Parking heater magnetic pump failure?

[siapelan]

I have (what I think is) an Ardic parking heater in my 2010 XC90. When I try to start it, it seems to start as normal, I can hear the 'fan' like sound in the front left part of the car, but then it stops after about a minute. No diesel of exhaust smell from the outlet of the diesel heater.

Normally, I would expect a kind of 'clicking' sound from the magnetic pump located under the car (approximately under the right rear seat), but there is no sound from that pump, so I think it is not working as it is supposed to.

On this, I have some questions - if you know about this system, i would be extremely happy if you are able to address all of them

1. I know there is a way to 'reset' the whole parking heater system, but since it seems to be starting (without getting diesel), it appears to me that there is no need to reset the system?
2. If I should reset the system, how do i do it (I know it has something to do with the fuse, but not sure how to do it)
3. What kind of electrical power is 'input' to the magnetic pump. My multimeter shows 0V both for AC and DC - is it some kind of pulsing power that cannot be metered with a normal multimeter?
4. If I am not able to meter any power with my multimeter, does this mean it is the power source that is faulty? The cable goes to a cable connector bridge under the rear right seat (inside the car), and then further into a large bundle of cables.
5. If it is a power failure, what can it be? Could it be that there are other fuses that the 'main' fuse (no 4)? Any other failure source?
6. Is there some way to test the magnetic pump using direct power to it? My understanding is that connecting direct 12V to does not help, since it is a magnetic pump?

Any other helpful comments are also appreciated

[SwissXC90]

I also have the fuel burning parking heater in my MY2009 XC90

The best thing to do is use VIDA (the Volvo diagnostic software)
VIDA will tell you what failure mode the heater is currently in

It will tell you why it failled to start

And you can test the individual components, like the combustion fan and the fuel pump

So if you don't have VIDA, find someone who does!

[siapelan]

Originally Posted by SwissXC90

The best thing to do is use VIDA (the Volvo diagnostic software)
VIDA will tell you what failure mode the heater is currently in

It will tell you why it failled to start

Thanks - I'll contact someone with the tool.

One question; the heater actually seems to start, but then stop again after not receiving diesel. If there is a failure code/mode, would the heater start at all?

[siapelan]

Originally Posted by siapelan

Thanks - I'll contact someone with the tool.

So; strange thing; a friend of mine had the diagnostic tool for Volvo, and there are no failure codes related to the Auxiliary/Parking heater system. I also tested the "DTCS IN VEHICLE" in the car, and no failure codes related to the heater system there as well.

---- >>>> One thing that can help me: What kind of power should go into the magnetic pump? I seem to remember that it should be some kind of pulsating power (and not 'regular' DC); how is it and how can it be measured e.g. with a voltmeter?

[SwissXC90]

Are you SURE you have a fault?

The parking heater is delivered in 3 variants:

Engine preheater: switches on automatically when the ambient temperature AND the coolant temperature are cold enough. Pretty much standard fitment on all Euro D5 diesels. Won't run if ambient / engine are warm. Basically it never fires up in Summer.

Programmable parking heater: Requires Engine preheater. A pure software add-on to the fuel-burning preheater. Alows you to manually turn the preheater on, and program it to preheat the engine. BUT if setting via program, will again only run if the engine coolant temp and ambient temp are cold enough. But you CAN run it in Summer.

Programmable parking heater with Remote Control: Requires Engine Preheater and Programmable Parking Heater. A physical remote control receiver addon to the AEM, to allow remote start of the parking heater via a keyring dongle.


With around 15°C ambient temp this morning, I fired up my diesel fuel-burning heater this morning to assist the D5 diesel to get up to normal temperature quickly, and it ran fine.

If you want, I can connect VIDA to it tomorrow and take some reading / screen shots of fuel pump performance.

I do hear the fuel pump ticking around 2x a second as it is maintaining fuel pressure for the pump.

The sequence is, from memory:
1. Combustion fan starts
2. Fuel pump starts
3. Ignitor starts
The heater fires up around 5 seconds after sequence start.

A common fault is the primitive flame sensor being covered in soot - thus the flame sensor thinks no flame, and cuts of the fuel delivery.
The flame sensor is in prinicple a light sensor, looking for light from the flame.
If covered in soot, it thinks no light thus no flame.
Solution. Dismantle, clean, reassemble.

Let me know if you want some VIDA readings...

[SwissXC90]

I've just checked the wiring diagram

The fuel pump motor is controlled by the CPM, via a an overheat thermal cutout on the heater itself.

[siapelan]

Originally Posted by SwissXC90

Are you SURE you have a fault?

