Error code

OBD2 P0299

OBD2P0299
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Turbo/Super Charger Underboost.

Severity

moderateThe vehicle can be driven but performance will likely suffer and there is a risk of further engine damage if the issue persists.

Summary

The P0299 code indicates that the turbocharger or supercharger is not providing sufficient boost pressure as detected by the powertrain control module (PCM). This issue can affect engine performance and efficiency.

Symptoms

  • Diminished engine performance
  • Irregular noises from the turbocharger wastegate and/or hoses, especially under acceleration
  • Heavy black smoke from the exhaust
  • Fouled spark plugs
  • Higher engine and/or transmission temperatures
  • Additional codes may also be stored, including other turbocharger boost related codes, engine misfire codes, or knock sensor codes

Common Causes

  • Mechanical failure of the turbocharger/supercharger
  • Faulty boost pressure sensor
  • Bad turbocharger bypass valve, wastegate, or blow-off valve
  • Disconnected, cracked, or collapsed vacuum lines (vacuum actuated bypass valve)
  • Disconnected or damaged turbocharger hoses
  • Loose, corroded, or disconnected electrical connectors in boost pressure sensor circuits
  • Defective PCM or boost controller

Diagnosis

  1. Inspect all wiring, turbocharger supply hoses, and vacuum hoses related to the turbocharger and boost control system.
  2. Retrieve stored trouble codes using a scanner and write them down.
  3. Clear the codes and test drive the vehicle if possible.
  4. Perform a manual boost pressure test and compare findings with manufacturer’s specifications.
  5. Test the boost pressure sensor and system circuits as needed.

Fixes

  • Repair or replace the faulty turbocharger/supercharger unit, boost pressure sensor, bypass control solenoid, PCM, or correct a PCM programming error.

FAQ

What should I do if my vehicle has P0299 code?

You should inspect the turbocharger/supercharger system for any mechanical issues and check electrical connections. If you're unsure, consult a professional mechanic.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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