2001 V70 Crank no Start

[morganbryane]

Ok, I am going to spend some time checking ground wires and contacts. I think I'm going to pull the CEM module from the junction box and clean the circuit board as well. I will update the results when I'm done.

[01_Nautic_V70]

So if the car starts with the relay simulated closed AND you're getting voltage at the relay coil socket, you can rule out the fuel pump and probably the CEM as the culprits. Hopefully it's a simple, low cost fix.

Here's what I think is occurring. The 11.7 volts should be plenty to pull the relay in. Is this measure at the socket with the relay out? If so, what I believe you have is a dirty/weak connection elsewhere in the circuit feeding the coil voltage. Under the load of the coil, voltage is drooping far too low to pull in. This is indicative of a high resistance connection somewhere in series with the coil or a sketchy connection to ground.

Check all connections in the circuit, with special attention to grounds. Unplug and plug back in any connectors. Sometimes, something as simple as an oxidized pin in a connector can cause a problem and reseating the pin can scratch through the oxide layer. If and when you find the culprit, clean up the mating surfaces and apply some dielectric grease to prevent recurrence.

[morganbryane]

So here is my update. I checked all the grounds and they are good. I did go to a junkyard and pulled a CEM out of as same year and model as mine. I know it is supposed to be the same part number for reparing. I installed the CEM to see if it would at least engage the fuel pump relay and it did although it didn't start which I expected. I am planning to send it to have the CEM repaired and programmed in London. Its by far cheaper to have them repair it and pay the overseas shipping than have it done here in the states. Now the instrument cluster isn't working now after reinstalling the orignal CEM so I probably screwed up something else that is going have to be reprogrammed...

[altalake]

Are you sure you're getting voltage to the fuel pump itself? I had a similar problem last year - intermittent which became permanent - on an '01 V70 and thought I had voltage to the pump. I actually only had voltage to the fuel pump sender (easily accessible under the left back seat). The pump's connections are completely within the tank - not easily accessed - and fed by way of that sender. Trouble codes abounded but never anything to do with the fuel system. Pullled & swapped relays, pulled the CEM and cleaned contacts, checked grounds from here to Timbuktu and even found a loose ground but, in the end, the issue was the fuel pump sender unit. About a $100 part online - cost me $1,000 at a dealer who also changed the fuel pump. Gave me a nice Volvo coffee cup, too.

[turbolazi]

The fuel relay is behind the kick panel just below the Steering wheel. There are two torx bots holding the panel on. If you pull the panel off the fuel pump relay is on the last row (ignore the red circle). This pic shows the fog lamp and fuel pump relay on the last row.

As far as my situations, I think need to figure out why when the key is on there is no current to the Fuel pump relay to complete the circuit to provide power to the fuel pump because there isn't going to be any pressure at the rail if the pump doesn't run at key on.

Hi, that is a nice picture of the cem.But sadly I still don,t know what is the fuel Relay?
Call me dumb, but I need help.Please help !
Norbert

[altalake]

Volvo-CEM-fuel-pump-relay.jpg (37.47 KiB) Viewed 3459 times

This should be the fuel pump relay. Do note that most of these relays are exactly the same so you could swap them for troubleshooting.
Xemodex has a video here showing how to remove the CEM - awkward but possible. It might also be possible to remove the relays without popping the whole board out but this would also allow you to look for corrosion - a problem on some cars apparently from windshield leaks.
http://xemodex.ca/ca/knowledgebase/cent ... e-removal/

[Oka]

Cleaning the hot plate and wire with MAF cleaner fixed the fouling. I plugged it back in and also found the tube in the downstream side of the sensor to be barely on. Likely a leak. Tighten it all up and it purrs like a kitten again. No hunt or pulse anymore. No CEL generated.

Hello, currently, am having a similar issue with my XC. Would you please clarify what these really are?
1. "the hot plate and wire with MAF" - What "hot plate"?
2. "the tube in the downstream side of the sensor" - You mean the lower end of the turbo hose?

Thanks

[01_Nautic_V70]

The hot plate is the actual sensor in the MAF. It works by heating a metal plate. The air across it cools it. By knowing heat input, ambient temp and plate temp, air flow can be calculated reliably.

Cleaned this by spraying down with some MAF cleaner. Don’t touch it. Finger oils will foil it and cause premature failure.

The hose down stream, if I recall, is where the EVAP system hooks into inlet air. It’s a small (1/2”?) rubber hose connecting just past the Air cleaner and well before the turbo inlet.

[Oka]

The hot plate is the actual sensor in the MAF. It works by heating a metal plate. The air across it cools it. By knowing heat input, ambient temp and plate temp, air flow can be calculated reliably.

Cleaned this by spraying down with some MAF cleaner. Don’t touch it. Finger oils will foil it and cause premature failure.

The hose down stream, if I recall, is where the EVAP system hooks into inlet air. It’s a small (1/2”?) rubber hose connecting just past the Air cleaner and well before the turbo inlet.

I already have a new Bosch MAF.
I will verify the hose you mentioned.
Thanks you so much for the information.