P1550 fault code: what it means

P1550: Boost control is not reaching target. Power loss, juddering or limp mode.

Engine and gearbox (powertrain) · Costly if missed

Usual causes, most likely first

boost hose leak or wrong connection
faulty boost control valve (N75)
sticking turbo vanes or wastegate
faulty turbo

P1550 by make

Audi

Boost control is not reaching target. Power loss, juddering or limp mode.

Usual causes: boost hose leak or wrong connection; faulty boost control valve (N75); sticking turbo vanes or wastegate; faulty turbo

Lexus

Battery current sensor circuit range/performance on a Lexus: smart charging and stop-start may be disabled.

Usual causes: failed battery current sensor at the negative terminal; sensor wiring fault; aftermarket terminal fitted wrong

Nissan

Battery current sensor output stuck within range while running. Charging control and idle stop may be affected; battery may undercharge.

Usual causes: battery current sensor on the negative battery cable; wiring or connector fault; poor battery terminal connection

Skoda

Boost control is not reaching target. Power loss, juddering or limp mode.

Usual causes: boost hose leak or wrong connection; faulty boost control valve (N75); sticking turbo vanes or wastegate; faulty turbo

Toyota

Battery current sensor circuit fault (Toyota charging control). The ECM cannot see 12 V battery current, so stop-start and smart charging may be disabled.

Usual causes: failed battery current sensor on the negative terminal; sensor connector or wiring fault; aftermarket battery terminal fitted wrong

Volkswagen

Boost control is not reaching target. Power loss, juddering or limp mode.

Usual causes: boost hose leak or wrong connection; faulty boost control valve (N75); sticking turbo vanes or wastegate; faulty turbo

Volvo

Vehicle speed signal fault seen by the engine computer.

Usual causes: ABS wheel speed signal fault; data bus fault

What the repair usually costs

Automatic transmission rebuild, 6-speed and up (sent to specialist)NZ$7,190–NZ$13,080 · A$6,190–A$11,830
DSG / dual-clutch mechatronic unit replacement (new or reman)NZ$4,300–NZ$7,160 · A$3,750–A$6,390
DSG mechatronic repair / rebuild (unit sent to specialist)NZ$2,070–NZ$4,800 · A$1,890–A$4,250
A/C compressor replace incl. drier and flush (European)NZ$1,560–NZ$3,200 · A$1,490–A$3,050

Not sure what P1550 means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.