P2A59Alternative Fuel Vaporizer B Outlet Temperature Sensor Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- On heavy vehicles the gas hardware sees constant shaking, and long harness runs to the vaporizers add connectors that can loosen. P2A59 records that the vaporizer B outlet signal changed faster or more erratically than real temperature can, or kept dropping out for short moments. Such faults tend to come and go with road surface, engine speed or coolant heat. The A sensor gives a good reference: if its value is smooth while B jumps, the problem is local to the B circuit. Look for green corrosion at the pins, cracked insulation and strain on the plug. No manufacturer documents P2A59; CARB still requires that sporadic faults on an input like this are detected. Expect occasional switching to petrol or a flickering gas indicator.
- What you may notice
- Check engine light comes and goes, depending on calibration
- Sporadic switching to petrol
- Flickering gas indicator
- Likely causes
- LikelyConnector of the B sensor loose or corroded
- PossibleHarness damaged by vibration or strain
- RareIntermittent contact inside the sensor
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.