1999 V70 multiple error codes, bad B+

Dodgertom · Post by **Dodgertom** » 01 Dec 2018, 16:53

I've a 1999 volvo v70 xc. Drove it to Farmers' Market, and all was well. Started it up again, and the idle was high, and the car was running rough. It threw 7 engine codes and 1 transmission code. The engine codes were throttle unit communication, speed signal, ecm communication, throttle position signal, accelerator position signal, ecm communication, and control module communication. The tranny error code was control module communication. Does anyone know if there's a connector where all these come together? I hope it's something simple such as that. Thanks.

Post by **rspi** » 01 Dec 2018, 17:44

Sounds like a power supply issue. Check your battery cables.

Post by **abscate** » 01 Dec 2018, 17:53

You need to clear all these codes and see how they come back.

Also, you need the Volvo ECM codes , not the generic descriptions

Dodgertom · Post by **Dodgertom** » 01 Dec 2018, 18:12

Thanks abscate. What I didn't say (trying to be brief) was that after jiggling some connectors (and the two computers), the symptoms went away. I have cleared the codes, but the symptoms haven't returned yet. I will check the battery connections in the morning. The jiggling and the array of codes was what made me think connector.

The codes were: ECM-902a, 510f, e000, 903f, 959f, 912a and 530b; plus tcm-e000. After a while it added TCM-261a, the long-term fuel trim. Thanks again, I appreciate your feedback.

Dodgertom · Post by **Dodgertom** » 06 Dec 2018, 20:25

Found some (only a little) white corrosion on the positive battery terminal. Cleaned it off, and have not had the codes return. Didn't realize that such a small amount of corrosion would interfere with the electronics. Thanks again to abscise and rspi for your help.

Post by **abscate** » 07 Dec 2018, 06:37

Thanks for the follow up!