1999 S70 ignition coil compatible with 2008 S60?...mis-fire and PO301

volvooh · Post by **volvooh** » 02 Jun 2019, 18:16

2008 Volvo s60. 137,xxx mi. Son was driving this morning. Started to mis-fire. Pulled off at a friends and I came up with a code reader. Also grabbed a spare coil out of a 1999 Volvo S70. Scanned P0301. Replaced the coil with the one from the 1999, started and ran smooth. Traveled about 10 mi and started missing again.

Just for kicks R and R the coil, no luck. Installed the old one, no luck. This is all parking lot diagnostics BTW. Planning to swap coils with other cylinders to see if the code follows tomorrow. Any thing else I should be looking at?

Also, had heavy rains the night before. Any chance any sort of water incursion could be an issue?

Post by **abscate** » 03 Jun 2019, 08:23

Have a good look at the 12V coming into the coil - its a common, but we are getting more reports of these wires going bare on P80 and short faults.

I think the coils changed from late P80 to P2 though? Not sure if that is clouding the fault finding.

The 10 minute cure sort of implies more wiring fault than a coil fault

volvooh · Post by **volvooh** » 03 Jun 2019, 14:15

Not what I wanted to hear! I was hoping for an incompatible coil! I will let you know what I find out.

Post by **oragex** » 03 Jun 2019, 17:39

Water near the coils kills them - they are actually often times not sealing the plug hole from water. Look with a flash light inside the hole for water round the spark plug. Worth pulling them, wipe dry and also check the plugs, worn ones will cause the coil to fail

volvooh · Post by **volvooh** » 04 Jun 2019, 05:11

Thanks. I was able to move the coil twice and misfire code followed it. Interesting though I managed to get a mis-fire on coil 3 the first move and number 4 the next. Never touched those though. I moved the suspected bad coil to the number 2 then the number 5 respectively and the code followed it.

volvooh · Post by **volvooh** » 04 Jun 2019, 06:57

Oragex. Thankfully no water appeared to enter the sparkplug coil area. I am going to have to assume a defective coil at this point. May just replace the entire set to be sure.

Post by **oragex** » 04 Jun 2019, 10:48

My take on this is to replace only the faulty coil, then keep a spare coil inside the trunk along with 1-2 tools to replace on the road. Usually only 1-2 go bad. Important to buy the Bosch or Beru ones (fcpeuro.com). To find a faulty coil without a code reader, just unplug each one at a time, the one where the engine doesn't drop the rpm is the bad guy.