Technical Code P0645

[frankie70]

CODE P0645, Fiat Ducato 2.0JTD X244, Engine Light on with Code P0645 AC Relay , I HAVE NO AIR CON, Is the code a Generic Code. ? And where is the AC Relay. Have changed Fan relays Fuses ok Engine runs, starts ok, checked the connections from Under bonnet fuse box, Relay to ECU, Can clear the light but soon as start the engine its back on Any ideas would be very much appropriated, Thank You

 

[bugsymike]

CODE P0645, Fiat Ducato 2.0JTD X244, Engine Light on with Code P0645 AC Relay , Have changed Fan relays Fuses ok Engine runs, starts ok, checked the connections from Under bonnet fuse box, Relay to ECU, Can clear the light but soon as start the engine its back on Any ideas would be very much appropriated

I had similar problem on a Citroen and it was an air con gas leak so it wouldn't activate the magnetic switch on fan pulley via the relay.
Although in my case it didn't show an error code, but appeared to have an air con gas pressure reading.

 

[theoneandonly]

Starting with a zero it is a generic error from my database
Ducato P0645 AC Relay Command
Fiat 2 P0645 Command relay air conditioner

 

[frankie70]

Starting with a zero it is a generic error from my database
Ducato P0645 AC Relay Command
Fiat 2 P0645 Command relay air conditioner

Thatk you, How do i remove the code

 

[theoneandonly]

Are you using multiecuscan or a cheap generic reader (these may not be able to delete the codes.) a better scan tool may be required. The code related to AC when you havent got it is a tad confusing but cheap generic readers don't always get it right.

 

[frankie70]

Are you using multiecuscan or a cheap generic reader (these may not be able to delete the codes.) a better scan tool may be required. The code related to AC when you havent got it is a tad confusing but cheap generic readers don't always get it right.

Hiya am using a THINKDIAG MINI bluetooth, device have tried my sons expensive scanner and it comes up with the same Code P0645 A.C.Relay

 

[the green vanper]

Is your son's expensive scanner a FIAT dedicated one?

Use MultiEcuScan or AlfaOBD. And the appropriate interface.

 

[bugsymike]

Is your son's expensive scanner a FIAT dedicated one?

Use MultiEcuScan or AlfaOBD. And the appropriate interface.

I see OPs Ducato is a 2.0JTD , I had a 2.0 litre in a 2010 Scudo which as they use the Peugeot RHR engine in that model MES would not recognise it but Gendan were able to recommend MaxiEcu scan tool which was able to cover that as well as rest of Fiat range, so may be worth asking before purchase.

 

[the green vanper]

Searching with Peugeot+P0645 I've found a thread describing a problem with the A/C and the same error on a Peugeot Boxer. Photos in the thread show a typical FIAT fusebox though.

The problem in the thread was caused by bad fan cables going to the fusebox. But the OP says in the first post he checked the cables.

In the other thread the problem was more complicated, as the van had no A/C ex-factory, which was added afterwards. He needed to replace the fusebox with one from a van with A/C and add the A/C in the ECU (I assume it was not in the ECU itself, but the whole system). There was no mention which program they used to do it, only a question if it could be done with Lexia and a confirmation 3 days later of a successful resolution of the problem.

 

[frankie70]

Is your son's expensive scanner a FIAT dedicated one?

Use MultiEcuScan or AlfaOBD. And the appropriate interface.

Have no idea what the make is, he uses it in his work

 

[frankie70]

Have no idea what the make is, he uses it in his work

Banging my head on a brick wall . Have just tried another scanner and the same code come up ?? have had all the wiring out from the Under bonnet fuse box to the ECU and cannot trace any faults The "Engine Light" came on when in Cornwall, Done 1000 mile with it on , So i thought id have a look,

 

[the green vanper]

Just an idea: how those universal code reader work? Do you have to choose the model of the vehicle? If so, according to what @bugsymike wrote, perhaps instead of choosing x244 Ducato the corresponding Peugeot model should be chosen to have the correct readings?

