2005 V70 loses power codes for cam and fuel

IslandV70 · Post by **IslandV70** » 03 Jan 2019, 15:04

My new-to-me 2005 V70 2.4 liter keeps getting a CEL for P0026 (intake valve solenoid) and P0190 (Fuel Rail Pressure Sensor A Circuit). Twice now the car has briefly lost power like the engine could only idle. A restart fixed it both times.
I did not have the scanner on the car either time, but here is the result today:
Most of the time the fuel pressure is around 50-58 PSI or so and had a kind of jiggly graph. It will every now and then go to 80+ pounds and stay here in a flat line for 5 to 30 seconds.
Is the pressure actually doing that or has the sensor gone nuts? Why is this occasionally resulting in no power?
Is the cam sensor a totally unrelated thing? Is this stuff normal on a car with 59,000 miles?

Post by **precopster** » 03 Jan 2019, 20:20

Replace the fuel pressure sensor. They often go bad. A rise in detected fuel pressure to 80psi will cut power to the fuel pump momentarily to compensate; hence the lack of power.

The cam code is another issue. Check cam timing carefully and check the ambient temp tension setting when checking it.

IslandV70 · Post by **IslandV70** » 04 Jan 2019, 06:54

Thanks! The car has 59K and the timing belt was changed in 2015 by a Volvo dealer. I hope they got it right, but maybe not. The CEL is not always on, if you clear it you can drive for several days before it comes back. Is it possible the cam solenoid itself is going bad? That looks easy enough to replace compared to retiming the engine.

EngineeringBloke · Post by **EngineeringBloke** » 04 Jan 2019, 09:53

You may not need to replace the solenoid - just clean it. In January, this year, I had a similar cam error for my exhaust side for a couple of weeks - P0027 Exhaust Valve Control Solenoid Circuit Range/Performance (Bank 1). My car is a 06 S60 2.5T. I have been using synthetic oil for years.

Following some instructions on Swedespeed, I cleaned the oil channels in the solenoid, and I replaced the solenoid gasket. I do not recall what I used for the cleaning, but after putting it back together, the error was not seen since.
https://forums.swedespeed.com/showthrea ... t-or-clean

Oragex and vtl have some great pictures including a disassembled solenoid:
viewtopic.php?t=71557

And I just found a Volvo service bulletin for cleaning VVT solenoids 2001 - 2006
https://volvo.oemdtc.com/154/vvt-soleno ... 2006-volvo

After removing from the engine, I pulled the solenoid from its housing (see either of the 2 links above), but did not disassemble further. I did NOT need to remove the snap ring or try to access the plunger (4) in the Volvo cleaning notes.

IslandV70 · Post by **IslandV70** » 04 Jan 2019, 09:55

Well so far this is all good news, these parts are on top of the engine

(I just had to fix my wife's O2 sensor on her Avalon and it is buried beyond the reach of any human)

IslandV70 · Post by **IslandV70** » 04 Jan 2019, 09:56

Oops - forgot to ask:
Is the fuel pressure *actually* at 82 PSI or does the sensor just think it is? Should I get a fuel pressure gauge?
Thanks all!

EngineeringBloke · Post by **EngineeringBloke** » 05 Jan 2019, 09:40

Although the fuel pressure fluctuates a little, it is very unlikely that it drops from 82 down to 54 so fast. The reading just does not look real. It is almost certain that there is an issue with the sensor, or possibly with the wiring from it.

Note that the P0190 is one of several FPS error codes and it is a bad circuit, not the pressure high, low or inconsistent. However, reports show the issue fixed with FPS replacement so the symptoms appear related to a bad sensor that results in an invalid output signal.

Removal of the sensor requires releasing fuel pressure and capturing some fuel from the valve on the fuel rail. Also undoing the FPS torx bolt may be tough.

This page suggests an issue with 2004 Volvo v70 FPS units - not your year but interesting.
viewtopic.php?f=31&t=63777

IslandV70 · Post by **IslandV70** » 05 Jan 2019, 09:44

That is what I thought - The pressure readings I am seeing are not real, but a malfunctioning sensor. I think I will get a new one.

EngineeringBloke · Post by **EngineeringBloke** » 05 Jan 2019, 09:55

Another comment.

I am puzzled. If the sensor says high, then the pump stops, even if the pressure is normal. But the pressure will then fall as fuel is used, and not replaced by the pump. Once the sensor reports true pressure levels, I would expect it to report low pressure, but from your screen prints, it picks up in the low 50's where it continues. This is odd to me.

Perhaps the ECM is able to run a default pump cycle and keep a decent pressure.

I still think sensor replacement is the right next step.

P0190 is one of several FP Sensor codes, and it represents a signal failure.

P0087 – Fuel rail pressure sensor or rail pressure too low
P0088 – Fuel rail pressure sensor or rail pressure too high

P0190 – Fuel rail pressure sensor circuit open/short/failure

P0191 – Fuel rail pressure sensor circuit performance/range
P0192 – Fuel rail pressure sensor circuit low input
P0193 – Fuel rail pressure sensor circuit high input
P0194 – Fuel rail pressure sensor circuit intermittent

IslandV70 · Post by **IslandV70** » 06 Jan 2019, 11:29

Car goes back to the dealer Tuesday. We'll see how that goes.