Some diesels have a combustion pressure sensor in the glow plug; the engine module uses it to control injection for each cylinder. This code concerns cylinder 1. P0395 is the general circuit code for this pressure sensor, meant for modules that do not separate open circuits and shorts into low and high. The only manufacturer we found using this code family – GM's European 2.0 CDTI diesel, documented in Saab 9-5 workshop information – splits the faults into low and high (P0397, P0398) and does not use P0395; VW's US 2.0 TDI engines with pressure-sensing glow plugs report such faults with their own codes (P13CE ff). The description therefore follows CARB's requirement to monitor input sensors for circuit faults. The sensor has three wires (5 V reference, ground, signal); without it the module drops combustion control for that cylinder.
Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
Cylinder 1 is numbered according to the manufacturer: check your engine's manual before working on it.
Symptoms
- Check engine light on (often after two trips)
- Usually barely noticeable – combustion control for the cylinder is switched off
- Possibly rougher running, more noise or slightly higher consumption
Most likely causes
- Connector at the pressure-sensing glow plug loose or corroded
- Reference, signal or ground wire open or shorted
- Sensor electronics in the glow plug faulty
- Engine module (reference voltage or input)
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P0395 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 3: Ignition and misfires
- 95: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0395?
If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
What causes code P0395?
The most common causes are: connector at the pressure-sensing glow plug loose or corroded; reference, signal or ground wire open or shorted; sensor electronics in the glow plug faulty.
Related codes
- P0396Cylinder 1 Pressure Sensor Circuit Range/Performance
- P0397Cylinder 1 Pressure Sensor Circuit Low
- P0398Cylinder 1 Pressure Sensor Circuit High
- P0399Cylinder 1 Pressure Sensor Circuit Intermittent/Erratic
- P039FCylinder 2 Pressure Sensor Circuit
- P03A9Cylinder 3 Pressure Sensor Circuit
Sources
- law.cornell.edu: 13 CCR 1968.2
- borgwarner.com: pressure sensor glow plugs
- patents.google.com: US7726269
- saabwisonline.com: dtc p0397 p0398 p03a1 p03a2 p03ab p03ac p03b5 or p
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.