GRX120 · GRX121 · GRX125
Toyota Mark X X120 import check
GRX120 is the factory model code for the Toyota Mark X X120, built for the Japanese market from 2004 to 2009. Other versions carry GRX121 and GRX125. Every genuine car has a chassis (frame) number that starts with its code, such as GRX120-. That number is the one thing that links its Japanese history to its UK records.
GRX120 at a glance
- Model code
- GRX120
- Make
- Toyota
- Model
- Mark X (X120)
- Body
- 4-door saloon
- Built
- 2004 to 2009
- Engine
- 4GR-FSE (2499 cc naturally aspirated petrol)
- Drivetrain
- RWD
- Japanese trims
- 250G, 250G Four, 300G, 300G Premium, S Package
- Chassis number format
- GRX120-nnnnnnn
From our own model library, compiled from public sources and not yet checked against a second source. UK records sometimes drop the hyphen or the leading zeros of the serial; our check allows for that.
Reading the GRX120 chassis code
- GRX120 is the 2.5 V6, GRX121 the 3.0 V6 and GRX125 the 2.5 with four-wheel drive.
- The second-generation Mark X (2009–2019) is GRX130.
| Code | What it is | Engine | Built |
|---|---|---|---|
| GRX120 | Mark X (X120) | 4GR-FSE | 2004–2009 |
| GRX121 | 3.0 V6 | 3GR-FSE | 2004–2009 |
| GRX125 | 2.5 V6, four-wheel drive | 4GR-FSE | 2004–2009 |
Have a chassis number? The chassis decoder reads it for you.
Is it a genuine GRX120?
The Mark X replaced the Mark II in 2004. A Mark X advertised as a 3.0 should be GRX121.
Known problems to check on a GRX120
- Carbon build-up and injector faults on the direct-injection GR engines
- Water pump leaks on the GR V6
- Worn front suspension bushes and ball joints
- Japanese-market radio and sat-nav need a band expander or replacement in the UK
These are common issues for the model, not facts about any particular car. Ask the seller about each one.
Before you buy
- Ask for the timing chain and water pump history on high-mileage cars
The GRX120 on a Japanese auction sheet
- The sheet names the car マークX (Mark X).
Most imports were bought at a Japanese auction, and the inspector’s sheet records the grade, mileage and every mark on the body. Ask the seller for it, then run it through our auction sheet translator to read it in English and check the chassis number and mileage against the UK record.
Recalls in Japan for the GRX120 family
Japan publishes every recall with the chassis numbers it covers. Run a recall check with the car’s chassis number to see whether any apply to it.
MOT record in the UK
Toyota Mark II, Chaser and Mark X
- 13% of 916 first MOT tests failed in 2024 and 2025, 60% lower than the UK average for cars of the same age.
- Most common advisory: Tread depth: worn close to legal limit or worn on edge (8.1% of tests).
- Most common failure: Washers: provides insufficient washer liquid (1.8% of tests).
From DVSA’s anonymised MOT data, licensed under the Open Government Licence v3.0.
Kilometres, miles and the first UK MOT
A GRX120 sold new in Japan has a speedometer in kilometres. When it is imported, the speedometer is either converted to miles or left in km, and the first UK MOT should record whichever the dial shows. Mistakes here are common, and they’re where mileage problems hide.
We put the Japanese auction mileage and every UK MOT reading on one timeline and check the crossing: whether the readings agree after converting, whether the km figure was written down as miles, and whether the first UK reading is lower than the car had already done in Japan. See an illustrative example.
Questions
What is the chassis code for the Toyota Mark X X120?
GRX120, with GRX121 and GRX125 for other engines or drive layouts. A Japanese-market Toyota Mark X X120 has a frame number that starts with its code, then a hyphen and a serial number. You’ll find it on the V5C and on a plate in the engine bay.
Which years was the GRX120 built?
From 2004 to 2009, with the 4GR-FSE (2499 cc naturally aspirated petrol) engine and RWD layout.
What should I check when buying a GRX120?
Carbon build-up and injector faults on the direct-injection GR engines. Water pump leaks on the GR V6. Worn front suspension bushes and ball joints. Japanese-market radio and sat-nav need a band expander or replacement in the UK. Ask for the timing chain and water pump history on high-mileage cars. Also check that the Japanese auction mileage lines up with the first UK MOT, because km and miles are easily mixed up.