P0299
Turbocharger or supercharger is producing less boost than the engine computer requested
Severity: Inspect soonTurbocharging, fuel pressure and EGR codes
Turbocharged and direct-injection engines rely on boost pressure and high fuel pressure, and many engines recirculate some exhaust (EGR) to lower combustion temperatures. The engine computer watches each one against a target and sets a code when it cannot reach it.
How these codes differ
- P0299 means the turbocharger or supercharger is making less boost than commanded (underboost). It points to a boost leak, a wastegate or actuator problem, or the turbo itself, and often comes with reduced power.
- P0087 means fuel rail or system pressure is below the target. On direct-injection engines that can be the high-pressure pump, the low-pressure supply feeding it, or the pressure sensor, and it often causes power loss or stalling.
- P0401 means EGR flow is lower than expected: the regulation requires the computer to detect low and high EGR flow. Low flow usually points to carbon-blocked passages or a sticking EGR valve rather than an electrical fault.
- The three can look alike from the driver's seat (power loss), but they point to different hardware: air side (P0299), fuel side (P0087) and exhaust recirculation (P0401).
Codes that show up together
- P0299 or P0087 with loss of power: both are known on turbocharged and direct-injection engines to cut performance, so check for open service bulletins on your vehicle before replacing parts, since several manufacturers have issued them for these codes.
Turbocharging, fuel pressure and EGR codes
P0087
Fuel pressure in the rail or supply system is lower than the engine computer requested
Severity: Inspect soonP0401
Exhaust gas recirculation (EGR) flow insufficient detected
Severity: MonitorP0089
Fuel pressure regulator not holding the pressure the computer asks for
Severity: Inspect soonP0191
Fuel rail pressure sensor reading does not make sense
Severity: Inspect soonP0088
Fuel rail pressure higher than the engine computer wants
Severity: Inspect soonP00C6
Fuel rail pressure too low while the engine is cranking
Severity: Inspect soonP0192
Fuel rail pressure sensor signal reads too low
Severity: Inspect soonP0234
Turbocharger or supercharger boost pressure is higher than the engine computer requested
Severity: Inspect soonP0404
The EGR valve or its position sensor is not working within the expected range
Severity: MonitorP228C
Fuel pressure regulator 1 cannot bring rail pressure up to target
Severity: Inspect soonP00AF
Turbo boost control module performance fault
Severity: Inspect soonP0240
Second boost sensor not reading as expected
Severity: Inspect soonP0402
EGR flow higher than the computer expects
Severity: MonitorP0405
EGR sensor circuit reading low
Severity: MonitorP0236
Turbo boost sensor reading does not make sense
Severity: Inspect soonP0403
EGR control circuit electrical fault
Severity: MonitorP0406
EGR position sensor signal too high
Severity: MonitorP0190
Fuel rail pressure sensor circuit fault
Severity: Severity not verifiedP1491
On Honda, the EGR valve does not lift enough; on Nissan, a fault in the EVAP vacuum cut valve bypass valve
Severity: Severity not verifiedP2562
Turbo boost control position sensor circuit fault
Severity: MonitorP2565
Turbo boost control position sensor signal reading too high
Severity: MonitorP0035
Turbo or supercharger bypass valve control circuit reads high
Severity: Inspect soonP003A
Turbo boost control position (vane or actuator) outside the range the computer has learned
Severity: Inspect soonP2263
Turbo or supercharger boost not matching the computer target (system A)
Severity: Inspect soonP0046
Turbocharger boost control circuit performance fault
Severity: Inspect soonP0235
A fault in the circuit of the turbocharger boost pressure sensor A
Severity: Severity not verifiedP0237
Turbo boost pressure sensor signal too low
Severity: Severity not verifiedP0238
The turbocharger boost pressure sensor A is reporting a signal that is too high
Severity: Inspect soonP0241
Turbo boost (manifold pressure) sensor B signal is too low
Severity: Severity not verifiedP0242
Turbo boost (manifold pressure) sensor B signal is too high
Severity: Severity not verifiedP0243
Turbocharger wastegate solenoid or regulating valve A: circuit malfunction
Severity: Severity not verifiedP0244
Turbocharger wastegate solenoid or regulating valve A: range/performance
Severity: Severity not verifiedP0245
Turbocharger wastegate solenoid or regulating valve A: circuit low
Severity: Severity not verifiedP0246
Wastegate solenoid A signal too high
Severity: Severity not verifiedP0247
Wastegate solenoid B not working correctly
Severity: Severity not verifiedP0248
Wastegate solenoid B outside expected performance
Severity: Severity not verifiedP0249
Wastegate solenoid B signal too low
Severity: Severity not verifiedP0250
Wastegate solenoid B signal too high
Severity: Severity not verifiedP0400
Exhaust gas recirculation flow is not what the computer expects
Severity: MonitorP0407
EGR valve position sensor B signal reads too low
Severity: Severity not verifiedP0408
EGR valve position sensor B signal reads too high
Severity: Severity not verifiedP0489
The computer sees a low voltage in the EGR valve control circuit
Severity: Severity not verifiedP226C
Turbocharger boost is slow to respond to what the computer commanded
Severity: Severity not verifiedP2563
Turbocharger boost control position sensor reading is out of range or does not make sense
Severity: Severity not verified
Sources and review
- Final Regulation Order: 13 CCR §1968.2, Malfunction and Diagnostic System Requirements (OBD II), 2004 and subsequent model-year passenger cars, light-duty trucks and medium-duty vehicles (2015 amendments)
- The basics of EGRs - what they do, how they work, how to troubleshoot
- RAM service bulletin 09-003-26 (P0299 turbocharger underboost)
- Volkswagen service bulletin 2036110 (Passat TDI, P0299 underboost)
- Audi service bulletin 2033211/1 (fuel rail pressure too low)
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error