I am a new member since 11/05. I own a 1998' S70 and a 2000 C70 LPT. I have used this forum from time to time to help with volvo problems and it has been a great. The problem I have now is with my C70. And I really take time and have patience when it come to car repair and particularly with check engine matters because as we all know things are not always the way they seem when it come to check engine lights. The symptoms are, car is sluggish, the engine hunts at idle between 400 and 900 rpm sometimes, it has cut off 3-4 times when near idle before, no RPM's when accelerator is pressed. This is how it started in order:
1) check engine comes on. Code is read. PO101 Mass air flow meter or VAF & PO172 Bank one system too rich. Had codes turned
off. Will wait for the next check engine light.
2) Approx. one week later check engine comes on. Oxygen sensor. Turned code off.
3) Car is running rough at idle sometimes. Hunts up and down between 400 - 900 RPM. I have put in premium fuel 2 - 3 tankfulls. No
changes.
4) Car has cut off 3 - 4 times.
5) Now I noticed when idling the car will not accelerate when the accelerator pedal is pressed. It does not always do this and I
eventually figured that when it does this it only does it when the brake pedal is pressed. When this happens if you have the
accelerator pedal and the brake pedal pressed at the same time no RPMs or acceleration is realized, once you let off the brake
pedal the car will accelerate normally.

FYI - the electronic throttle control was replaced approx. 20K miles ago.

I have not had the check engine light come on in 2 - 3 weeks. I really don't know which way to go and don't want to start replacing expensive things. Help.

Thanks in advance, Guy

 

Ok start again by having the codes pulled. Because the light isn't on doesn't mean there isn't codes.

When there is emmissions codes the computer goes into a Limp Home mode.
Is disables stuff O2 sensors, Missfire Diag, It also Disables what you are talking about. No throttle response when the Brake Pedal is depressed. That is done by the computer.

Have the codes pulled and let us know what they are.

If the car won't idle or run try unplugging the Mass Flow sensor and see if it will Idle. If so then the Mass Flow sensor is bad.

 

Ok Tech. I will try these things and keep you posted. Thanks for the quick reply.....

Guy

 

Ok, I had the codes pulled again today at Advance Auto. No check engine light on, however there was one code present(PO101) Mass Air Flow sensor CKT range or Vane Air Flow sensor. I had the code erased and the car seemed to run better. I then unplugged the Mass Air Flow Sensor and the car started running with similar symptoms as before, I.E. rough hunting idle, no throttle when brake is pressed, etc....
I had checked before and Advance has a remanufactured Mass Air Flow Sensor by Cardone for a 2000 Volvo C70, $108.60/exchange.
I asked if any software has to be loaded once you make the swap and they said no.

TECH or anyone - let me know what you think.......... Should I go this way?

Thanks again in advance.

 

I would go with the Volvo MAF sensor. I think I paid $180 for it for my V70.

 

AGREED

 

Ok, thanks I will try this.

Guy

 

Just had a MAF installed in my c70 in January. Cost: $232.70. Installation: $373.99. It was done under warranty but that is apparently what the dealer charged back to the MFG.
R.

 

Ok, I replaced the Mass Air Flow sensor and erased the codes. Car ran Ok for 1 - 2 days then similar symptoms as before started happening and the "Check Engine" light comes on. Now I have two codes. These are the codes:

1) P1655 - Manufacturer control auxiliary inputs and outputs
2) PO172 - System too rich bank one

Anyone please advise....

Thanks in advance, Guy

 

That is most likely Throttle body codes now.

 

So the Throttle body was replaced approx. 1 year ago (20K miles) at the dealer. Is there any recourse? Warranty?

Guy

 

Took car to the dealer with these problems on 3-15-06. They read several codes and cleaned:

ECM 644A - Camshaft reset valve(timing is controlled here) They cleaned it.
ECM 130A - Air leakage intake aftermarket MAF sensor (within range)
ECM 6440 - Battery low, 11.48 volts , my battery is only a few months old and this is likely because the car was having intermittent
trouble starting from the problems I have been experiencing.
Crankcase slightly blocked - clean
Clean Throttle body Module.
Changed oil and filter.

Costs of $263.

On 3-16-06 the check Engine light comes on again. Took car to Advance auto at 8:00 PM. Eight codes now:

P1655 - Manufacturer control auxiliary inputs and outputs
PO445 EVAP - Emissions control system purge valve "C"
PO448 - Vent curcuit short
PO245 - Turbo Wastegate Solenoid A low
P0031 - HO25 Bank 1 sending unit heat curcuit low
P0037 - HO25 Bank 2 sending unit heat curcuit low
P0014 - Camshaft position Actuator B bank one timing over advanced
P0136 - O2 sensor curcuit malfunction, bank one sensor 2

I am really at a loss on where to go now so if anyone can help, please do. This is going from bad to worse.

Thanks in advance, Guy

 

I wish I could give you more advise. It sounds like you might have bad O2 sensors.

Have you had the timing belt replaced on it?

I would call the dealer back and tell them the light came back on already.

The p-codes really don't give all the info. (The bad part)

 

Has anyone considered the possibility of a failed ETM? Don Wilson at vexedvolvo.org reports the current replacement part is failing as early as 7,000 to 12,000 miles.

 

The timing belt has not been replaced yet. I did have the car back at the dealer. After today the dealer is stumped. They tried to reset the module and erase the codes and couldn't. They had cleaned the ETM before. If it is failing it is hard to point to that at this point. The car does run better, about the only thing at this point is the "Check Engine" light glaring in you face with the thought every time looking at it knowing there is eight codes present in there and some slight missing under heavy load when you floor it. I will keep you posted.

Guy [:@][:@][:@][:@]

 

The VVT valve could be bad causing some of the problem.

And possible the O2 sensors.

 

Tech,
What is the VVT valve? What does it do? Location? Any way to test it?

Is there any one of the two O2 sensors that go bad more than the other? How should I isolate one from the other other? At this point I do not have a lot of confidence in the codes, however I don't know if I have much choice. This is leading down the "path of replace and wait to see what else happens". Please advise.

Thanks for your continual help.

Guy

 

The VVT valve is bolted onto the Cam cover under the Black cover on the top of the engine. That is what the dealer sayed they cleaned. The controls oil pressure to one of the Cam pulleys and controls timing advance and retarding.

The only real way to test the items would be to have a good program/Scanner to monitor the items with the car running.

 

Ok, thanks.

 

Ok, more to this story. Had the car back at the dealer for 4 days. They ended up finding the emissions fuse burned. They replaced that and I took the car home. Still had a slight miss under load but no lights. Took it back and had the codes pulled. Here they are:

P1655 - Manufacturer control auxiliary inputs and outputs
P0014 - Camshaft position Actuator B bank one timing over advanced
Cylinder # 3 misfire

So I took the cover off the top that exposes all the HD wiring. Checked for bad wires, plugins, etc... Ended up finding both wires from the Camshaft Position Sensor had the insulation pinched through from where the cover was put on before. The wires apparently were not put back properly before thus causing the insulation to be pinched. So I taped them well and buttoned it up. Took a test drive and the "miss" is gone so I believe it was shorting out under load. Its hard to say what the real contributors were but I have had these ongoing problems for about 6 - 7 weeks now. I will have the codes read again tomorrow to confirm if all is well.


Guy