VOLVO
TCM-0027 - Back-up (reverse) gear. Incorrect gear ratio
System
Transmission Control Module (TCM)
Volvo models this fault code applies to
Applies to the following models:
16 modelsC30 (2007–2013), C70 (2006–2013), C70 Cabriolet (1998–2005), C70 Coupé (1998–2002), S40 (1996–2004), S40 (2004–2013), S60 (2001–2009), S70 (1997–2000), S80 (1999–2006), V40 (1996–2004), V50 (2004–2013), V70 (1997–2000), V70 (2000–2008), V70 XC (1998–2000), V70 XC / XC70 (2001–2007), XC90 (2003–)
Show models by year and engine (39)
- Volvo C30 (2007–2013)2007–2013Transmission AW55-50/51SN only
- Volvo C70 (2006–2013)2006–2013Transmission AW55-50/51SN only
- Volvo C70 Cabriolet (1998–2005)1999Transmission AW50-42 only
- Volvo C70 Cabriolet (1998–2005)2000All transmissions except: M56
- Volvo C70 Cabriolet (1998–2005)2001–2005Transmission AW55-50/51SN only
- Volvo C70 Coupé (1998–2002)1999All engines except: B5254S DENSO · Transmission AW50-42 only
- Volvo C70 Coupé (1998–2002)2000All transmissions except: M56
- Volvo C70 Coupé (1998–2002)2001–2002Transmission AW55-50/51SN only
- Volvo S40 (1996–2004)2001–2004
- Volvo S40 (2004–2013)2004, 2011–2012Transmission AW55-50/51SN only
- Volvo S40 (2004–2013)2005–2010Transmission AW50/51 AWD, AW55-50/51SN only
- Volvo S60 (2001–2009)2001–2002
- Volvo S60 (2001–2009)2003, 2009All transmissions except: M58
- Volvo S60 (2001–2009)2004–2005Transmission AW50/51 AWD, AW55-50/51SN only
- Volvo S60 (2001–2009)2006–2008All transmissions except: M58, M66 AWD
- Volvo S70 (1997–2000)1999Transmission AW42 AWD, AW50-42 only
- Volvo S70 (1997–2000)2000All transmissions except: M56, M58
- Volvo S80 (1999–2006)1999–2004
- Volvo S80 (1999–2006)2005–2006All transmissions except: M56
- Volvo V40 (1996–2004)2001–2004
- Volvo V50 (2004–2013)2004, 2011–2012Transmission AW55-50/51SN only
- Volvo V50 (2004–2013)2005–2010Transmission AW50/51 AWD, AW55-50/51SN only
- Volvo V70 (1997–2000)1999All engines except: B5202FS, B5252FS, D5252T MSA 15.7, GB5252S, GB5252S2 · Transmission AW42 AWD, AW50-42 only
- Volvo V70 (1997–2000)2000All transmissions except: M56, M58
- Volvo V70 (2000–2008)2000–2002, 2008
- Volvo V70 (2000–2008)2003All transmissions except: M58
- Volvo V70 (2000–2008)2004–2005Transmission AW50/51 AWD, AW55-50/51SN only
- Volvo V70 (2000–2008)2006–2007All transmissions except: M58, M66 AWD
- Volvo V70 XC (1998–2000)1999Engine B5254T only · Transmission AW42 AWD only
- Volvo V70 XC (1998–2000)2000Transmission AW42 AWD only
- Volvo V70 XC / XC70 (2001–2007)2001–2002
- Volvo V70 XC / XC70 (2001–2007)2003–2005Transmission AW50/51 AWD only
- Volvo V70 XC / XC70 (2001–2007)2006–2007Transmission AW50/51 AWD, TF-80SC AWD only
- Volvo XC90 (2003–)2003, 2012, 2015
- Volvo XC90 (2003–)2004, 2006, 2011All transmissions except: M66 AWD
- Volvo XC90 (2003–)2005All transmissions except: M66 AWD, TF-80SC AWD
- Volvo XC90 (2003–)2007All transmissions except: M66 AWD, TF-80SC
- Volvo XC90 (2003–)2008–2010Transmission AW50/51 AWD, TF-80SC AWD only
- Volvo XC90 (2003–)2013–2014Transmission AW50/51 AWD only
What does this fault code mean?
The control module works out the transmission gear ratio from the input and output speed signals and compares it with the expected ratio for each gear. The fault code is set when the ratio in reverse deviates, and the gearbox can then be run in an emergency mode.
Possible causes
- Contact resistance in the circuit to the solenoids
- Interference with or faults in the signal from the transmission speed sensor
- Gear-shift position sensor incorrectly adjusted
- Transmission oil level too low
- Mechanical fault in the transmission, where worn components cause slipping or too low line pressure
What you can do
- 1Read the fault codes in all control modules before replacing anything, and deal with any other codes first
- 2Have a workshop check the transmission oil level and quality, and whether coolant has leaked into the oil
- 3Have a workshop check whether the transmission control module has the latest software, and update it if needed
- 4Clear the fault code and road test the car, including reversing, to see whether the fault returns
- 5If the fault remains, have a workshop check the connectors and wiring to the solenoids and the gear-shift position sensor, and repair or replace whatever is faulty
Symptoms you may notice5
- The general orange warning lamp is lit
- The malfunction indicator lamp (MIL) is lit
- No lock-up function
- Gear shifts slip abnormally
- Gear shifts are harsh
What the fault can affect2
- The control module's emergency program (Limp-home) is activated
- An emergency program, Emergency mode, is activated in the transmission control module
General guidance for car owners. Diagnosis on the car can point to a different cause.