Volvo 850 Transmission error codes
 

Our 95 Volvo 850 non turbo is in limp-mode where it does not engage the lower gears. Giving that orange arrow flashing light.

Got some error codes from the OBD1:

A1 -- Transmission

124 Mode selector faulty or short circuit to ground

114 Program selector open circuit or short circuit to supply

122 Solenoid S1 open circuit


A2 -- Fuel System

121 MAF sensor signal


Replaced the NSS switch/PNP switch with a known (used) working one but it didn't change anything.

The MAF sensor was also replaced early this year with a new one and then switched out with another new one (warranty replace) because the CEL remained and the same code was produced.

Any ideas what the problem could be?

symptoms still seem to point to the PNP - if you are sure the replacement part is good, next step would be to look at the connectors and wiring for any chafing, corrosion etc.

I read on a Volvo forum that you have to reset the CEL after installing the PNP in order to reset the limp mode. Tracking down an OBDII to perform reset. Tried to reset with the on board OBDI but it would not engage (OBDI does generates codes). Tried disconnecting battery and holding down horn for 1-2 minutes and that didnt work either.

The local Napa will hook up and scan OBDII but they wont clear the codes. They claimed it was illegal to clear engine codes. Pff!

Will acquire an OBDII to further perform diagnostics; clear codes, test drive...

In answer to mt6127's reply; I read on another forum that it could be dodgy connections in the multi-plug that carries the electrical connections to the gearbox. So next step is to disconnect, spray cleaner in and reconnect the two multi-plugs in front of the gearbox. Another tip that might work is to disconnect the battery, then remove the TCM and the ECU. Clean the contacts with rubbing alcohol and a small brush and re-insert both modules.

Im a MCSE guy with no automobile experience. All help is appreciated!