Removing and installing gas rail temperature and pressure sensor GX21 — VW
Removing and installing gas rail temperature and pressure sensor GX21 on VW: factory workshop procedure for engines CPWA.
Workshop procedure for VW — the factory write-up, straight from real workshop data.
🔧 Engine codes this applies to
📋 Procedure
Removing and installing
gas rail temperature and pressure sensor
GX21
Gas rail temperature and pressure sensor
GX21
consists of
Gas rail sensor
G401
Temperature sender for alternative fuel system
G876
Special tools and workshop equipment required
Torque wrench
V.A.G 1331
Prerequisites for removal
DANGER
Risk of explosion and danger to life due to escaping natural gas. A hissing noise is a sign that there are leaks in the natural gas system. Leaks in natural gas system may lead to uncontrolled escape of natural gas.
Risk of explosion leading to serious injuries or death.
Do not perform any kind of work on the natural gas system if leaking gas can be heard.
If a gas leak can be heard (hissing), never drive the vehicle into the workshop.
Park the vehicle outside and cordon off the area.
Note
Before working on the natural gas system, always observe
Chapter
“
Safety precautions when working on natural gas system
”
!
Empty gas system
Rep. gr.
20
Fuel tank; Releasing pressure in high-pressure line
Pull off connector
1
and unscrew
gas rail temperature and pressure sensor
GX21
2
.
Installing
Install in reverse order.
Note
Natural gas system may not be operated until tested accordingly.
The necessary scope of the leakage test depends on the pressure section which has been worked on.
Observe the following allocation!
DANGER
Risk of explosion and danger to life due to escaping natural gas. Leaks in natural gas system may lead to uncontrolled escape of natural gas. Risk of explosion leading to serious injuries or death.
Check natural gas system for leaks.
Allocation:
Chapter
“
Different pressure sections of natural gas supply system
”
Open fuel tank shut-off valves
N361/N362
using
hand wheel
T50026
.
DANGER
Risk of explosion and danger to life due to escaping natural gas. A hissing noise is a sign that there are leaks in the natural gas system. Leaks in natural gas system may lead to uncontrolled escape of natural gas.
Risk of explosion leading to serious injuries or death.
Do not perform any kind of work on the natural gas system if leaking gas can be heard.
If a gas leak can be heard (hissing), never drive the vehicle into the workshop.
Park the vehicle outside and cordon off the area.
Check the gas system
Chapter
“
Checking gas system for leaks
”
.
Specified torques
Tightening gas rail sensor
Chapter
“
Assembly overview - gas rail
”
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
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The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.