Check engine light with no code

Golden86 · Post by **Golden86** » Mon Apr 10, 2017 6:42 pm

96 Volvo 850 Turbo automatic motronic 4.3

I have had a persistent check engine light with no codes that I can pull with an OBDII reader. I clear it and it comes back after a few miles of driving. I was able to make a a led/switch to read the flash codes off my ecu, and they show 1-1-1. The only code I'm getting is from the vol-fcr and reading the cluster codes. It is showing code C1-221 (vehicle speed signal missing). Can the cluster throw a check engine light for this code? If so, how can I test it?

Any help would be greatly appreciated.

Thanks

Post by **MadeInJapan** » Mon Apr 10, 2017 8:31 pm

Speed missing is when you haven't driven 35mph yet- it comes up on all cars. You sure this isn't the service light and that just needs resetting (of course after you change your oil).

Golden86 · Post by **Golden86** » Tue Apr 11, 2017 4:06 am

not service light, definitely the check engine light

Sommerfeldt · Post by **Sommerfeldt** » Tue Apr 11, 2017 9:15 am

Did you read the codes from the transmission? The tranny can call the ECU to light up your christmas tree if it wants to. The codes can be hard to read on M4.3, and even harder to reset sometimes, but if the ECU doesn't give you a code, the transmission is probably the next stop I'd make.

- S

Golden86 · Post by **Golden86** » Tue Apr 11, 2017 1:15 pm

No codes from the trans via vol-fcr.

Golden86 · Post by **Golden86** » Sat Apr 15, 2017 2:12 pm

Quick update for anybody who may have the same issue. I wanted to make sure the ecm is throwing actual codes, so I pulled the MAF sensor and tried reading the codes again. This time the MAF error came up on my OBD2 reader, so I know that works. I also read the codes through the flash tool, the MAF code popped up, and one more code, Rear O2 low voltage.

Replaced rear O2 and the code never came back. This just shows how finicky the volvo can be, make sure to check all your avenues.