Powertrain, generic (extended)

P2593 Turbocharger Speed Sensor B Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2593 concerns the second turbocharger speed sensor, found where an engine has two turbochargers, for example one per cylinder bank. It marks an electrical fault on that sensor's circuit that is not further classified; the specific forms are P2595 (low), P2596 (high) and P2597 (intermittent), while P2594 covers a plausibility error. Sensor A is reported separately under P2578-P2582. No manufacturer documents P2593 itself publicly. Bentley's W12 engine carries two such sensors (G688 for bank 1, G689 for bank 2), both engine control units store their faults, and the bulletin prescribes testing for opens, shorts to ground or B+ and wire-to-wire shorts before a sensor is changed. CARB requires these boost-control parts to be monitored.

Likely causes

Connector problem at speed sensor B
Harness to the second turbocharger damaged by heat or chafing
Internal failure of speed sensor B

Symptoms

  • Malfunction indicator lamp on
  • Power reduced, often only slightly with one turbo affected
  • No speed value for the second turbo in live data

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–800
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

turbo speed sensor bsensor wiring

Related codes

P2594P2595P2596P2597P2578

References: law.cornell.edu, static.nhtsa.gov.