P0168 Fuel Temperature Too High — Causes & Fix

What Does P0168 Mean?

P0168 means the fuel itself is running hotter than specification. On common-rail diesels the usual culprit is a large volume of hot return fuel from leaking injectors or a hard-working pump, often combined with low tank level. Sustained hot fuel thins, reduces lubrication and accelerates pump and injector wear, so the cause should be found promptly.

P0168 at a Glance

• What it means: Measured fuel temperature has exceeded its operating limit.
• Most common cause: Fuel temperature sensor failure
• Severity: Moderate to serious — rail-pressure faults cause power loss and non-starts.
• Can you drive?: Short distances in limp mode only. Diagnose promptly.
• Typical repair cost: £40-£150 for sensor/regulator work; £100-£350 per injector where back-leak is the cause.