I have a 850 T5-R and when on the motorway the up arrow flashes suggesting gearbox fault I have read the codes and get unknown DTC 1C unknown DTC 1F and unknown DTC 2F.My local Volvo dealer tells me it is a temporary fault and i should "observe" which is not really helpful,Can somebody please advise as to what these codes actually mean

 

What year is your 850 ??

Are you getting those codes from an OBD II reader ??

Where are you located ??

 

What Codes You Can Get

Listed below is the information retrievable from the various connections.

• A1 Transmission
• B1 Climate Control
• A2 Fuel System
• B2 Cruise Control
• A3 ABS
• B5 SRS
• A5 TCU (Transmission Control)
• B6 Power Seat
• A6 Ignition System
• A7 Combined Instrument

I went in to see what "C" or "F" would be and can't find any reference to them. If it's an OBD II reader the codes should show up as "P x x x x" (four digits).

If you're using your under hood diagnostic connector it would be by connecting the jumper to A1 and getting a three digit code by counting the flashes.

A1 — Transmission

111 No faults found
112 Solenoid S1 short circuit to battery voltage
113 Transmission control module (TCM) fault
114 Program selector open circuit or short circuit to supply
121 Solenoid S1 short circuit to ground or control module fault
122 Solenoid S1 open circuit
123 Solenoid STH short circuit to battery voltage
124 Mode selector faulty or short circuit to ground
131 Solenoid STH open/short circuit or control module fault
132 Transmission control module(TCM) fault
134 Faulty load signal from ignition control module
141 Oil temperature sensor short circuit to ground
142 Oil temperature sensor open circuit
143 Kickdown switch faulty or short to ground
211 Transmission control module (TCM) fault
212 S2 solenoid short circuit to battery
213 Throttle position (TPS) signal too high
221 S2 solenoid short circuit to ground or control module fault
222 S2 solenoid open circuit
223 Throttle position (TPS) sensor signal too low
231 Throttle position (TPS) sensor sporadic
232 Speedometer signal missing
233 Incorrect speedometer signal
235 High Oil temperature
245 Open or short in Torque limiting circuit
311 RPM signal from transmission missing
312 RPM signal from transmission faulty
313 Faulty signal from gear position sensor (PNP)
321 Shift time too long
322 Incorrect gear ratio
323 Lock up slips or is not engaged
331 Short circuit to battery in SL circuit
332 SL solenoid open or control module fault
333 SL solenoid short or control module fault

If the flashing arrow is showing some times just "rowing" the shifter from Park through each position to 1st and back a few times might clear it up if it's a problem with the PNP or neutral safety switch on the transmission. The rowing helps to clean up the contacts some. There are also write ups on taking it apart and cleaning it.

 

1995 850 the codes are from OBD ll reader connected to lappy not handheld and i am unfortunately located in Germany hence not getting a proper answer from dealer

 

Any chance you have the under hood diagnostic panel ??
The one located over by the windshield washer fill ??

 

No i am afraid not just OBD ll by gear stick