Berlingo Airco problem C72A- B -D -E

Post your Cit/Peu/Ren air conditioning queries or advice.

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blownelco
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Berlingo Airco problem C72A- B -D -E

Post by blownelco »

Hello,

Need help on fixing my airco on Citröen Berlingo B9 model.
Last summer the airco failed to work, instead of getting cool air it was blowing very hot air into the car.

The hot air blowing stopped by itself.

I checked the compressor clutch and it wasn't working anymore, the coil was burned through.
I relaced the coil, refilled the gas. It worked for about 4 weeks.

Now the compressor doesn't work anymore ( not engaged ).

I bought a diagbox device and checked the car.
The compressor works when testing the coil.

I have following errors in the clima unit:

C72A Recirculation motor fault : Open circuit
C72B Distribution motor fault : Open circuit
C72D Driver's mixing motor fault : Open circuit
C72E Passenger mixing motor fault : Open circuit

CLIMA_REGULEE - DENSO

Anyone a clue what is broken now?


thanks

thanks in advance

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GiveMeABreak
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Re: Berlingo Airco problem C72A- B -D -E

Post by GiveMeABreak »

Pop your VIN up please so I can see the system you have and to check those errors against the specific system.

It's highly unlikely that all mixing and distribution motors have failed at the same time, so that leaves the A/C climate control ECU or a wiring fault somewhere - anyway I'll have a better idea when I know what you have.

blownelco
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Re: Berlingo Airco problem C72A- B -D -E

Post by blownelco »

How can i send my VIN ?

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Re: Berlingo Airco problem C72A- B -D -E

Post by Hell Razor5543 »

You can post the VIN in this thread. It will automatically be obscured (for security reasons) so that only Forum staff can read it.

blownelco
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Re: Berlingo Airco problem C72A- B -D -E

Post by blownelco »

VIN: VF7**************[VIN obfuscated, can be read by forum staff]

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GiveMeABreak
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Re: Berlingo Airco problem C72A- B -D -E

Post by GiveMeABreak »

Ok, so looking at all these fault codes, they all refer to similar conditions - loss of power / communication. So the first thing I suggest you do is re-trace your steps when you did the last replacement / repair work and double check all the wiring connections and plugs to the A/C compressor and in that area generally. I suspect that it is a wiring fault were there is loss of signal - so check the connectors under the compressor - clean them up and make sure there are not cuts in the wiring for a short / open circuit. Trace the wire back and make sure there is no damage and re-check anything else you did at the time in any other area.
Fault Code: C72A

Description of Fault:Air recirculation motor fault: Short circuit to earth; Short circuit to positive; Open circuit; Reduction motor jammed; Loss of communication. Reduction motor overheating (Locked); Short circuit; Open circuit on the coil, or reduction motor supply voltage lower than 3.5V, or loss of LIN communication for 2.6s, or undervoltage lower than 7.5V, or overvoltage higher than 17.5V.

Downgrade Modes whilst Fault is active: Fixed Position

Symptoms: Malfunction: Recycling of air; Malfunction: Demisting-defrosting

Suspect Areas: Supply harness: Recirculation motor; Air conditioning ECU; Recirculation motor; Air conditioning uni
Fault Code: C72B

Description of Fault: Distribution motor fault: Short circuit to earth; Short circuit to positive; Open circuit; Reduction motor jammed; Loss of communication. Reduction motor overheating (Locked); Short circuit; Open circuit on the coil, or reduction motor supply voltage lower than 3.5 V, or loss of LIN communication for 2.6s, or undervoltage lower than 7.5V, or overvoltage higher than 17.5V.

Downgrade Modes whilst Fault is active: Fixed Position

Symptoms: Malfunction: Air distribution; Malfunction: Demisting-defrosting; Malfunctioning of the production of warm air; Malfunctioning of the production of cold air; Malfunctioning of regulation of the temperature requested.

Suspect Areas: Supply harness: Distribution motor; Air conditioning ECU; Distribution motor; Air conditioning unit
Fault Code: C72D

Description of Fault: Fault in the front LH mixer motor: Short circuit to earth; Short circuit to positive; Open circuit; Reduction motor jammed; Loss of communication. Reduction motor overheating (Locked); Short circuit; Open circuit on the coil, or reduction motor supply voltage lower than 3.5V, or loss of LIN communication for 2.6s, or undervoltage lower than 7.5V, or overvoltage higher than 17.5V.

Downgrade Modes whilst Fault is active: Fixed Position

Symptoms: Malfunctioning of the production of cold air; Malfunctioning of the production of warm air; Malfunctioning of regulation of the temperature requested.

Suspect Areas: Supply harness: Front LH mixer motor; Air conditioning ECU; Front LH mixer motor; Air conditioning unit
Fault Code: C72E

Description of Fault: Fault in the front RH mixer motor: Short circuit to earth; Short circuit to positive; Open circuit; Reduction motor jammed; Loss of communication. Reduction motor overheating (Locked); Short circuit; Open circuit on the coil, or reduction motor supply voltage lower than 3.5V, or loss of LIN communication for 2.6s, or undervoltage lower than 7.5V, or overvoltage higher than 17.5V.

Downgrade Modes whilst Fault is active: Fixed Position

Symptoms: Malfunctioning of the production of cold air; Malfunctioning of the production of warm air; Malfunctioning of regulation of the temperature requested.

Suspect Areas: Supply voltage of the front RH mixer motor; Air conditioning ECU; Front RH mixer motor; Air conditioning unit

blownelco
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Re: Berlingo Airco problem C72A- B -D -E

Post by blownelco »

Hello,

I have checked the connections but didn't find anything.
While testing i have noticed that the front RH mixer motor didn't run while changing the right side.
After restarting it worked again. I also could clear the errors. But still the airco pump is not working.

When testing the clutch it gets encaged, so no problem here.

Does anyone know where the airco ECU is located in this car? I removed the panel ( electronic control) but it's not behind it.

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Re: Berlingo Airco problem C72A- B -D -E

Post by GiveMeABreak »

The Climate control ECU is inside the control panel.

Look at the fault code sections above where is says 'Downgrade Modes' - when you have any one of the faults active, then the distribution or mixer motors will NOT change position (Fixed Position) until the fault clears. So don't think it is necessarily the right hand mixer motor at fault if you have the C72E fault active.

blownelco
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Re: Berlingo Airco problem C72A- B -D -E

Post by blownelco »

I have bought a new motor to replace the front RH mixer motor.

Can i just replace the motor, or does it need programming? Diagbox?

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Re: Berlingo Airco problem C72A- B -D -E

Post by GiveMeABreak »

The stepper motors don't need coding

blownelco
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Re: Berlingo Airco problem C72A- B -D -E

Post by blownelco »

How do you explain that?

All 4 motors are the same, connected in series ( date in -> first motor data out - > secondmotor...)

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Re: Berlingo Airco problem C72A- B -D -E

Post by GiveMeABreak »

The motors are simple stepper motors and these (depending on type of climate control or A/C fitted) will control the Air Distribution and Air Mixing functions. They do not have individual ECU in them, so need no coding to the vehicle.

When you say the "airco pump" in your post above, are talking about the A/C compressor? Of the clutch is engaging and disengaging when you switch the A/C on and off, then if there is no cold air in the cabin, you may be low on Gas and needing a top up.

I would rule out all the common / obvious things first before replacing motors.