Fault Family System: Powertrain (P-Codes) 5 SAE Codes

Turbo Interstage Pressure Sensor

Diagnostic & Technical Explanation

Code P2D21 (Turbocharger Interstage Pressure Sensor A Circuit) covers the pressure sensor mounted between stages on a sequential or two-stage turbocharger system, used to confirm the first-stage compressor is delivering the pressure the second stage needs. The ECM flags an open, shorted, out-of-range, or intermittent signal. Causes are a cracked or disconnected sense line between the stages, a failed sensor element, or a corroded connector.

These 5 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 5 times.

Codes in this family (5)

Code	Definition	Repair coverage
P2D21	Turbocharger Interstage Pressure Sensor A Circuit	3 ranked fixes
P2D22	Turbocharger Interstage Pressure Sensor A Circuit Range/Performance	3 ranked fixes
P2D23	Turbocharger Interstage Pressure Sensor A Circuit Low	3 ranked fixes
P2D24	Turbocharger Interstage Pressure Sensor A Circuit High	3 ranked fixes
P2D25	Turbocharger Interstage Pressure Sensor A Circuit Intermittent/Erratic	3 ranked fixes

What this page does not show

This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here:

Procedures 2..n after the first-listed procedure
Aftermarket parts cost ranges in USD (est_parts_cost_min/max_usd)
Professional labor-hour estimates (est_labor_hours)
Step-by-step diagnostic and repair instructions
Replacement-part mappings and catalog lookups
6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)

Need All 15,886 Codes as Data?

Pipe-delimited CSV, Apache Parquet and a relational SQLite database, with commercial application rights and instant download. Built for scan tools, shop software and research - not assembled one web page at a time.

License OEM Complete · $149 Standard (SAE only) · $49

$49 Standard: 9,249 SAE codes · $149 OEM Complete: all 15,886 codes, including 6,637 OEM codes across 32 makes · $149 Heavy Duty: 4,212 fault pairs (J1939) · one-time · compare tiers