My 98 V70 (287,000 miles, NA) died while I was driving on a local road with no warning (no sputtering, etc.) and I can't get it to start. I can hear the fuel pump prime when I turn the key and I have pressure at the fuel rail. The starter turns the motor and I can see the camshafts rotate. I pulled the coil wire leading to the distributor and I don't get a spark.

I checked the coil, camshaft position sensor connector, and crankshaft sensor by following Chilton and various posts here and on other sites.

1. Coil has proper resistance for both the primary and secondary winding test and has proper voltage at the leads.
2. Crankshaft sensor has correct resistance (I posted incorrectly that I thought I had mis-measured the resistance and it was, in fact, bad. Remeasured today and realized I was using the wrong scale so the resistance is good - 312 ohm)
3. Camshaft position sensor connector has the correct voltages and resistance at the terminals. I swapped the cam sensor out for a wrecking yard one but it made no difference.
4. There is continuity between cam sensor connector pin 2 and pin A21 in ECU
5. The light for winter mode is lit on the mode selector buttons even if it is in sport or economy mode when I turn the ignition on
6. The only OBDII code was for a coolant temperature sensor that has been bad for some time but the 'check engine' light turned off recently anyway. I changed the sensor but it made no difference
7. I can feel the main relay 'click' when the ignition is turned to position 2

This is the first time I've been at a complete loss as to what to do next. Any suggestions? Does the tranny mode 'W' light mean anything?


Thanks,
Kelly

 

My first instinct is cam or crank sensor, I have tested them before and came up good and replaced with new and it fixed the problem. I had a Lincoln Mark VIII that died on me, tested cam sensor and it was good. Went to the store and bought a cam and crank sensor anyways. Replaced cam sensor and it started right up. I also replaced the crank sensor as I have always felt that when one goes the other isnt too far behind. Just my .02

 

Thank you for your response. I should have updated this post with the resolution but since there had been no responses I didn't know anyone was taking an interest in it. Long story, but after putting in a new ECU it fired right up - and ran 2 miles until it did the exact same thing! Ended up going through about 4 ECUs as each time I thought I'd fixed the problem I hadn't. I finally pulled the whole engine compartment wiring harness and found areas where the insulation had worn completely through (see picture) due to long-term abrasion. There were obvious signs of shorting so I wrapped each wire where I found the missing insulation and the car has gone around 300 miles with no problems.

 

Glad to hear you got her fixed

 

Had I seen this back when you first posted it, after reading the symptoms and diagnosis you mentioned, the wiring harness is exactly what I would have suggested to you to check. I am surprised that no one posted a response to this as it is a known but not often talked about issue that is subject to failure with these models and other Volvo cars. I have had to do some kind of wire harness repairs on every Volvo I have owned during the past 30 years, including the 98 V70 GLT that I now drive daily.

 

Where were these wires located at?

 

They are part of the wiring harness that runs from the ECM and TCM box on the passenger side of the engine compartment across the compartment along the crossmember with parts branching off along the way for various sensors and controls. It's inside a covered plastic tray to protect it but the tray has a tendency to fill with grit and grime over time. The particular section that had the bare wires was were the tray makes a bend as it connects with the crossmember. The arrow in the picture points to part of the tray.

 

So that was 1/2 way across the motor behind/under the radiator??? Great find, that is nuts.

 

Were the ECM's actually ruined by this? Have you swapped them around since?

 

Thanks. I have to say I found some mention of this problem in another post that I can't find anymore but at the time I had no idea where the harness ran in the engine compartment. I took out the fan and shroud to make a lot of space to access the part on the crossmember. All of this convinced me it was time to get another car - a 2006 S40 T5 AWD manual - but I still have the V70.


I haven't swapped them myself but the shop I had it in about half way through this ordeal did and said it wouldn't run with one of the old ECMs but would with a new one. I poked around in two of them but couldn't find anything obviously wrong. They may be fixable but I don't have the time to investigate further.