 

[Zardo]

0	COMPONENT CONCERNED	PRELIMINARY CHECK	OK (NO FAULTS DETECTED)	FAULT DETECTED	OPERATION
	Engine management control unit	Check if "Overtemperature" is shown in the error details	Go to Step 1	The error detail is "Overtemperature"	Go to Step 5

Steps 1 to 4 are about the Air conditioning relay wiring and the air conditioning relay (checking for short circuits to Earth, battery or open circuits or the relay)

Step 5 is checking if the EMCU is working correctly and if not, replace the EMCU

This fault number concerns the error codes of the 937 BOSCH DIESEL INJECTION EDC17C49 CF5/EOBD CAN (EP 2.0 ENG.) of the 250 Ducato 2.0 JTD/Euro5 with 115 HP (the CAN node which claims to have detected a fault pointing to the conditioner relay control).

Is that your model?

 

[the green vanper]

the 250 Ducato 2.0 JTD/Euro5 with 115 HP (the CAN node which claims to have detected a fault pointing to the conditioner relay control).

Is that your model?

No, the OP has the x244 with the apparently Peugeot's 2.0 diesel.

 

[Zardo]

Looks like I can't get codes for the 244. However, if the same Bosch Can EMCU node is used, this error should point to the same stuff, as it is the case for some other Fiat diesel cars: likely a wiring issue or the module itself is faulty, or maybe dirt in the connector?

 

[the green vanper]

The ECU is probably different.

The 2.0 115 HP euro5 engine is a FIAT engine with 1956 ccm, DOHC 16 v.

The OP's engine is a 2.0 84 HP DW10UTD PSA engine with 1997 ccm, OHC 8 v. From what I've found over the internet, it was euro3/4. It used a Common Rail Bosch CP1 or Siemens SDI 801.

 

[Zardo]

Yes but I found a description for the 244 2.0 JTD Ducato, so the EMCU has this ability, but if there is no compresser present, the error only makes sense if the EMCU is either faulty or it "sees" something present. A problem with the wiring or the connector might trigger a bizarre fault.

Control of air conditioning system activation
The injection control unit manages the air conditioner system compressor electromagnetic coupling in accordance with a strategy designed to avoid operating conditions that would impair engine performance.

When the compressor is activated, the engine control unit increases the amount of fuel at idle speed to adjust the engine to the higher power requirement and cut off power supply to the compressor under conditions of:

high power demand from the engine (fast acceleration);

engine coolant overheating.

 

[the green vanper]

We've suggested the wiring problem, but the OP confirmed it was checked. Personally I'd also stick to that cause.

 

[bugsymike]

Just an idea: how those universal code reader work? Do you have to choose the model of the vehicle? If so, according to what @bugsymike wrote, perhaps instead of choosing x244 Ducato the corresponding Peugeot model should be chosen to have the correct readings?

If it reads the Vin. Number, it may still have issues, as I found trying to read a Vauxhall Combo 1.3 which is badge engineered Doblo 1.3 using my MaxiEcu Scan tool it wouldn't recognise it.
Although I could still do basic OBD on the Vauxhall using the MaxiEcu tool and I believe I can pay a fee to upgrade to include Vauxhall range and other makes extra per make.
The 2010 Fiat Scudo I had was the 16 valve 120Hp version the Peugeot RHR engine, so maybe OPs vehicle is slightly earlier if 8 valve Peugeot.
I haven't worked on the 2.0 litre 16 valve Fiat engine, at present I have two 1.6 Doblo MJs and a 1.3 MJ in the Vauxhall Combo.

 

[frankie70]

Just an idea: how those universal code reader work? Do you have to choose the model of the vehicle? If so, according to what @bugsymike wrote, perhaps instead of choosing x244 Ducato the corresponding Peugeot model should be chosen to have the correct readings?

Will have try with that ,, Thanks