Start prevented try again, again

SVO LOU · Post by **SVO LOU** » 03 May 2019, 19:57

Guys,
Bought a non-running 03 xc70 to see if I can get it running for a daughter about to start driving in a few months.
According to the previous owners the car has always been a dream but one day they were driving, came home and car wouldn't start again, currently shows "Start Prevented, try again".
There's only one key and fob and I've tried locking/unlocking 5 times to reset the immobilizer with no help. I have another identical model car and swapped antenna rings and other car still runs and this one still won't crank.
Any other ideas for me to try? I can physically swap the CEM if anyone thinks it'll help but don't know if it has to be re-programmed.
I'm not getting any DTC codes with a foxwell uni-directional scanner I have.
Thank you.

Post by **RickHaleParker** » 03 May 2019, 23:06

They will do that if the battery voltage is too low.
What is the battery voltage?

Post by **oragex** » 04 May 2019, 03:45

Maybe the antenna ring? Also make sure the battery is charged, alternator is charging fine, all power cables are tight without cracks

Post by **abscate** » 04 May 2019, 06:09

DOes start inhibit on P2s stop cranking or result in a crank no-start condition, like P80s?

SVO LOU · Post by **SVO LOU** » 04 May 2019, 18:30

RickHaleParker wrote: ↑03 May 2019, 23:06 They will do that if the battery voltage is too low.
What is the battery voltage?

Battery voltage is 12.3 but drops to 11.75 when the key is put in position II, guess from the headlights, taillights, and some interior lights on from having the doors open.

oragex wrote: ↑04 May 2019, 03:45 Maybe the antenna ring? Also make sure the battery is charged, alternator is charging fine, all power cables are tight without cracks

Antenna ring was swapped but no difference.

abscate wrote: ↑04 May 2019, 06:09 DOes start inhibit on P2s stop cranking or result in a crank no-start condition, like P80s?

Sorry, I should've been more clear. When I turn the key to start I hear the fuel pump prime but it doesn't attempt to crank.

In fact, if I charge the battery with the ground terminal off the battery, I insert the key and turn it to POS II and as soon as I re-connect the battery terminal the "Start prevented try again" shows up on the DIM.

Post by **RickHaleParker** » 04 May 2019, 18:47

SVO LOU wrote: ↑04 May 2019, 18:30 Battery voltage is 12.3 but drops to 11.75 when the key is put in position II

Battery is flat dead, 0% charged. Try a known good battery. No sense in doing anything else until this is dealt with.

I suspect the battery has been the problem all along. Focus on the battery.

In fact, if I charge the battery with the ground terminal off the battery, I insert the key and turn it to POS II and as soon as I re-connect the battery terminal the "Start prevented try again" shows up on the DIM.

How are you determining that the battery is taking a charge and what it's State of Charge (SoC) is?

A flat dead battery on a 6A charger would take at least 48 hours to charge, If it does take a charge.
I have brought batteries back from 0%, sometimes it took weeks on the charger. Other times it never happens.

Post by **oragex** » 04 May 2019, 19:22

As above, try a new battery but also make sure quickly if the alternator is charging it properly. You should see at start up in the morning some 14.5V with the engine at idle - it may drop later on once the battery has been topped.

A well charged battery will be near 12.7V, however this should be measure with the engine and all lights and computers off - this car takes exactly 10 min. to shut off all computers after the key has been removed from the ignition www.youtube.com/watch?v=VsrmpXpZGVs

The next test would be to measure the battery before parking the car, then again the next morning before starting it, and see if the voltage has dropped overnight (= parasitic drain)

SVO LOU · Post by **SVO LOU** » 04 May 2019, 21:17

I'll definitely swap in the battery from the other volvo tomorrow and see what happens but from what I've always seen a battery is usually around 12.3V without the vehicle running and about 14.3V when it is. I've been slow charging it (2A) for today only but will try it for longer.

Also, I don't think the alternator is a factor yet since the car won't crank but I guess it could be if it's internally shorted and draining the battery?!?!?!?

Post by **RickHaleParker** » 04 May 2019, 21:52

SVO LOU wrote: ↑04 May 2019, 21:17 I've been slow charging it (2A) for today only but will try it for longer.

At 2A it should take at least a week to fully charge from 0% SoC.
The theoretical minimum time is 80 hours @2A for a 160 amp-hour battery but it never charges that quick.
2 amps * 80 hours = 160 amp - hours.

1. Connect battery to charger, let it charge until the charger reads full charge.
2. Disconnect battery from charger for 15 minutes.
Repeat steps 1 & 2 until take it does not take much time to reach 100%

SVO LOU · Post by **SVO LOU** » 05 May 2019, 19:13

After your post I let it charge at 2A overnight then switched it to 6A for half the day then, between one of many tasks on the honey-do list, I swapped batteries. The battery I've been charging, from the no-start car, cranked up the car that already starts. The battery from the car that starts still wouldn't start the car, still shows "Start Prevented try again" when the ignition is turned to position II, before I even attempt to crank it.
Guess I'm still in the same boat...Aargh.