Yes, i have the Programmable parking heater, which can be started manually, or set by timer (two alternative time settings). The heater looks very much like this one:

http://ftp.clubvolvo.ru/CARS%20DOCS%...0660852_en.pdf

The fuel pump for the parking heater is located under the car, approximately under the right rear seat. I do not hear any sound from the pump whatsoever when the heater starts, so either it is not getting electrical power, or it does not work.

---- >>>> My challenge is that I want to find out which it is (faulty pump or no power), and to be able to settle this I would like to know which power goes into the magnetic pump - is it a power that can be measured with a multimeter? It is not supposed to be stable 12V DC, but anyone knowing what it is?

Originally Posted by SwissXC90

The fuel pump motor is controlled by the CPM, via a an overheat thermal cutout on the heater itself.

Yes, the power is via a yellow cable from the CPM directly to the fuel pump. Then the other connection from the fuel pump is to negative ground.

I have always tried to start the pump when the engine is cold. Ambient temperature has been 10-15 degC, but I have put a bag of ice around the right mirror (the temperature sensor on these cars are located in the mirror casing), tricking the car to think it is about 7-8 degC. Thus, if the thermal cutoff works, it should send power to the fuel pump.

---- >>>> Do you know if the heater itself (the fan etc) would start if the overheat cutoff had been enabled? My heater starts 'as normal', but then cuts of after about 1 minute when it realise it is not getting diesel.

[siapelan]

Originally Posted by SwissXC90

The fuel pump motor is controlled by the CPM, via a an overheat thermal cutout on the heater itself.

Reading your post one more time; is there a reset button for this overheat function? I seem to remember that a similar system on a boat had such a reset button ... maybe that can be the problem?

[SwissXC90]

Originally Posted by siapelan

Yes, the power is via a yellow cable from the CPM directly to the fuel pump. Then the other connection from the fuel pump is to negative ground.

Not quite. "Directly" for me means no connectors or other devices in the path. The path is actually as follows:

The yellow wire exits the Combustion Preheater Module (CPM) (device 4/7) on pin 13.
It goes to the auxiliary heater module (device 9/30), where it goes through the thermal overtemp cutout switch - likely to be a simple bimetal switch contact.

It then exits the auxiliary heater module, still a yellow wire, and goes to pin 2 on heater harness connector 54/9 (6-pin gray, Engine compartment harness to heater harness).

Still a yellow wire, it then goes along the engine compartment harness to pin 13 on connector 54/3.1 (36-pin gray, Passenger compartment harness to engine compartment harness, located in passenger footwell, the largest connector in the entire vehicle)

Still a yellow wire, it then goes through the vehicle interior to pin 1 on motor 6/35 (Fuel pump, auxiliary heater, located on fuel tank)

I would, if I were you, check continuity of the following:

Fuel pump motor pin 1 to heater harness pin 2. Must be 0 ohms or close to it. If you have a poor connection, suspect first the heater harness connector (more exposed to the environment) and then the passenger compartment connector (unlikely).

Fuel pump motor pin 2 to ground. Pin 2 goes to junction 53/501 as a black wire, then to ground 31/67, still as a black wire.
Branching point 53/501 is located on the left hand side, front passenger compartment, inside the wiring loom, highly unlikely to be damaged.
Ground 31/67 is located at the Front seat riser, right-hand side (base of A-pillar). Possibly rusty if you have had any moisture ingress, otherwise unlikely to be damaged.

Check then presense of signal on pin 13 on connector 54/3.1. Disconnect battery then disconnect connector 54/3.1. Measure, using an ohmmeter, pin 13 to ground on the passenger compartment connector, ie: the wires going to the motor. You should be able to measure the motor impedance as 'something' - ie: not open circuit.

Then check integrity of heater harness connector 54/9. Check clean and dry and no dirt or moisture ingress. Clean the connector as required. Inspect for corrosion of pins, especially pin 2 (yellow wire).

The next step would be to remove the fuel burning heater module, and check for continuity between pin 13 of the CPM and pin 2 of the heater harness. This is the CPM output to the fuel pump. It should have continuity, if not, the thermal overtemp cutoff switch has failled (burnt / dirty contacts etc).

I'm just going to do some car maintenance myself so will plug in VIDA and play with the heater....

[siapelan]

Originally Posted by SwissXC90

Not quite. "Directly" for me means no connectors or other devices in the path [...] where it goes through the thermal overtemp cutout switch - likely to be a simple bimetal switch contact.

I followed your advice and - bingo! - with a simple bypass of the overtemp cutoff switch the heater works like a charm. The magnetic pump ticking about 2-3 times a second and the heater heating like it is supposed to.

Now I have to do a job to replace the cutoff switch, but at least i know what the problem is.

---- >>>> A follow-up question to be sure I am not doing unnecessary work; I do need to replace it, it is not possible to 'reset' it somehow?

Thank you!