Error code

OBD2 P2021

OBD2P2021
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Intake Manifold Runner Position Sensor/Switch Circuit Low.

Severity

moderateCan drive but may experience performance issues and rough idle.

Summary

P2021 indicates an issue with the intake manifold runner position sensor/switch circuit on bank 2. This code is set when the PCM detects abnormally low voltage in this control circuit.

Symptoms

  • Stored trouble codes and illuminated warning light
  • Rough or fluctuating idle
  • Hesitation or surging at some engine speeds
  • Power loss at certain engine speeds and throttle settings

Common Causes

  • Damaged, burnt, shorted, disconnected, or corroded wiring and/or connectors
  • Defective position switch/sensor
  • Split, hardened, cracked, or dislodged vacuum lines (if applicable)
  • Carbon deposits on the control flaps preventing free movement

Diagnosis

  1. Record all fault codes and freeze frame data.
  2. Locate and identify the position sensor/switch, associated wiring, and vacuum lines (if applicable).
  3. Test resistance of the sensor using a digital multimeter and compare with manufacturer specifications.
  4. If necessary, test the operation of the sensor by monitoring signal voltage changes as control flaps are manually opened.

Fixes

  • Replace defective position switch/sensor if resistance or signal voltage readings deviate significantly from specified values.

FAQ

What should I do if the code returns after replacing the sensor?

Reconnect wiring and test for any issues with vacuum lines, carbon deposits on control flaps, or other related components.

Is it safe to drive with P2021?

It is drivable but may experience performance issues such as rough idle and hesitation. Address the issue promptly for optimal engine operation.

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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