B132A : Air conditioning circuit low pressure safety fault

[BobcatJones]

Hey all,

I'm doing some fault clearing on my 508 and I can't seem to get rid of this one on the BSI.

----
B132A : Air conditioning circuit low pressure safety fault
Characterisation : Signal below the tolerance range
Status : Temporary
Location : local
Variables associated with the fault

----

Can anyone help with interpretation of this? Is this a low refrigerant fault?

[GiveMeABreak]

Yes, this fault means there is an A/C circuit low pressure safety fault, so it has declutched the compressor for safety reasons. The signal is below the tolerance range.

Whilst this is in effect the A/C will be cut off. Your suspect areas are going to be the Air conditioning pressure sensor or the electrical harness.

[BobcatJones]

Thanks Marc,

You are really my go to at the moment

Replacement of the pressure sensor would require breaking into the refrigerant circuit right?

[GiveMeABreak]

When the pressure of the air conditioning fluid is below 2.5 bar, the air conditioning compressor is cut off.
The air conditioning compressor is triggered again when the air conditioning fluid pressure increases to above 3 bar.

So it might be worth getting the system checked and get an A/C recharge first to see if there is a leak or it's low on refrigerant. It might just be that.

But in case you need to check the sensor, the pressostat is located here - I have marked it with a green arrow:

[frer8833]

I ran diagnostics with Ediag Kingbolen and it showed fault code for fan P0495 and P0494, both intermittent, fanspeed is not correct/no speed, wiring is shorted to earth, battery or open circuit. And B132A (intermittet), low ac circuit pressure.Yellow Service light is on with 3 beeps.

Does low ac circuit pressure mean low refrigerant? Can low refrigerant cause P0495 and P0494? What's the relationship? Can all these faults be caused by being hit by another object/car?

[GiveMeABreak]

Here are the fault code descriptors for you:

Of course, if there is a leak in the A/C circuit it will cause loss of gas / pressure. However if you look at fault P0495, you will see that one of the downgrade modes is disengagement of the A/C compressor whilst this fault is active.

It may well be that you have a fault in the fan / fan assembly.

Fault Code:	P0494
Description of Fault:	2 speed cooling fan: Incoherence between the reference value (low speed) and the status of the fan assembly. Incoherence between the reference value (low speed) and the status of the fan assembly (For 5 seconds).
Conditions for Fault to clear:	Activation of the cooling fans unit
Downgrade Modes whilst Fault is active:	-
Symptoms:	Engine overheating with illumination of the engine coolant temperature indicator light Absence of automatic stopping of the internal combustion engine (If the vehicle has the Stop and Start system)
Suspect Areas:	Fan assembly Fuse Electrical harnesses Connectors

Fault Code:	P0495
Description of Fault:	2 speed cooling fan: Incoherence between the reference value (high speed) and the status of the fan assembly. Incoherence between the reference value (high speed) and the status of the fan assembly (For 5 seconds).
Conditions for Fault to clear:	Activation of the cooling fans unit
Downgrade Modes whilst Fault is active:	Activation of the cooling fan at fast speed Request for immediate disengagement of the air conditioning compressor Switching of the turbocharging pressure regulation to controlled mode Switching to fuel "normal reduced flow" mode Deactivation of the request for regeneration of the particle filter from the diagnostic tool Switching on of the warning lamp and/or warning message: "SERVICE" warning lamp
Symptoms:	Engine overheating with illumination of the engine coolant temperature indicator light Absence of automatic stopping of the internal combustion engine (If the vehicle has the Stop and Start system)
Suspect Areas:	Fan assembly Fuse Electrical harnesses Connectors

[frer8833]

There is also a horn fault code B1156. It is described as short circuit in engine wiring house. Is it a coincidence or does it point to a common fault that both the horn fault and the cooling fan fault have short circuit in wiring harness? Does horn wiring and cooling fan wiring share same harness? Do you have electrical diagram or can you guess the cause and how to repair? Can 'Risk-of-dpf-clogging' or limp mode stress or heat up the cooling fan or electrical wirings to the point of failure?

[GiveMeABreak]

There are 2 parts of the code missing. There should be 2 more digits at the end, so could be any of these three:

Fault Code:	B1156 11
Description of Fault:	Horn fault: Short circuit to earth. Horn operated. Short-circuit to earth detected for 2 seconds.
Conditions for Fault to clear:	Absence of malfunctioning and activation of the control
Downgrade Modes whilst Fault is active:	Deactivation of the control of the output affected by the fault
Symptoms:	The horn cannot be activated
Suspect Areas:	Electrical harness Engine fusebox Horn

Fault Code:	B1156 12
Description of Fault:	Horn fault: Short circuit to positive. Horn not controlled. Short-circuit to positive detected for 2s.
Conditions for Fault to clear:	Absence of malfunctioning and activation of the control
Downgrade Modes whilst Fault is active:	-
Symptoms:	Unwanted activation (control not pressed) of the horn
Suspect Areas:	Electrical harness Engine fusebox

Fault Code:	B1156 13
Description of Fault:	Horn fault: Open circuit. Horn not controlled. Open circuit detected for 2 seconds.
Conditions for Fault to clear:	Absence of malfunctioning and activation of the control
Downgrade Modes whilst Fault is active:	-
Symptoms:	The horn cannot be activated
Suspect Areas:	Earth Engine fusebox Electrical harness Horn

[frer8833]

I looked through the grill and other openings but I can't see any horn. Do you have electric diagram for horn and cooling fan so I can trace the cables from fuse or relay box to them and test with multimeter where is the short or open circuit? Do you know where are the relays and fuses for horn and cooling fan?

