P2 V70 Misfire on 1,2,3 - bad coil ground bolt Topic is solved

V70IIT5 · Post by **V70IIT5** » 10 Mar 2017, 05:46

I did a heavily laden first 600 mile drive on my new old V70 P2 T5 250bhp, it ran really well, delivered 33 mpg, the only issue being it seems to have drained some coolant into the passenger footwell, although the expansion vessel hasn't dropped much. Yesterday I started up to drive 25 miles and it misfired all the way, it got really bad. The EML came on and started flashing. Today I have plugged in an OBDII reader and it has given me fault codes for:

PO352 Powertrain Ignition Coil B primary/secondary circuit
PO351 Powertrain Ignition Coil B primary/secondary circuit
PO300 Random/Multiple Misfire
PO301 Cyl 1 misfire
PO302 Cyl 2 misfire
PO303 Cyl 3 misfire

I have never seen anything like it. The car started this morning fine from cold, albeit sounding a little rough, then when the temp gauge got 1/3 up it started missing at idle. It was running perfectly at the end of the 600 mile drive. A night in the cold and then this.

It looks like thermal breakdown of the plugs or coils. Please could anyone comment from experience? Thanks

V70IIT5 · Post by **V70IIT5** » 10 Mar 2017, 11:35

Fitted new spark plugs, reset the fault codes, then similar faults reappeared with a rough idle:

PO351 Powertrain Ignition Coil B primary/secondary circuit
P1353 Powertrain Ignition Coil Cyl 2

Post by **abscate** » 11 Mar 2017, 02:20

Your car has a coil fir each cylinder and it sounds like one or more has failed.

We replace all five at 150,000 km and save the old ones as spares

Those codes are also pointing to wiring faults to the coil supply ( common 12vdc to each) so inspect that wiring carefully.

V70IIT5 · Post by **V70IIT5** » 11 Mar 2017, 03:28

Thanks, I found the earth bolt for coils 1&2 loose, I didn't see it before as it was hidden by the oil breather hose jubilee clip. I have cleaned it all and tightened it, it seems fine now. At least the motor got a new set of plugs!

Post by **abscate** » 11 Mar 2017, 04:30

Those bolts are important, they both hold in the coils and ground the HV!

Excellent!

Post by **E Showell** » 11 Mar 2017, 04:47

Coolant in passenger footwell means your heater core is shot. Replace or bypass asap.

Post by **abscate** » 11 Mar 2017, 05:19

Heater core on a P2 isn't fun, I believe climate system has to come out.

Alldata reports 3.5 hours

Post by **vtl** » 11 Mar 2017, 06:25

Steering column, not A/C, has to come out, otherwise the new core will be bent/damaged during installation.

V70IIT5 · Post by **V70IIT5** » 11 Mar 2017, 11:12

This is a right hand drive car so the issue will be removing the glove box compartment. I have seen Robert DIY's method on the LHD cars, he bends the heater matrix out and in. No it doesn't look like fun although I might be lucky in just replacing the O rings on the pipes where they join the matrix....

Post by **vtl** » 11 Mar 2017, 11:18

You're lucky then: going through glove box is way easier than through steering column, brake pedal and CEM.