Volvo Owners Club Forum - View Single Post - What's the P80 850 V70 S70 C70 Killers & Std. Faults

acshortt5 · Feb 27th, 2017, 14:14

Some more common faults for you:

MAF sensor - if it fails you probably can't start the car and it will be chucking black smoke (unburnt fuel) out the exhaust. Unplugging it will default the ecu to a set table of fueling and let the car run to get you home.

Cam position sensor. If you are replacing this then also budget for the cam seal which is probably leaking and the cause of the failed sensor. Volvo also do uprated (higher tensile) bolts (2 x bolts) for this now so get those as well.

Thermostat bolts - the originals are prone to snapping & volvo now do higher tensile ones.

Coolant temperature sensor - Can lead to non/difficult starting and poor mpg. Get a volvo one for this, an aftermarket one gave faulty readings and was a poor (leccy connector) fit. They changed the sensor several times during the P80 cars run so take care when ordering - volvo is safest for this.

Immobilizer anntenna ring - can fail leading to the car cutting out after starting. You can try and clean the contacts but a new one is only circa £35 and 10 minutes to swap.

Ignition switch - when it fails it can cause warning lights to appear on the dash and speedo/rev counter to not work. If you turn the key slightly back and forth and the lights go out/things alter then that is the issue. About £40 from volvo and fairly easy to change. Keep the receipt though as a replacement failed on me after a week!

Aux power - the little connector (with 4 red wires bunched together) on the top of the positive (+ve) lead on the battery. If this comes loose you can have the engine cut out randomly (every time you go over a bump basically) and was a sod to try and fault find as I checked everything else before getting there and no fault codes were stored. Check the contact surface is clean and the nut tightened.

Autobox PNP switch - When this stops working properly common things are your reverse lights don't work without pushing/pulling the selector. Can lead to non starting in N (neutral) or not at all. It's a fair bit of work to get in there, repair kits are available to replace the contacts but personally I had volvo sort it with a volvo part.

Feb 27th, 2017, 14:14	#16
acshortt5 Volvo Nutcase Last Online: Jul 14th, 2023 12:57 Join Date: May 2007 Location: N/A	Some more common faults for you: MAF sensor - if it fails you probably can't start the car and it will be chucking black smoke (unburnt fuel) out the exhaust. Unplugging it will default the ecu to a set table of fueling and let the car run to get you home. Cam position sensor. If you are replacing this then also budget for the cam seal which is probably leaking and the cause of the failed sensor. Volvo also do uprated (higher tensile) bolts (2 x bolts) for this now so get those as well. Thermostat bolts - the originals are prone to snapping & volvo now do higher tensile ones. Coolant temperature sensor - Can lead to non/difficult starting and poor mpg. Get a volvo one for this, an aftermarket one gave faulty readings and was a poor (leccy connector) fit. They changed the sensor several times during the P80 cars run so take care when ordering - volvo is safest for this. Immobilizer anntenna ring - can fail leading to the car cutting out after starting. You can try and clean the contacts but a new one is only circa £35 and 10 minutes to swap. Ignition switch - when it fails it can cause warning lights to appear on the dash and speedo/rev counter to not work. If you turn the key slightly back and forth and the lights go out/things alter then that is the issue. About £40 from volvo and fairly easy to change. Keep the receipt though as a replacement failed on me after a week! Aux power - the little connector (with 4 red wires bunched together) on the top of the positive (+ve) lead on the battery. If this comes loose you can have the engine cut out randomly (every time you go over a bump basically) and was a sod to try and fault find as I checked everything else before getting there and no fault codes were stored. Check the contact surface is clean and the nut tightened. Autobox PNP switch - When this stops working properly common things are your reverse lights don't work without pushing/pulling the selector. Can lead to non starting in N (neutral) or not at all. It's a fair bit of work to get in there, repair kits are available to replace the contacts but personally I had volvo sort it with a volvo part. __________________ Andrew 1998 S70 T5 CD AUTO Previously a 1990 240 GLT-R Last edited by acshortt5; Feb 27th, 2017 at 14:26.