296
    Help: 40
    Rate: 97
    Look for it in the air conditioning system. The activation from the program should turn on the fan despite the incorrect signal from this sensor. Check if the controller is "-" and "+". And what comes to the fan during testing.
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  • #11 16910264
    Posw580
    Level 12  
    Posts: 224
    Rate: 60
    can you specify where to check the voltage at this sensor is it coming ??
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  • #12 16910372
    Anonymous
    Anonymous  
  • #13 16910387
    Posw580
    Level 12  
    Posts: 224
    Rate: 60
    Fuses checked all and large and small
  • #14 16911280
    Anonymous
    Anonymous  
  • #15 16912496
    Posw580
    Level 12  
    Posts: 224
    Rate: 60
    Since the evaporation sensor error has no effect, I don't know what could be. why the fans are not working.
    how to check if there is a 12V to the controller ??
  • #16 16912971
    wqq
    Level 22  
    Posts: 395
    Help: 48
    Rate: 172
    Posw580 wrote:
    Hello, I bought a broken c3 from 2014. with 1.4 HDI engine


    I hope your cables are tidied up ...
  • #17 16913690
    Posw580
    Level 12  
    Posts: 224
    Rate: 60
    So the installation was not touched.
  • #18 16916060
    Anonymous
    Anonymous  
  • #19 20807691
    śmiały mały
    Level 1  
    Posts: 1
    Hello,and what problem solved?
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Topic summary

✨ The discussion revolves around a 2014 Citroen C3 II with a 1.4 HDI engine experiencing an emergency mode activation due to error code P0493, indicating an inconsistency in the radiator fan control system. The user has checked fuses and replaced the radiator fan relay, but the fan does not operate despite functioning when directly connected to 12V. Responses suggest checking the fan's power connections, the engine coolant temperature sensor, and the fan control module. The importance of verifying the air conditioning system's functionality is also highlighted, as it may affect fan operation. The user is advised to check for voltage at the temperature sensor and ensure all wiring is intact.
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FAQ

TL;DR: Citroën C3 II P0493 usually traces to fan control power/ground or the fan module; the coolant sensor is a 2‑pin unit. “Track down the fan module.” [Elektroda, lemmak, post #16909766] Why it matters: P0493 can trigger limp mode and poor cooling, so quick electrical checks restore drivability.

Quick Facts

This FAQ is for C3 II owners and techs diagnosing P0493, no‑start fans, and limp‑mode behavior after repairs or AC faults.

What does P0493 mean on a Citroën C3 II?

P0493 indicates the ECU’s commanded fan state doesn’t match actual fan feedback. Lexia/Diagbox labels it an inconsistency within the radiator fan group. This points to control power/ground, the relay/module, wiring, or a blocked strategy. Confirm the fan spins with a direct 12 V feed to isolate the motor from controls. [Elektroda, Posw580, post #16909055]

Where is the coolant temperature sensor and how many pins does it have?

Stand in front of the car. Look on the right side of the engine, near the plastic thermostat housing at head height. The sensor is typically green and uses a 2‑pin connector. Inspect for corrosion, broken tabs, or pulled wires. Poor readings or open circuits can confuse fan logic and log P0493. “Track down the fan module.” [Elektroda, lemmak, post #16909766]

Relay clicks but the fan won’t spin—what should I check first?

If the relay audibly clicks, verify whether the fan is missing its positive or negative feed at the motor. Use a test light while commanding the fan in Lexia. A click without voltage at the motor points to wiring, module, or fuse path rather than the relay coil itself. “Check if the fan is missing a plus or a minus.” [Elektroda, Megawe, post #16909310]

How do I verify 12 V and ground at the fan controller?

Command the fan with Lexia. Back‑probe the controller’s power and ground pins using a load‑type test light. The fan should run from tester command even with some AC sensor faults. If power and ground are present yet the fan is still off, suspect the controller or downstream wiring to the motor. [Elektroda, lemmak, post #16910145]

Which fuse feeds the radiator fan circuit on the C3 II?

Check the large fuses under the engine‑bay fuse box. A 70 A fuse on the left side was noted for the fan feed. Remove the box to inspect and voltage‑drop test the high‑current link. Replace any heat‑stressed or cracked fuse and clean terminals before refitting. [Elektroda, 2872687, post #16910372]

My fan runs on direct 12 V. What does that prove?

A direct 12 V jump shows the fan motor is healthy. The fault then lies upstream: supply fuse, relay/module, wiring, ECU command, or strategy inhibition. Continue by verifying controller power, ground, and command while using Lexia’s actuator test. [Elektroda, Posw580, post #16909055]

Can an air‑conditioning fault block the radiator fan from starting?

Yes. On this model the fan also serves the AC condenser. A non‑working AC system can inhibit fan operation, affecting cooling strategy. Restore refrigerant/pressure sensor function or use Lexia’s test to confirm the electrical path regardless of AC inputs. [Elektroda, 2872687, post #16916060]

What is the evaporator/pressure sensor and should I bridge it?

It’s part of the AC system’s pressure monitoring that informs fan/condenser control. Low refrigerant or sensor faults can log errors and influence fan logic. Bridging pins without a wiring diagram risks damage. If needed, identify the exact pins from a schematic before any jumper test. [Elektroda, 2872687, post #16911280]

How many radiator fan types were used on C3 platforms?

Three fan designs appear across C3 variants: simple resistor‑based two‑speed, electronic module‑controlled, and other sub‑variants. Identify your assembly before testing, as diagnostics and expected voltages differ. Module‑based units often fail at the controller, not the motor. [Elektroda, wqq, post #16909357]

What’s a fast 3‑step way to diagnose P0493 on a C3 II?

  1. Use Lexia to command fan operation; note if the fan starts.
  2. Back‑probe the controller for 12 V and ground during the test.
  3. If power/ground are present yet no spin, replace or repair the controller or wiring to the motor. [Elektroda, lemmak, post #16910145]

Does the tester command bypass a bad temperature or AC sensor?

The tester’s actuator test should start the fan even if an AC sensor reports a fault. If it doesn’t, focus on power/ground at the controller and the motor path. Sensor diagnosis can follow once electrical integrity is confirmed. [Elektroda, lemmak, post #16910145]

Edge case: Fuses look fine but the fan still won’t run—what then?

Large fuses can hairline‑crack or overheat under the engine‑bay box. Remove and load‑test the 70 A link, then inspect the underside terminals for heat damage. Replace suspect links and clean/retension spades to restore full current capacity. [Elektroda, 2872687, post #16910372]

Will fixing the AC restore normal cooling fan behavior?

Restoring refrigerant charge or resolving AC pressure sensing can re‑enable proper shared fan logic. After repairs, rerun Lexia actuator tests and monitor fan cut‑in during warm‑up. This confirms both ECUs agree on command and feedback, clearing P0493. [Elektroda, 2872687, post #16916060]

What module did other users replace when chasing P0493?

Users referenced the radiator fan controller/resistor pack near the shroud. Swapping in a known‑good unit restored operation in donor cars, but wiring and supply must still be verified in the target vehicle. The relay can click without delivering motor voltage. [Elektroda, Posw580, post #16910038]

What did the original poster already try?

They replaced the radiator fan relay and resistor/module, checked fuses, and confirmed the fan motor spins on direct 12 V. The relay audibly clicked in test mode, yet the fan stayed off. That focuses diagnosis on supply, ground, or control wiring. [Elektroda, Posw580, post #16909055]
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