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1999 v70 - Check Engine Light - Car Computer Cannot Be Read

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

rivera0608
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1999 v70 - Check Engine Light - Car Computer Cannot Be Read

Post by rivera0608 » Mon Jul 15, 2019 11:26 am

My check engine light has been on for a while. Took it to AutoZone to have the codes read: "Cannot establish a connection with the car". Tried three computer code readers, same error. Guy told me it might be a bad ground. I cleaned off three grounds I could find in the engine, as well as the battery terminals. Start up the car, and the check engine light was off and stayed off for about 2 weeks. Now it's back on, when back to AutoZone, same deal. Can't read the computer.

Anyone have this happen to them before? Thanks for any advice!



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Re: 1999 v70 - Check Engine Light - Car Computer Cannot Be Read

Post by abscate » Mon Jul 15, 2019 11:37 am

rivera0608 wrote:
Mon Jul 15, 2019 11:26 am
My check engine light has been on for a while. Took it to AutoZone to have the codes read: "Cannot establish a connection with the car". Tried three computer code readers, same error. Guy told me it might be a bad ground. I cleaned off three grounds I could find in the engine, as well as the battery terminals. Start up the car, and the check engine light was off and stayed off for about 2 weeks. Now it's back on, when back to AutoZone, same deal. Can't read the computer.

Anyone have this happen to them before? Thanks for any advice!
You cleared the codes temporarily when you disconnected the battery. IF they took two weeks to come back, its probably a minor evap system fault.

The code reader comes direct from the ECM so if there isn't a wiring fault, thats pretty much it.

Are you a turbo 1999 (BOSCH engine management) or non turbo (DENSO) on your 1999?
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Re: 1999 v70 - Check Engine Light - Car Computer Cannot Be Read

Post by rivera0608 » Mon Jul 15, 2019 12:35 pm

Turbo 1999.

What's the repair cost looking like to get the EVAP system checked/fixed?



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Re: 1999 v70 - Check Engine Light - Car Computer Cannot Be Read

Post by abscate » Mon Jul 15, 2019 12:48 pm

rivera0608 wrote:
Mon Jul 15, 2019 12:35 pm
Turbo 1999.

What's the repair cost looking like to get the EVAP system checked/fixed?
Usually one or two fairly cheap hoses ($50-100) and 2 hour labor - but the problem will be when you come up for inspection, if the Ocean State requires OBD compliance, the lack of comm with the ECM (car computer) will fail you.

From the RI DMV website
Communication
If the vehicle's OBD system is not communicating with the inspection analyzer do to a vehicle defect it is cause for failure.
About Readiness
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Re: 1999 v70 - Check Engine Light - Car Computer Cannot Be Read

Post by rivera0608 » Tue Jul 16, 2019 7:54 am

Damn, well it's not up for inspection until 08/2020 so I have some time to deal with it.

So the evap system fault is causing the Check Engine light...what could be causing the lack of communication with the ECM?



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Re: 1999 v70 - Check Engine Light - Car Computer Cannot Be Read

Post by abscate » Tue Jul 16, 2019 10:57 am

rivera0608 wrote:
Tue Jul 16, 2019 7:54 am
Damn, well it's not up for inspection until 08/2020 so I have some time to deal with it.

So the evap system fault is causing the Check Engine light...what could be causing the lack of communication with the ECM?
Im guessing at the EVAP by the fact that it took 2 weeks to come back. You really want to get the comm problem solved rather than throw money at the EVAP.

Have you tried reading with the ignition off, turned on, and engine running? (all three)


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Re: 1999 v70 - Check Engine Light - Car Computer Cannot Be Read

Post by misha » Tue Jul 16, 2019 1:25 pm

It could be as simple as a blown fuse(cig.lighter should use the same)...K-line or Immobiliser ecu,since K-line for ECU ONLY goes through immobiliser.


'97 850 2.5 20v /fully equipped/ Motronic 4.4 / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
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Re: 1999 v70 - Check Engine Light - Car Computer Cannot Be Read

Post by rivera0608 » Wed Jul 17, 2019 11:43 am

abscate wrote:
Tue Jul 16, 2019 10:57 am
rivera0608 wrote:
Tue Jul 16, 2019 7:54 am
Damn, well it's not up for inspection until 08/2020 so I have some time to deal with it.

So the evap system fault is causing the Check Engine light...what could be causing the lack of communication with the ECM?
Im guessing at the EVAP by the fact that it took 2 weeks to come back. You really want to get the comm problem solved rather than throw money at the EVAP.

Have you tried reading with the ignition off, turned on, and engine running? (all three)
I had a buddy of mine at work try his code reader just a short while and ago, and it was a no go on all three (ignition on/off, and engine running). I'm going to double check the fuses like the other poster "misha" mentioned. Also going to try and remove the e-brake cover to try and get at the underside of the OBD-II plug and see if the actual plug is the issue.

I'll report back with our findings.



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Re: 1999 v70 - Check Engine Light - Car Computer Cannot Be Read

Post by rivera0608 » Fri Jul 19, 2019 1:35 pm

So still no go on the ECM communication. Doubled checked the fuses too. I found a pinout diagram for ISO protocol and I'm going to check the data wires to see if they are corroded in any way. I'm assuming the power and ground wires should be fine since the diagnostic computer gets power when I plug it into the OBD2 plug.

Do you know where I could buy a replacement plug and pigtail wire? I found the receptacle housing part (https://parts.volvoofnorthmiami.com/p/V ... 49549.html), but I can't find the proper wiring components.



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Re: 1999 v70 - Check Engine Light - Car Computer Cannot Be Read

Post by misha » Fri Jul 19, 2019 3:00 pm

misha wrote:
Tue Jul 16, 2019 1:25 pm
... ...K-line or Immobiliser ecu,since K-line for ECU ONLY goes through immobiliser.
K-line is communication line for ECU.


'97 850 2.5 20v /fully equipped/ Motronic 4.4 / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

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