[frer8833]

Here are the fault code descriptors for you:

Of course, if there is a leak in the A/C circuit it will cause loss of gas / pressure. However if you look at fault P0495, you will see that one of the downgrade modes is disengagement of the A/C compressor whilst this fault is active.

It may well be that you have a fault in the fan / fan assembly.

Fault Code:	P0495
Description of Fault:	2 speed cooling fan: Incoherence between the reference value (high speed) and the status of the fan assembly. Incoherence between the reference value (high speed) and the status of the fan assembly (For 5 seconds).
Conditions for Fault to clear:	Activation of the cooling fans unit
Downgrade Modes whilst Fault is active:	Activation of the cooling fan at fast speed Request for immediate disengagement of the air conditioning compressor Switching of the turbocharging pressure regulation to controlled mode Switching to fuel "normal reduced flow" mode Deactivation of the request for regeneration of the particle filter from the diagnostic tool Switching on of the warning lamp and/or warning message: "SERVICE" warning lamp
Symptoms:	Engine overheating with illumination of the engine coolant temperature indicator light Absence of automatic stopping of the internal combustion engine (If the vehicle has the Stop and Start system)
Suspect Areas:	Fan assembly Fuse Electrical harnesses Connectors

I have problem P0495 with Service warning lamp and which triggers a reduction in horsepower. Open circuit or shorted to ground circuit in the wiring harness. Radiator fan and resistor are replaced but fan is still not spinning. Is there a specific wiring diagram for radiator fan wiring in my car model's case? I read that it can be caused by also too high voltage to the fan. I haven't heard the fan work in many years except when returning from a 5 hour long ride, then it started spinning during 8 min and ECO (start/stop) light also came on, usually it just blinks. It does not spin even when cabin air circulation is set to highest speed and lowest temp and AC button is ON.

I have written more about the symptoms etc here viewtopic.php?p=804128#p804128

[GiveMeABreak]

You'll need to provide your VIN for me and I'll see if I have one. Please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff.

[frer8833]

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

[GiveMeABreak]

Here you are:

With the exception of the wiring codes, most of the component codes are indexed here:

PSA Electrical Diagrams - Wiring & Symbols Codes Index

General Cooling System


Detail Cooling System


Location

[ozvtr]

Ok now we can get somewhere.
It looks like the engine ECU monitors the fan power on pin4 of the 4 pin grey connector of the fan controller, 1522. So it seems that there is no fan power to the fan controller!?
First up check for +12V at pin 2 of the 2 pin grey connector on 1522 (the connector on the wiring loom side). There should be power there all the time. If you DO NOT have power, check fuse F5 in the engine bay auxiliary fuse box, 1032. Check for power on both sides of the fuse with the fuse in situ.

[frer8833]

Ok now we can get somewhere.
It looks like the engine ECU monitors the fan power on pin4 of the 4 pin grey connector of the fan controller, 1522. So it seems that there is no fan power to the fan controller!?
First up check for +12V at pin 2 of the 2 pin grey connector on 1522 (the connector on the wiring loom side). There should be power there all the time. If you DO NOT have power, check fuse F5 in the engine bay auxiliary fuse box, 1032. Check for power on both sides of the fuse with the fuse in situ.

Is the "auxiliary fuse box" the main fuse box furthest to the right in the picture?



Image depicts the fuse box in my car:


I look at the Type 1 fuse box diagram on this website https://fuseandrelay.com/citroen/c4.html and https://car-box.info/citroen/c4/b7-2011-2018.html, Idk if it shows box 1032. There it says "F5 Engine and air intake fan control module, Amp 15", is it the light blue one (F5) at the bottom of this picture. I looked at both blue fuses F5 and F11 and they look good, I also switched their positions, but it didn't solve the error. But it is also written there "F2 Two-speed cooling fan", it's maybe the radiator/cooling fan resistor's fuse? I checked it today but it didn't make a difference.

There are fuses on the battery too, "FL12 (60A) Cooling fan motor".

There are also Maxi fuses, "MF1 30 A / 50 A Engine cooling fun [fan]" but it is maybe for other car model.

This means the problem is in the wire between fuse box and radiator fan's power outlet socket?

I guess that either the wire gauge is too low to handle high speed fan voltage and amp (burned/melted, should've blown the fuse), wire mechanical damage or corrosion at the contact points (contact cleaner needed)?

Idk how to change wire or access easily the fan except removing the engine bay's underside protective cover but it is tight with space.